Semiconductor light-emitting element and method of manufacturing the same, surface light-emitting semiconductor laser device and method of manufacturing the same, optical transmitting module, optical light transmitting/receiving module, and light communication system

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a semiconductor light emitting device, a method for manufacturing the same, a surface emitting semiconductor laser device, a method for manufacturing the same, an optical transmission module, an optical transmission / reception module, and an optical communication system.

【0002】

[Conventional technology]

In recent years, as seen in the explosive spread of the Internet, the amount of information handled has increased dramatically, and it is expected that it will accelerate further in the future. For this reason, optical fibers have been introduced not only to trunk lines, but also to subscriber systems such as homes and offices, transmission lines close to users such as LANs (Local Area Networks), and wiring between and within devices. Large-capacity information transmission technology is extremely important.

【0003】

In order to increase the capacity of optical networks and optical wiring at low cost without worrying about distance, as a light source, a surface emitting type of 1.3 μm band and 1.55 μm band with small transmission loss of silica fiber and good consistency. Semiconductor laser devices (VCSELs: Vertical Cavity Surface Emitting Lasers) are extremely promising.

【0004】

Surface-emitting semiconductor laser devices are suitable for lower cost, lower power consumption, miniaturization, and two-dimensional integration than end-face emission lasers, and are already faster in the 0.85 μm band that can actually be formed on a GaAs substrate. It has been put to practical use in 1 Gbit / s Ethernet (registered trademark), which is a LAN.

【0005】

On the other hand, in the 1.3 μm band, the material system on the InP substrate is common, and there is a track record in end face emission type lasers. However, this conventional long-wavelength semiconductor laser has a major drawback that the operating current increases three times when the environmental temperature rises from room temperature to 80 ° C. Further, in the surface emitting semiconductor laser element, it is difficult to improve the performance because there is no material suitable for the reflecting mirror, and the characteristics at a practical level have not been obtained at present.

【0006】

For this reason, the current highest performance is obtained by the structure in which the active layer on the InP substrate and the AlGaAs / GaAs reflector on the GaAs substrate are directly bonded together (reference "V. Jayaraman, JC Geske, MH MacDougal"). See FH Peters, TD Lowes, and TT Char, Electron. Lett., 34, (14), pp. 1405-1406, 1998.).

【0007】

However, since this method cannot avoid an increase in cost, it is considered that there is a problem in terms of mass productivity. Therefore, recently, a material system capable of forming a 1.3 μm band on a GaAs substrate has attracted attention, and (Ga) InAs quantum dots, GaAsSb and GaInNAs (see, for example, JP-A-6-37355) have been studied. GaInNAs, a new material, is attracting attention as a material that can extremely reduce the temperature dependence of laser characteristics.

【0008】

Since the band gap of a GaInNAs-based semiconductor laser on a GaAs substrate becomes smaller due to the addition of nitrogen, a long wavelength band such as a 1.3 μm band can be formed on the GaAs substrate. When the In composition is 10%, the nitrogen composition is about 3% and a 1.3 μm band can be formed, but there is a problem that the threshold current density rises sharply as the nitrogen composition increases.

【0009】

FIG. 1 is a diagram showing the nitrogen composition dependence of the threshold current density experimentally obtained by the inventor of the present application, the horizontal axis showing the nitrogen composition ratio (%), and the vertical axis showing the threshold current density. Is shown. From FIG. 1, it can be seen that the larger the nitrogen composition, the sharper the threshold current density. As described above, the reason why the threshold current density increases sharply as the nitrogen composition increases is that the crystallinity of the GaInNAs layer deteriorates as the nitrogen composition increases.

【0010】

Therefore, the issue is how to grow GaInNAs with high quality. MOCVD (Metal Organic Chemical Vapor Deposition) and MBE (Molecular Beam Epitaxy) have been tried as such crystal growth methods for GaInNAs.

【0011】

The MOCVD method does not require a high vacuum like the MBE method, and while the MBE method controls the raw material supply by changing the cell temperature, the MOCVD method only needs to control the raw material gas flow rate. Moreover, since the growth rate can be increased and the throughput can be easily increased, it is an extremely suitable growth method for mass production. The MOCVD method is used in all (in most cases) production of 0.85 μm band surface emitting semiconductor laser devices that are actually put into practical use.

【0012】

Recently, many reports of semiconductor lasers using this novel GaInNAs-based material have been reported. However, most of these were by the MBE method. Further, Japanese Patent Application Laid-Open No. 9-237942 proposes a surface emitting laser using a GaInNAs-based material. Most recently, the operation of surface-emitting semiconductor laser devices using GaInNAs-based materials has also been reported.

【0013】

[Problems to be Solved by the Invention]

However, most of the reports of this novel GaInNAs-based surface emitting semiconductor laser device have been grown by the MBE method and do not have sufficient characteristics. Conventionally, a method and an apparatus for manufacturing a GaInNAs-based surface emitting semiconductor laser device by the MOCVD method suitable for mass production have not yet been established.

【0014】

The present invention provides a high-quality, practical-level GaInNAs-based semiconductor light emitting device and a method for manufacturing the same, a surface emitting semiconductor laser device and the manufacturing method thereof, an optical transmission module, an optical transmission / reception module, and an optical communication system that can be manufactured by the MOCVD method. The purpose is to do.

【0015】

[Means for solving problems]

In order to achieve the above object, the invention according to claim 1 grows a semiconductor layer containing Al in a method for manufacturing a semiconductor light emitting device in which a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen. Later, before starting the growth of the active layer containing nitrogen, a chlorine-based compound gas is supplied to the growth chamber as an etching gas, and the Al raw material, the Al reaction product, or the Al compound remaining in the growth chamber is supplied. Or, it is characterized by providing a step of removing Al.

【0016】

The invention according to claim 2 is a step of removing an Al raw material, an Al reaction product, an Al compound, or Al remaining in the growth chamber in the method for manufacturing a semiconductor light emitting device according to claim 1. Is characterized in that the growth of the semiconductor light emitting device is interrupted, the substrate to be grown of the semiconductor light emitting device is moved from the growth chamber to another chamber, or once taken out to the outside.

【0017】

Further, the invention according to claim 3 uses the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber as the etching gas in the method for producing the semiconductor light emitting device according to claim 1. It is characterized in that a GaInP layer, a GaPAs layer, or a GaInPAs layer is formed after the step of removing the chlorine-based compound gas from the above, and before the active layer containing nitrogen is grown.

【0018】

The invention according to claim 4 is a semiconductor light emitting device manufactured by the method for manufacturing a semiconductor light emitting device according to any one of claims 1 to 3.

【0019】

The invention according to claim 5 is provided on a semiconductor substrate in an active region including at least one nitrogen-containing active layer that generates laser light, and above and below the active layer in order to obtain laser light. In a method for manufacturing a surface-emitting semiconductor laser element having a top reflector and a lower reflector, and a resonator structure sandwiched between the upper reflector and the lower reflector, the lower reflector has a periodic refractive index. Al_xGa_1-xThe layer consisting of As (0 <x 1) and having a large refractive index of the semiconductor distributed Bragg reflector is Al._yGa_1-yAs (0 y <x 1), after growing the lower reflector containing Al, before growing the active layer containing nitrogen, a chlorine-based compound gas was introduced into the growth chamber as an etching gas. It is characterized in that it is supplied and the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber is removed.

【0020】

Further, the invention according to claim 6 uses the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber in the method for producing a surface emitting semiconductor laser device according to claim 5. A GaInP layer, a GaPAs layer, or a GaInPAs layer is provided after the step of removing with a chlorine-based compound gas as an etching gas and before the active layer containing nitrogen is grown, and the etching is performed. The step of removing with gas is characterized in that it is performed while the semiconductor distributed Bragg reflector is growing.

【0021】

Further, the invention according to claim 7 uses the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber in the method for producing the surface emitting semiconductor laser device according to claim 5. A GaInP layer, a GaPAs layer, or a GaInPAs layer is provided after the step of removing with a chlorine-based compound gas as an etching gas and before the active layer containing nitrogen is grown, and the etching is performed. The step of removing with gas is characterized in that it is performed while the resonator structure is growing.

【0022】

The invention according to claim 8 is a surface emitting semiconductor laser device, characterized in that it is manufactured by the method for manufacturing a surface emitting semiconductor laser device according to any one of claims 5 to 7. is there.

【0023】

The invention according to claim 9 is an optical transmission module characterized in that the surface emitting semiconductor laser element according to claim 8 is used as a light source.

【0024】

The invention according to claim 10 is an optical transmission / reception module characterized in that the surface emitting semiconductor laser element according to claim 8 is used as a light source.

【0025】

The invention according to claim 11 is an optical communication system characterized in that the surface emitting semiconductor laser element according to claim 8 is used as a light source.

【0026】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

【0027】

First, the cause that hinders the high performance of the GaInNAs-based surface emitting semiconductor laser device by the MOCVD method will be described based on the experimental results of the inventor of the present application.

【0028】

FIG. 2 is a diagram showing an outline of a general MOCVD apparatus. The MOCVD method is a vapor phase growth method in which at least a part of an organometallic raw material is used and crystals are grown by thermal decomposition of the raw material gas and a surface reaction with a substrate to be grown. As shown in FIG. 2, the MOCVD apparatus has already reacted with the raw material gas supply unit to which the raw material gas is supplied, the heating means (not shown) for heating the substrate to be grown, and the heating unit (heater). It has an exhaust unit (exhaust pump, etc.) for exhausting the gas. Normally, the substrate is introduced from the substrate inlet / outlet so that air does not enter the growth chamber (reaction chamber), and is conveyed to the growth chamber (reaction chamber) after being evacuated by the exhaust unit. The pressure in the reaction chamber (growth chamber) is often reduced to about 50 Torr to 100 Torr. The raw material gas supply unit is usually divided into a group III gas line and a group V gas line. In Fig. 2, the group III gas line and the group V gas line merge in front of the entrance of the reaction chamber.

【0029】

Here, as the group III raw material, organic metals such as Ga: TMG (trimethylgallium), TEG (triethylgallium), Al: TMA (trimethylaluminum), and In: TMI (trimethylindium) are used. In addition, AsH is used as a V-group raw material.₃(Arsine), TBA (Tarshall Butyl Arsine), PH₃Hydride gas and organic compounds such as (phosphine) and TBP (talshal butylarsine) are generally used.

【0030】

The carrier gas is hydrogen gas (H).₂) Is commonly used and hydrogen gas (H)₂) Is usually supplied after removing impurities through a hydrogen purifier. Then, an organic compound such as DMHy (dimethylhydrazine) or MMHy (monomethylhydrazine) can be used as a raw material of nitrogen for the growth of the semiconductor layer containing nitrogen. The raw material is not limited to this. Liquid or solid raw materials such as organometallics and organic nitrogen compounds are supplied by being placed in a bubbler and bubbled through a carrier gas. In addition, the hydride is supplied in a gas cylinder. In Fig. 2, AsH is used for TMG, TMA, TMI, and DMHy using a bubbler (liquid, solid raw material bubbler).₃And a gas cylinder is used for the dopant gas (only one type is shown in Fig. 2).

【0031】

The required material and composition can be grown by switching the route of the raw material gas with a valve and controlling the supply amount of the raw material gas with an MFC mass flow controller or the like. Generally, each group III gas line and group V gas line has a main line for supplying gas to the reaction chamber and a vent line for supplying gas to the exhaust pump, and a dummy line in addition to the raw material line (Fig. (Refer to middle and dummy lines 1 and 2), switch the valve so that it joins either the main line or the vent line, and eliminate the pressure difference between the main line and the vent line so that the gas flow is not disturbed as much as possible. I have to. Carrier gas is also supplied to the main line, vent line, and dummy line. In such a MOCVD apparatus, when growing a semiconductor light emitting device or the like having a plurality of semiconductor layers, the necessary raw materials for each layer are supplied to the main line side, and the carrier gas from the dummy line is supplied to the vent side. , Crystal growth is carried out. The thickness of growth is controlled by the time during which the source gas is supplied. As a result, the required structure can be grown, so the throughput is good and it is suitable for mass production.

【0032】

FIG. 3 shows the room temperature photoluminescence spectrum from the active layer consisting of the GaInNAs quantum well layer and the GaAs barrier layer, which are nitrogen-containing semiconductor layers produced by such a MOCVD apparatus, and the active layer consisting of the GaInNAs / GaAs 2-heavy well structure. It is a figure which shows. In FIG. 3, reference numeral A is a sample in which a GaAs intermediate layer is sandwiched on an AlGaAs clad layer to form a double weight well structure, and reference numeral B is a sample in which a GaAs intermediate layer is sandwiched on a GaInP clad layer. It is a sample in which the structure is continuously formed. Note that FIG. 4 shows the basic structures of samples A and B. That is, referring to FIG. 4, in the samples A and B, basically, the lower clad layer 202, the intermediate layer 203, the active layer 204 containing nitrogen, the intermediate layer 203, and the upper clad layer 205 are formed on the GaAs substrate 201. It is configured by being sequentially laminated.

【0033】

As shown in FIG. 3, the photoluminescence intensity of sample A is reduced to less than half that of sample B. Therefore, if an active layer containing nitrogen such as GaInNAs is continuously formed on a semiconductor layer containing Al such as AlGaAs as a constituent element using one MOCVD apparatus, the emission intensity of the active layer deteriorates. There was a problem. Therefore, the threshold current density of the GaInNAs-based laser formed on the AlGaAs clad layer is several times higher than that when it is formed on the GaInP clad layer.

【0034】

The inventor of the present application examined the elucidation of the cause. FIG. 5 shows, as an example of the semiconductor light emitting device shown in FIG. 4, epitaxial growth of one device in which the clad layer 202 is AlGaAs, the intermediate layer 203 is GaAs, and the active layer 204 is a GaInNAs / GaAs2 weight well structure. It is a figure which shows the distribution in the depth direction of a nitrogen (N) concentration and an oxygen (O) concentration when formed by using an apparatus (MOCVD). This measurement was performed by SIMS. The following table (Table 1) shows the measurement conditions.

【0035】

[table 1]

<img file="JP2003198060A_D0001.tif" />【0036】

In FIG. 5, two nitrogen peaks are found in the active layer 204, corresponding to the GaInNAs / GaAs2 weight well structure. Then, a peak of oxygen is detected in the active layer 204. However, the oxygen concentration in the intermediate layer 203 containing no N and Al is about an order of magnitude lower than the oxygen concentration in the active layer 204.

【0037】

On the other hand, when the depth distribution of oxygen concentration is measured for a semiconductor laser device in which the clad layer 202 is GaInP, the intermediate layer 203 is GaAs, and the active layer 204 is a GaInNAs / GaAs2 weight well structure, the activity is active. The oxygen concentration in layer 204 was at background levels .

【0038】

That is, a semiconductor in which a semiconductor layer (202) containing Al is provided between a substrate (201) and an active layer (204) containing nitrogen by one epitaxial growth device using a nitrogen compound raw material and an organic metal Al raw material. It has been clarified by the experiment of the inventor of the present application that oxygen is taken into the active layer (204) containing nitrogen when the light emitting device is continuously crystal-grown. Oxygen taken into the active layer (204) forms a non-luminescent recombination level, which reduces the luminous efficiency of the active layer (204). Oxygen taken into the active layer (204) reduces the luminous efficiency in a semiconductor light emitting device in which a semiconductor layer (202) containing Al is provided between the substrate (201) and the active layer containing nitrogen (204). It was newly found that it was the cause of the problem. The origin of this oxygen is considered to be a substance containing oxygen remaining in the apparatus or a substance containing oxygen contained as an impurity in the nitrogen compound raw material.

【0039】

Next, the cause of oxygen uptake was examined. FIG. 6 is a diagram showing the distribution of Al concentration in the depth direction in the same sample as in FIG. The measurement was performed by SIMS. The following table (Table 2) shows the measurement conditions.

【0040】

[Table 2]

<img file="JP2003198060A_D0002.tif" />【0041】

From FIG. 6, Al is detected in the active layer 204 into which the Al raw material is not originally introduced. However, in the intermediate layer (GaAs layer) 203 adjacent to the semiconductor layers (clad layers) 202 and 205 containing Al, the Al concentration is about an order of magnitude lower than that of the active layer 204. This indicates that Al in the active layer 204 is not mixed by diffusing or substituting from the semiconductor layers (clad layers) 202 and 205 containing Al.

【0042】

On the other hand, when an active layer containing nitrogen was grown on a semiconductor layer containing no Al like GaInP, Al was not detected in the active layer.

【0043】

Therefore, in FIG. 6, the Al detected in the active layer 204 is the Al raw material or Al reaction product remaining in the apparatus, or the Al compound, or Al is in the nitrogen compound raw material or the nitrogen compound raw material. It is incorporated into the active layer 204 by combining with impurities (moisture, etc.). That is, when a semiconductor light emitting device in which a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen is continuously crystal-grown by one epitaxial growth device using a nitrogen compound raw material and an organic metal Al raw material. , The inventor of the present application has newly found that Al is naturally taken up in the active layer containing nitrogen.

【0044】

Comparing with the depth distribution of nitrogen concentration and oxygen concentration in the same semiconductor light emitting device shown in FIG. 5, the two oxygen peak profiles in the 2-weight child well active layer 204 correspond to the peak profile of nitrogen concentration. It corresponds to the Al concentration profile in Fig. 6. From this, it was clarified that the oxygen impurities in the GaInNAs well layer are not taken up together with the nitrogen raw material, but rather are taken up together with Al taken up in the well layer. .. That is, when the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber comes into contact with the nitrogen compound raw material, the water contained in the Al and the nitrogen compound raw material or the gas line or the reaction chamber. Al and oxygen are taken into the active layer 204 by combining with a substance containing oxygen such as residual water. It was clarified for the first time by the experiment of the inventor of the present application that the oxygen taken into the active layer 204 reduced the luminous efficiency of the active layer 204.

【0045】

When manufactured by the usual MBE method, a decrease in luminous efficiency in a semiconductor light emitting device in which a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen has not been reported.

【0046】

This is because the MBE method grows crystals under ultra-low pressure (in high vacuum), while the MOCVD method usually has a pressure of several tens of Torr to atmospheric pressure, which is higher than that of the MBE method in the reaction chamber. It is considered that the free path is overwhelmingly short, and the supplied raw materials, carrier gas, etc. come into contact with and react with the Al-based residue in the reaction chamber or the like.

【0047】

Therefore, in the case of a growth method in which the pressure in the reaction chamber or gas line is high, such as the MOCVD method, in order to improve this, at least Al remaining in the apparatus enters the membrane together with oxygen when the active layer containing nitrogen grows. It was found that a step of removing Al-based residues was necessary so that they would not be taken up.

【0048】

Therefore, the embodiment of the present invention is characterized in that the following configuration is adopted. Hereinafter, each embodiment will be described in detail.

【0049】

First Embodiment First, the method for manufacturing a semiconductor light emitting device according to the first embodiment of the present invention is a method for manufacturing a semiconductor light emitting device in which a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen. However, before starting the growth of the active layer containing nitrogen, a chlorine-based compound gas is supplied into the growth chamber (reaction chamber) as an etching gas, and the Al raw material remaining in the growth chamber or the Al raw material or It is characterized by providing a step of removing an Al reaction product, an Al compound, or Al.

【0050】

As described above, the Al-based residue causes oxygen, which causes non-luminescent recombination, to be taken into the active layer containing nitrogen. Therefore, after growing the semiconductor layer containing Al, nitrogen is added. Before the growth of the active layer containing it, the Al-based residue is removed by reacting with the Al-based residue remaining on the side wall of the reaction chamber (growth chamber), the heating zone, the jig holding the substrate, etc. By supplying the produced gas to the growth chamber, the uptake of oxygen into the active layer can be suppressed. Chlorine-based compound gas such as HCl has the effect of reacting with the reaction-generated deposits in the growth chamber and removing by etching. Therefore, if a chlorine-based compound gas is supplied as an etching gas after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown, this etching gas holds the side wall of the reaction chamber, the heating zone, and the substrate. Since the Al-based residue can be removed by reacting with the Al-based residue remaining on the jig or the like, the uptake of oxygen into the active layer can be suppressed. A chlorine-based compound gas (for example, HCl gas) can be used by filling a gas cylinder. In this case, a high-purity product with less oxygen, water, etc. is preferable.

【0051】

By this method, the Al concentration in the active layer containing nitrogen is 1 × 10.¹⁹cm^-3It can be reduced to the following, which enables continuous oscillation at room temperature. Furthermore, the Al concentration in the active layer containing nitrogen is 2 × 10.¹⁸cm^-3By reducing the amount to the following, light emission characteristics equivalent to those when formed on a semiconductor layer containing no Al were obtained.

【0052】

Table 3 shows the results of trial production of a broad stripe laser using AlGaAs as a clad layer (layer containing Al) and GaInNAs2 weight well structure (layer containing nitrogen) as an active layer and evaluating the threshold current density. ..

【0053】

[Table 3]

<img file="JP2003198060A_D0003.tif" />【0054】

From Table 3, in the structure in which the active layer containing nitrogen is continuously formed in the semiconductor layer containing Al as a constituent element, 2 × 10 in the active layer.¹⁹cm^-3The above Al and 1 × 10¹⁸cm^-3The above oxygen is taken in, and the threshold current density is 10 kA / cm.²It was a remarkably high value as above. However, the Al concentration in the active layer is 1 × 10.¹⁹cm^-3By reducing to the following, the oxygen concentration in the active layer is 1 × 10¹⁸cm^-3Reduced below, threshold current density 2-3 kA / cm²The broad stripe laser oscillated at. Broad stripe laser threshold current density is several kA / cm²With the following active layer quality, room temperature continuous oscillation is possible. Therefore, the Al concentration in the active layer containing nitrogen is 1 × 10.¹⁹cm^-3By suppressing the following, it is possible to manufacture a semiconductor laser capable of continuously oscillating at room temperature.

【0055】

As described above, in the first embodiment, in the method for manufacturing a semiconductor light emitting device in which a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen, after the semiconductor layer containing Al is grown, Before starting the growth of the active layer containing nitrogen, a chlorine-based compound gas is supplied to the growth chamber as an etching gas, and the Al raw material or Al reaction product, the Al compound, or Al remaining in the growth chamber is charged. Since it is removed, the uptake of oxygen into the active layer can be suppressed, and a semiconductor light emitting device having high light emission efficiency can be obtained.

【0056】

Second embodiment The method for producing a semiconductor light emitting device according to the second embodiment of the present invention is the Al raw material, Al reaction product, or Al compound remaining in the growth chamber in the method for producing the semiconductor light emitting device according to the first embodiment. Or, when performing the step of removing Al, the growth of the semiconductor light emitting device is interrupted, and the substrate to be grown of the semiconductor light emitting device is moved from the growth chamber to another chamber, or is once taken out to the outside. ..

【0057】

The chlorine-based compound gas has the effect of reacting with the reaction-generated deposits in the growth chamber to remove the etching, and also has the effect of etching the substrate to be grown. Alternatively, when performing the step of removing the Al compound or Al, it is preferable not to place the substrate to be grown of the semiconductor light emitting element in the growth chamber. Of course, it is also possible to assume that the substrate to be grown is etched in advance and to grow it thicker by that amount so that the substrate to be grown can be continuously performed without moving.

【0058】

Third embodiment The method for manufacturing a semiconductor light emitting device according to the third embodiment of the present invention is the Al raw material, the Al reaction product, the Al compound, or the Al compound remaining in the growth chamber in the method for manufacturing the first semiconductor light emitting device. After performing the step of removing Al with a chlorine-based compound gas as an etching gas, and before growing the active layer containing nitrogen, it is necessary to form a GaInP layer, a GaPAs layer, or a GaInPAs layer. It is a feature.

【0059】

As described above, in the step of removing the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber with the chlorine-based compound gas, for example, the growth of the semiconductor light emitting device is interrupted. , The substrate to be grown of the semiconductor light emitting device can be moved from the growth chamber to another chamber, or can be taken out once and then carried out. However, when the substrate to be grown is moved to another chamber, an oxide film is formed on the surface of the epi substrate by moving the substrate to be grown to another chamber. If this interface is an active region in which carriers are injected, it becomes a non-emission recombination center and the luminous efficiency decreases when the light emitting device operates.

【0060】

On the other hand, when a material having a bandgap energy higher than the bandgap energy of the surface material at the time of growth interruption is grown between the active layer containing nitrogen, the injection carriers to the growth interruption interface are almost eliminated, so that the luminous efficiency is reduced. Can be prevented from decreasing. SIMS analysis of this growth-interrupted interface will reveal oxygen (O) or nitrogen (N) or chlorine (Cl). As the material having a bandgap energy higher than the bandgap energy of the surface material at the time of growth interruption, any material containing no Al may be used for the purpose of the invention, and a GaInP layer, a GaPAs layer, or a GaInPAs layer is used. be able to. Of course, it may contain other elements such as N and Sb. Further, these materials may be lattice-matched and may have distortion as long as the thickness is equal to or less than the critical film thickness. For example, when the active layer has compressive strain, if these materials are made into tensile strain, there is an effect of compensating for the strain of the active layer.

【0061】

Fourth Embodiment The semiconductor light emitting device according to the fourth embodiment of the present invention is characterized in that it is manufactured by the manufacturing method according to any one of the first to third embodiments.

【0062】

Since the semiconductor light emitting device according to the fourth embodiment of the present invention is manufactured by the production method according to any one of the first to third embodiments, the uptake of oxygen into the active layer can be suppressed and the luminous efficiency can be improved. It is possible to provide an expensive semiconductor light emitting device.

【0063】

Fifth embodiment The method for manufacturing a surface-emitting semiconductor laser element according to a fifth embodiment of the present invention obtains an active region including at least one nitrogen-containing active layer that generates laser light and laser light on a semiconductor substrate. Therefore, in a method for manufacturing a surface emitting semiconductor laser element having an upper reflector and a lower reflector provided at the upper and lower portions of the active layer and a resonator structure sandwiched between the upper reflector and the lower reflector. The lower reflector has a semiconductor distributed Bragg reflector whose refractive index changes periodically and reflects incident light by light wave interference, and the layer having a small refractive index of the semiconductor distributed Bragg reflector is Al._xGa_1-xThe layer consisting of As (0 &lt;x 1) and having a large refractive index of the semiconductor distributed Bragg reflector is Al._yGa₁_-yAs (0 y &lt;x 1), after growing the lower reflector containing Al, before growing the active layer containing nitrogen, a chlorine-based compound gas was introduced into the growth chamber as an etching gas. It is characterized in that it is supplied and the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber is removed.

【0064】

Examples of the nitrogen-containing semiconductor layer include GaNAs, GaInNAs, InNAs, GaAsNSb, and GaInNAsSb. For example, GaInNAs will be described below. By adding N to GaInAs, which has a larger lattice constant than GaAs, GaInNAs can be lattice-matched to GaAs, and its bandgap becomes smaller, enabling light emission in the 1.3 μm and 1.55 μm bands. Moreover, since it is a GaAs substrate lattice matching system, wide-gap AlGaAs and GaInP can be used for the clad layer.

【0065】

Furthermore, the addition of N reduces the bandgap as described above, lowers the energy levels of both the conduction band and the valence band, and the band discontinuity of the conduction band in the heterojunction becomes extremely large, resulting in the operating current of the laser. The temperature dependence can be made extremely small.

【0066】

Further, the surface-emitting semiconductor laser device is advantageous for parallel transmission due to miniaturization, low power consumption, and two-dimensional integration. It is difficult for surface-emitting semiconductor laser devices to obtain performance that can withstand practical use with conventional GaInPAs / InP systems, but according to GaInNAs-based materials, 0.85 μm band-emitting semiconductor laser devices using GaAs substrates can be used. Since the proven Al (Ga) As / (Al) GaAs semiconductor multilayer film distribution Bragg reflector and the current narrowing structure by selective oxidation of AlAs can be applied, practical application can be expected.

【0067】

In order to achieve this, it is important to improve the crystal quality of the GaInNAs active layer, reduce the resistance of the multilayer film reflector, and improve the crystal quality and controllability of the multilayer film structure as a surface-emitting semiconductor laser device. However, in this fifth embodiment, after the lower reflector containing Al is grown and before the active layer containing nitrogen is grown, the chlorine-based compound gas is supplied to the growth chamber to grow. Since the Al raw material, Al reaction product, Al compound, or Al remaining in the room is removed, it is possible to suppress the uptake of oxygen, which is the center of non-luminescence recombination, into the active layer containing nitrogen. It is possible to easily realize a surface-emitting semiconductor laser device having low resistance, low drive voltage, high light emission efficiency, low threshold current operation, and good temperature characteristics at low cost. In the step of removing the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber, the substrate to be grown is moved from the growth chamber to another chamber, or once taken out to the outside. It is preferable to start from.

【0068】

Sixth embodiment The method for manufacturing a surface-emitting semiconductor laser device according to the sixth embodiment of the present invention is the Al raw material or Al reaction product remaining in the growth chamber in the method for manufacturing the surface-emitting semiconductor laser device according to the fifth embodiment. , Or, after performing the step of removing the Al compound or Al with a chlorine-based compound gas as an etching gas, and before growing the active layer containing nitrogen, the GaInP layer, the GaPAs layer, or , The step of providing the GaInPAs layer and removing it with the etching gas is characterized in that it is performed while the semiconductor distributed Bragg reflector is growing.

【0069】

If the etching removal step is provided in the active region in which the carrier is injected, non-emission recombination may occur due to oxidation or the like and the luminescence efficiency may decrease, but it remains in the growth chamber as in the sixth embodiment. After performing the step of removing the Al raw material, the Al reaction product, the Al compound, or Al with a chlorine-based compound gas as an etching gas, and before growing the active layer, the low refractive index layer of the reflector When a GaInP layer, a GaPAs layer, or a GaInPAs layer is grown as a part of, a narrow gap material (for example, GaAs) is formed in a region closer to the active layer than the GaInP layer, the GaPAs layer, or the GaInPAs layer. Since it is possible to form an active region by using it, there is no concern about the above-mentioned decrease in light emission efficiency, and it is possible to eliminate the influence on the device performance by the non-emission recombination center in the region where the Al-based residue removal step is performed. It is possible to obtain a surface-emitting semiconductor laser device that operates with a low threshold current and has good temperature characteristics.

【0070】

Seventh embodiment The method for manufacturing a surface-emitting semiconductor laser device according to the seventh embodiment of the present invention is the Al raw material or Al reaction product remaining in the growth chamber in the method for manufacturing the surface-emitting semiconductor laser device according to the fifth embodiment. , Or, after performing the step of removing the Al compound or Al with a chlorine-based compound gas as an etching gas, and before growing the active layer containing nitrogen, the GaInP layer, the GaPAs layer, or , The step of providing the GaInPAs layer and removing it with the etching gas is characterized in that it is performed while the resonator structure is growing. Here, the resonator structure is a region sandwiched between the lower reflector and the upper reflector.

【0071】

The step of removing the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber with a chlorine-based compound gas is after growing the lower reflector containing Al, and the nitrogen is removed. It may be carried out before the active layer containing the mixture is grown, and may be carried out in a resonator. However, if the removal step is provided in the active region where the carrier is injected, non-emission recombination may occur due to oxidation or the like and the luminescence efficiency may decrease, but the growth is interrupted at the resonator portion and remains in the growth chamber. After performing the step of removing the Al raw material, the Al reactant, the Al compound, or Al with an etching gas (for example, a chlorine-based compound gas), and before growing the active layer, the GaInP layer or GaPAs When the layer or GaInPAs layer is grown, it is possible to form an active region using a narrow gap material (for example, GaAs) in a region closer to the active layer than the GaInP layer, the GaPAs layer, or the GaInPAs layer. Therefore, even if the growth is interrupted in the resonator, there is no concern that the light emission efficiency will decrease, and the influence on the device performance due to the non-light emission recombination center in the region where the Al-based residue removal step has been performed can be eliminated. It is possible to obtain a surface-emitting semiconductor laser device that operates with a low threshold current and has good temperature characteristics.

【0072】

Eighth embodiment The surface-emitting semiconductor laser device according to the eighth embodiment of the present invention is characterized in that it is manufactured by the manufacturing method according to any one of the fifth to seventh embodiments.

【0073】

Since the surface-emitting semiconductor laser device of the eighth embodiment of the present invention was produced by the production method of any one of the fifth to seventh embodiments, the oxygen as the non-emission recombination center contains nitrogen-containing activity. A surface-emitting semiconductor laser device with low resistance, low drive voltage, high emission efficiency, low threshold current operation, and good temperature characteristics can be easily realized at low cost. it can.

【0074】

Ninth embodiment The optical transmission module of the ninth embodiment of the present invention is characterized in that the surface emitting semiconductor laser element of the eighth embodiment is used as a light source.

【0075】

A low-cost optical transmission module that does not require a cooling element by using a surface-emitting semiconductor laser device with low resistance, low drive voltage, low threshold current operation, and good temperature characteristics as in the eighth embodiment. Can be realized.

【0076】

Tenth embodiment The optical transmission / reception module of the tenth embodiment of the present invention is characterized in that the surface emitting semiconductor laser element of the eighth embodiment is used as a light source.

【0077】

A low-cost optical transmission / reception module that does not require a cooling element by using a surface-emitting semiconductor laser element that has low resistance, low drive voltage, low threshold current operation, and good temperature characteristics as in the eighth embodiment. Can be realized.

【0078】

Eleventh embodiment The optical communication system of the eleventh embodiment of the present invention is characterized in that the surface emitting semiconductor laser element of the eighth embodiment is used as a light source.

【0079】

A low-cost optical fiber communication system that does not require a cooling element by using a surface-emitting semiconductor laser device that has low resistance, low drive voltage, low threshold current operation, and good temperature characteristics as in the eighth embodiment. It is possible to realize an optical communication system such as an optical interconnection system.

【0080】

[Example]

Next, examples of the present invention will be described.

【0081】

(First Example) FIGS. 7 (a) and 7 (b) are diagrams showing a configuration example of a GaInNAs surface emitting semiconductor laser device according to the first embodiment of the present invention. Note that FIG. 7 (b) is an enlarged view of the active region of FIG. 7 (a).

【0082】

Referring to FIGS. 7 (a) and 7 (b), the surface-emitting semiconductor laser device of this first embodiment is placed on an n-GaAs substrate 301 having a plane orientation (100) of 2 inches in size. N-Al with a thickness of 1/4 times the oscillation wavelength in the medium_xGa_1-xAn n-semiconductor distributed Bragg reflector 302 (lower semiconductor distributed Bragg reflector: also simply referred to as a lower reflector) is formed, which has a periodic structure in which As (x = 0.9) and n-GaAs are alternately laminated for 35 cycles. Then, on the lower reflector 302, the undoped lower GaAs spacer layer 310, 3 layers of Ga_xIn_1-xN_yAs_1-y(x, y) A multiple quantum well active layer 306 composed of a well layer 306a and a GaAs barrier layer 306b, and an undoped upper GaAs spacer layer 311 are formed.

【0083】

A p-semiconductor distributed Bragg reflector 309 (upper semiconductor distributed Bragg reflector: also simply referred to as an upper reflector) is formed on the undoped upper GaAs spacer layer 311. The upper reflector 309 is a 3λ / 4 thick low refractive index layer 340 (λ / 4-15 nm C-doped p-Al) in which AlAs, which is the selected oxide layer, is sandwiched between AlGaAs._xGa_1-xAs (x = 0.9), C-doped p-AlAs Selectable oxide layer 30 nm, 2λ / 4-15 nm C-doped p-Al_xGa_1-xAs (x = 0.9)), GaAs with a thickness of λ / 4 (1 cycle), and C-doped p-Al_xGa_1-xIt is composed of a periodic structure (for example, 25 cycles) in which As (x = 0.9) and p-GaAs are alternately laminated with a thickness of 1/4 times the oscillation wavelength in each medium.

【0084】

In FIG. 7A, reference numeral 312 is a p-side electrode, reference numeral 313 is an n-side electrode, and reference numeral 314 is an insulating film (polyimide).

【0085】

The uppermost GaAs layer 309a of the upper reflector 309 also serves as a contact layer that contacts the electrode 312. The In composition x of the well layer 306a in the active layer 306 was 37%, and the nitrogen composition was 0.5%. The thickness of the well layer 306a was 7 nm. The well layer 306a had a compression strain (high strain) of about 2.5% with respect to the GaAs substrate 301.

【0086】

The raw materials for the GaInNAs active layer 306 by the MOCVD method are TMG (trimethylgallium), TMI (trimethylindium), and AsH.₃(Arsine) was used, and DMHy (dimethylhydrazine) was used as a raw material for nitrogen. In addition, H for carrier gas₂Was used. Since DMHy decomposes at low temperature, it is suitable for low temperature growth such as 600 ° C or less, and is a preferable raw material especially when growing a quantum well layer having a large strain that requires low temperature growth. When the strain is large as in the active layer 306 of the GaInNAs surface emitting semiconductor laser device of the first embodiment, non-equilibrium low temperature growth is preferable. In this first example, the GaInNAs layer was grown at 540 ° C.

【0087】

Further, in this first embodiment, in order to suppress the uptake of oxygen into the active layer 306 and not to reduce the luminous efficiency, the growth of the lower GaAs spacer layer 310 is shown by the broken line in FIG. 7A. Growth was interrupted on the way, and only the substrate to be grown was moved to another chamber, and then Al-based residue in the reaction chamber (growth chamber) was removed using HCl gas. When HCl gas is supplied, the HCl gas can be removed by etching by reacting with the Al-based residue remaining on the side wall of the reaction chamber (growth chamber), the heating zone, the jig holding the substrate, etc. The uptake of oxygen into layer 306 could be suppressed. This step may be performed after the growth of the semiconductor layer containing Al (in the example of FIGS. 7A and 7B, the lower reflector 302) and before the growth of the active layer 306 containing nitrogen.

【0088】

In the fabrication of the surface-emitting semiconductor laser device shown in FIGS. 7 (a) and 7 (b), the lower reflector 302, the lower spacer layer 310, the active layer 306, the upper spacer layer 311, and the upper reflector 309 are sequentially arranged on the substrate 301. After forming the laser, a mesa of a predetermined size is formed by exposing at least the side surface of the p-AlAs selected oxide layer, and the AlAs having the side surface is oxidized from the side surface with water vapor to form Al._xO_yA current narrowing portion was formed. Then, the etching part is embedded with polyimide 314 and flattened, the polyimide on the upper reflector 309 having the p-contact part and the light emitting part is removed, and the p-side electrode 312 is formed in addition to the light emitting part on the p-contact part. Further, the n-side electrode 313 was formed on the back surface of the substrate 301.

【0089】

The oscillation wavelength of the manufactured surface-emitting semiconductor laser device was about 1.3 μm. Further, in this first embodiment, since GaInNAs was used for the active layer 306, a surface emitting semiconductor laser device having a long wavelength band could be formed on the GaAs substrate 301. Further, in the first embodiment, the compound containing Al remaining in the apparatus contained Al remaining in the apparatus so that it would not be taken into the membrane together with oxygen during the growth of the active layer containing nitrogen. Since the compound was excluded using a chlorine-based compound gas, it was possible to prevent oxygen from being mixed with Al in the active layer. As a result, a GaInNAs surface-emitting semiconductor laser device that has high luminous efficiency and oscillates at a low threshold can be manufactured by the MOCVD method, which is advantageous for mass production.

【0090】

In addition, the threshold current was low because the current was narrowed by selective oxidation of the selected oxide layer containing Al and As as main components. According to the current narrowing structure using the current narrowing layer composed of the Al oxide film in which the selected oxide layer is selectively oxidized, the current spreading is suppressed by forming the current narrowing layer close to the active layer, and the current is not exposed to the atmosphere. Carriers can be efficiently confined in a minute area. Further oxidation to form an Al oxide film reduces the refractive index, and the effect of the convex lens makes it possible to efficiently confine light in the minute region where the carrier is confined, which makes it extremely efficient and reduces the threshold current. To. In addition, the manufacturing cost can be reduced because the structure with a narrow current can be easily formed.

【0091】

Conventionally, the MBE method has been mainly used for producing semiconductor layers containing nitrogen such as GaInNAs and other group Vs, but in principle, the amount of raw materials supplied cannot be increased because the semiconductor layers are grown in a high vacuum. Increasing the amount of raw material supplied has the disadvantage of imposing a burden on the exhaust system. That is, although an exhaust pump of a high vacuum exhaust system is required, the throughput is poor because the exhaust system is burdened with the removal of residual raw materials in the MBE chamber and is prone to failure.

【0092】

Specifically, the surface-emitting semiconductor laser device is configured by sandwiching an active region including at least one active layer that generates laser light with a semiconductor multilayer film reflector. While the thickness of the crystal growth layer of the end face emitting laser is about 3 μm, for example, the 1.3 μm wavelength band surface emitting semiconductor laser device requires a thickness of more than 10 μm, but the MBE method requires a high vacuum. Since it is necessary, the raw material supply cannot be increased, and the growth rate is about 1 μm / h. To grow a thickness of 10 μm, the minimum growth interruption time for changing the raw material supply is not provided. It takes 10 hours.

【0093】

The thickness of the active region is usually negligible (less than 10%) compared to the whole, and most are the layers that make up the multilayer reflector. The semiconductor multilayer reflector has a thickness of 1/4 times the oscillation wavelength (thickness of λ / 4) in each medium, and layers of low refractive index and high refractive index are alternately laminated (for example, 20 to 40). Pair) is formed. In the surface emitting semiconductor laser device on the GaAs substrate, an AlGaAs-based material is used, and the Al composition is changed to form a low refractive index layer (large Al composition) and a high refractive index layer (small Al composition). However, in reality, especially on the p side, the resistance increases due to the heterobarrier of each layer, so an intermediate layer with an Al composition between the low refractive index layer and the high refractive index layer is inserted between the low refractive index layer and the high refractive index layer to form a multilayer. The resistance of the membrane reflector is reduced. As described above, the surface emitting semiconductor laser device must grow more than 100 semiconductor layers having different compositions, and is also intermediate between the low refractive index layer and the high refractive index layer of the multilayer film reflector. It is an element that needs to instantly control the amount of raw material supplied, such as by providing a layer.

【0094】

However, in the MBE method, the temperature of the raw material cell is changed to control the amount of raw material supplied, and the composition cannot be controlled flexibly. Therefore, it is difficult to reduce the resistance of the semiconductor multilayer film reflector grown by the MBE method, and the operating voltage is high.

【0095】

On the other hand, the MOCVD method only requires controlling the flow rate of the raw material gas, and the composition can be controlled instantly, does not require a high vacuum like the MBE method, and the growth rate can be increased to, for example, 3 μm / h or more. It is a growth method that is extremely suitable for mass production because the throughput can be easily increased.

【0096】

As described above, according to the first embodiment, it is possible to realize a low power consumption and low cost surface emitting semiconductor laser device in the 1.3 μm band.

【0097】

(Second Example) FIGS. 8A and 8B are diagrams showing a configuration example of a GaInNAs surface emitting semiconductor laser device according to a second embodiment of the present invention. Note that FIG. 8 (b) is an enlarged view of the active region of FIG. 8 (a). Further, in FIGS. 8 (a) and 8 (b), the same reference numerals are given to the same parts as those in FIGS. 7 (a) and 7 (b).

【0098】

The difference between this second embodiment and the first embodiment described above is that the step of removing the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber of the lower reflector 302 is performed. That's what you're doing in the area. The low refractive index layer that constitutes the lower reflector 302 is mostly composed of AlGaAs (specifically, most of the lower reflector 302 is Al._0.9Ga_0.1The As layer and the GaAs layer are alternately laminated), and the layer 302a on the most active layer 306 side is Ga._xIn_1-xP_yAs_1-y(For example, x = 0.5, y = 1), growth is interrupted in the middle of the GaAs layer, which is the high refractive index layer below it, and only the substrate to be grown is moved to another chamber, and then HCl gas is transferred to the reaction chamber (growth chamber). ) Was supplied to exclude Al-based residues in the reaction chamber.

【0099】

The oscillation wavelength of the manufactured surface-emitting semiconductor laser device was about 1.3 μm. Moreover, since GaInNAs was used as the active layer, a surface-emitting semiconductor laser device in a long wavelength band could be formed on a GaAs substrate.

【0100】

In addition, the nitrogen-containing activity after growing the Al-containing semiconductor layer so that the Al-containing compound remaining in the apparatus is not taken into the film together with oxygen during the growth of the nitrogen-containing active layer. Since HCl, which is an etching gas, was supplied before the layer was grown, the compound containing Al remaining in the reaction chamber (growth chamber) was excluded before the active layer was grown, and oxygen was added to the active layer. It was possible to suppress the mixing with the compound. However, an oxide film due to the growth interruption is formed at the interface where the growth is interrupted, and defects may occur. This can result in the formation of non-luminescent recombination centers.

【0101】

However, in the second embodiment, the GaInPAs layer 302a, which is a wide band gap, is inserted between the growth-interrupted interface and the GaInNAs active layer 306, so that the carrier is surely injected into the growth-interrupted interface. It can be suppressed and the decrease in luminous efficiency due to the non-luminescent recombination center at the growth interruption interface can be prevented. In the second embodiment, the GaInPAs layer has a lattice matching composition, but when the active layer 306 has a high compression strain composition as in this second embodiment, the GaInPAs layer 302a has a tensile strain composition. It is preferable because it has the effect of compensating for the strain of the active layer 306 and can suppress the lattice relaxation of the active layer 306.

【0102】

As a result, a GaInNAs surface-emitting semiconductor laser device with high luminous efficiency and oscillating at a low threshold value could be manufactured by the MOCVD method, which is advantageous for mass production.

【0103】

(Third Example) FIGS. 9 (a) and 9 (b) are diagrams showing a configuration example of a GaInNAs surface emitting semiconductor laser device according to a third embodiment of the present invention. Note that FIG. 9 (b) is an enlarged view of the active region of FIG. 9 (a). Further, in FIGS. 9 (a) and 9 (b), the same reference numerals are given to the same parts as those in FIGS. 7 (a), (b) and 8 (a) and 8 (b).

【0104】

The difference between this third embodiment and the second embodiment described above is that in this third embodiment, the Al raw material or Al reactant remaining in the growth chamber, or the Al compound, or Al is used. The removal process constitutes the low refractive index layer of the lower reflector 302._xIn_1-xP_yAs_1-y(For example, x = 0.5, y = 1) It is in the layer 302a, the growth is interrupted during the growth of the GaInPAs layer 302a, only the substrate to be grown is moved to another chamber, and then the HCl gas is transferred to the reaction chamber (growth). It was supplied to the chamber) to exclude Al-based residues.

【0105】

The oscillation wavelength of the manufactured surface-emitting semiconductor laser device was about 1.3 μm. Moreover, since GaInNAs was used as the active layer, a surface-emitting semiconductor laser device in a long wavelength band could be formed on a GaAs substrate.

【0106】

Further, Al, which is an etching gas, is supplied so that the compound containing Al remaining in the apparatus is not taken into the membrane together with oxygen when the active layer containing nitrogen grows, and the Al remaining in the apparatus is supplied. The compound containing was removed. As a result, it was possible to prevent oxygen from being mixed with Al in the active layer.

【0107】

Further, in this third embodiment, since there is a GaInPAs layer 302a having a wide band gap between the growth interruption interface and the GaInNAs active layer, it is possible to prevent a decrease in luminous efficiency due to the non-emission recombination center.

【0108】

As a result, a GaInNAs surface-emitting semiconductor laser device with high luminous efficiency and oscillating at a low threshold value could be manufactured by the MOCVD method, which is advantageous for mass production.

【0109】

(Fourth Example) FIGS. 10 (a) and 10 (b) are diagrams showing a configuration example of a GaInNAs surface emitting semiconductor laser device according to a fourth embodiment of the present invention. Note that FIG. 10 (b) is an enlarged view of the active region of FIG. 10 (a). Further, in FIGS. 10 (a) and 10 (b), the same reference numerals are given to the same parts as those in FIGS. 7 (a), (b), 8 (a), (b) and 9 (a), (b). Is attached.

【0110】

The difference between this fourth embodiment and the first embodiment described above is that, in this fourth embodiment, the Al raw material, the Al reactant, the Al compound, or Al remaining in the growth chamber is used. The process of removing is in the GaPAs layer 320 formed in the resonator part, the growth is interrupted during the growth of the GaPAs layer 320, only the substrate to be grown is moved to another chamber, and then the HCl gas is transferred to the reaction chamber (growth). It was supplied to the chamber) to exclude Al-based residues.

【0111】

Specifically, in this fourth embodiment, the GaPAs layer 320 is formed on the uppermost AlGaAs low refractive index layer 302a of the lower reflector 302, and the Al-based residue is excluded during the growth of the GaPAs layer 320. did. An Al-based residue may be excluded by forming a GaAs layer between the AlGaAs low refractive index layer 302a and the GaPAs layer 320.

【0112】

The oscillation wavelength of the manufactured surface-emitting semiconductor laser device was about 1.3 μm. Moreover, since GaInNAs was used as the active layer, a surface-emitting semiconductor laser device in a long wavelength band could be formed on a GaAs substrate.

【0113】

Further, between the semiconductor layer containing Al and the active layer containing nitrogen so that the compound containing Al remaining in the apparatus is not taken into the film together with oxygen during the growth of the active layer containing nitrogen. Since HCl, which is an etching gas, was supplied in the above, the compound containing Al remaining in the reaction chamber (growth chamber) was excluded before the active layer was grown, and oxygen was suppressed from being mixed with Al in the active layer. I was able to. However, an oxide film due to the growth interruption is formed at the interface where the growth is interrupted, and defects may occur. This can result in the formation of non-luminescent recombination centers.

【0114】

However, in the fourth embodiment, the GaPAs layer 320, which has a wider bandgap than the GaAs spacer layer, is inserted between the growth-interrupted interface and the GaInNAs active layer 306, so that the carrier is surely injected into the growth-interrupted interface. It is possible to prevent the light emission efficiency from being lowered by the non-emission recombination center at the growth interruption interface. The GaPAs layer 320 has tensile strain with respect to the GaAs substrate 301. When the active layer 306 has a high compression strain composition as in this fourth embodiment, if the GaPAs layer 320 has tensile strain, it has an effect of compensating for the strain of the active layer 306, and the active layer 306 has a strain. It is preferable because it can suppress lattice relaxation. In this fourth embodiment, the GaPAs layer 320 is provided, but instead of this, a GaInP layer and a GaInPAs layer may be provided.

【0115】

As a result, a GaInNAs surface-emitting semiconductor laser device with high luminous efficiency and oscillating at a low threshold value could be manufactured by the MOCVD method, which is advantageous for mass production.

【0116】

(Fifth Example) FIG. 11 is a diagram showing a fifth embodiment of the present invention, and FIG. 11 shows an optical transmission module in which a surface emitting semiconductor laser device of the second embodiment and a fiber are combined. Is outlined.

【0117】

In the optical transmission module of the fifth embodiment, the laser light from the GaInNAs surface emitting semiconductor laser element in the 1.3 μm band is input to the quartz optical fiber and transmitted. In this case, it is possible to increase the transmission speed by arranging a plurality of surface emitting semiconductor laser elements having different oscillation wavelengths in a one-dimensional or two-dimensional array and performing wavelength division multiplexing transmission. It is also possible to arrange surface-emitting semiconductor laser elements in a one-dimensional or two-dimensional array and combine them with an optical fiber bundle composed of a plurality of optical fibers corresponding to each to increase the transmission speed.

【0118】

Further, when the surface emitting semiconductor laser element according to the present invention is used in an optical communication system, a low-cost and highly reliable optical transmission module can be realized, and a low-cost and highly reliable optical communication system can be realized. Further, since the surface emitting semiconductor laser device using GaInNAs has good temperature characteristics and a low threshold value, it is possible to realize a system that generates less heat and can be used up to a high temperature without cooling.

【0119】

(Sixth Example) FIG. 12 is a diagram showing a sixth embodiment of the present invention, and FIG. 12 shows a surface emitting semiconductor laser device of the third embodiment, a receiving photodiode, and an optical fiber. The outline of the optical transmission / reception module in combination with and is shown.

【0120】

When the surface-emitting semiconductor laser device according to the present invention is used in an optical communication system, the surface-emitting semiconductor laser device has a low cost. Therefore, as shown in FIG. 12, the surface-emitting semiconductor laser device for transmission (1.3 μm band GaInNAs) A low-cost and highly reliable optical communication system can be realized by using an optical transmission / reception module that combines a surface-emitting semiconductor laser device), a receiving photodiode, and an optical fiber. Further, in the case of the surface emitting semiconductor laser device using GaInNAs according to the present invention, the temperature characteristics are good, the operating voltage is low, and the threshold value is low, so that heat generation is small and there is no cooling to a high temperature. It is possible to realize a lower cost system that can be used in.

【0121】

Furthermore, by combining fluoridated POF (plastic fiber), which has low loss in a long wavelength band such as 1.3 μm, and a surface emitting laser that uses GaInNAs as the active layer, the cost of the fiber is low and the diameter of the fiber is reduced. Since it is large, easy to couple with the fiber, and the mounting cost can be reduced, an extremely low cost module can be realized.

【0122】

The optical communication system using the surface emitting semiconductor laser device according to the present invention can be used not only for long-distance communication using optical fibers, but also for transmission between devices such as computers such as LAN (Local Area Network), and further. It can be used for short-distance communication as an optical interconnection such as data transmission between boards, LSIs in boards, and elements in LSIs.

【0123】

Although the processing performance of LSIs and the like has improved in recent years, the transmission speed of the parts connecting them will become a bottleneck in the future. When changing the signal connection in the system from the conventional electrical connection to the optical interconnect, for example, the optical transmission module and the optical transmission / reception module according to the present invention are used between the boards of the computer system, between the LSIs in the boards, and between the elements in the LSIs. When connected, an ultra-high-speed computer system becomes possible.

【0124】

Further, when a plurality of computer systems and the like are connected by using the optical transmission module and the optical transmission / reception module according to the present invention, an ultra-high-speed network system can be constructed. In particular, a surface-emitting semiconductor laser device is suitable for a parallel transmission type optical communication system because it can reduce power consumption by an order of magnitude and can be easily formed into a two-dimensional array as compared with an end-face emitting laser.

【0125】

As described above, according to the GaInNAs-based material, which is a semiconductor layer containing nitrogen, the Al (Ga) As / (Al) GaAs-based material, which has a proven track record in 0.85 μm band surface emission type semiconductor laser devices using a GaAs substrate, etc. A semiconductor multilayer film distribution Bragg reflector and a current narrowing structure by selective oxidation of AlAs can be applied. By manufacturing a surface-emitting semiconductor laser device by the manufacturing method according to the present invention, the crystal quality of the GaInNAs active layer can be improved and the multilayer structure can be improved. Since it is possible to reduce the resistance of the film reflector and improve the crystal quality and controllability of the multilayer film structure as a surface-emitting semiconductor laser device, it is possible to improve the practical level of high-performance long-wavewave band surface-emitting semiconductors such as the 1.3 μm band. Laser elements can be realized, and by using these elements, optical communication systems such as low-cost optical fiber communication systems and optical interconnection systems that do not require cooling elements can be realized.

【0126】

[Effect of the invention]

As described above, according to the inventions of claims 1 to 3, in a method for manufacturing a semiconductor light emitting device in which a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen, Al is contained. After growing the semiconductor layer and before starting the growth of the active layer containing nitrogen, a chlorine-based compound gas is supplied to the growth chamber as an etching gas, and the Al raw material or Al reaction product remaining in the growth chamber is supplied. , Or, since the Al compound or Al is removed, the uptake of oxygen into the active layer can be suppressed, and a semiconductor light emitting device having high light emission efficiency can be obtained.

【0127】

In particular, according to the invention according to claim 2, in the method for producing a semiconductor light emitting device according to claim 1, the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber is removed. Since the step of interrupting the growth of the semiconductor light emitting device is performed after the substrate to be grown of the semiconductor light emitting element is moved from the growth chamber to another chamber or once taken out to the outside, the substrate to be grown is subjected to etching or the like. It is possible to suppress the uptake of oxygen into the active layer without being damaged, and it is possible to obtain a semiconductor light emitting device having high light emission efficiency.

【0128】

Further, according to the invention of claim 3, in the method for manufacturing a semiconductor light emitting device according to claim 1, the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber is etched. After performing the step of removing with a chlorine-based compound gas as a gas and before growing the active layer containing nitrogen, the GaInP layer, the GaPAs layer, or the GaInPAs layer is formed, so that the growth interrupting interface Injecting carriers into the aluminum are almost eliminated, and a decrease in light emission efficiency can be prevented. That is, when a material having a bandgap energy higher than the bandgap energy of the surface material at the time of growth interruption is grown between the active layer containing nitrogen, the injection carriers to the growth interruption interface are almost eliminated, so that the luminous efficiency is lowered. Can be prevented. Further, in the case of a semiconductor laser, the threshold current can be made sufficiently low.

【0129】

Further, according to the invention of claim 4, a semiconductor light emitting device having high luminous efficiency can be obtained because it is manufactured by the method for manufacturing a semiconductor light emitting device according to any one of claims 1 to 3. Can be done.

【0130】

Further, according to the invention of claim 5, an active region including at least one nitrogen-containing active layer that generates laser light and an upper portion and a lower portion of the active layer for obtaining laser light are obtained on the semiconductor substrate. In a method for manufacturing a surface emitting semiconductor laser element having a top reflector and a lower reflector provided in the above and a resonator structure sandwiched between the upper reflector and the lower reflector, the lower reflector has a refractive index. Has a semiconductor distributed Bragg reflector that periodically changes and reflects incident light by light wave interference, and the layer with a small refractive index of the semiconductor distributed Bragg reflector is Al._xGa_1-xThe layer consisting of As (0 &lt;x 1) and having a large refractive index of the semiconductor distributed Bragg reflector is Al._yGa_1-yAfter growing the lower reflector containing As (0 y &lt;x 1) and before growing the active layer containing nitrogen, a chlorine-based compound gas was introduced into the growth chamber as an etching gas. Since it is supplied and the Al raw material or Al reaction product, Al compound, or Al remaining in the growth chamber is removed, it is possible to suppress the uptake of oxygen into the active layer, and the drive voltage is low. A surface-emitting semiconductor laser device having low voltage, high emission efficiency, low threshold current operation, and good temperature characteristics can be easily realized at low cost.

【0131】

Further, according to the inventions of claims 6 and 7, after performing a step of removing the Al raw material, the Al reaction product, the Al compound, or Al remaining in the growth chamber with an etching gas, Since the GaInP layer, the GaPAs layer, or the GaInPAs layer is grown before the active layer is grown, the decrease in luminous efficiency can be suppressed, and the characteristics of high luminous efficiency and small threshold current can be obtained.

【0132】

Further, according to the invention of claim 8, the active layer is deprived of oxygen because it is produced by the method for manufacturing a surface emitting semiconductor laser device according to any one of claims 5 to 7. A surface-emitting semiconductor laser device having low resistance, low drive voltage, high emission efficiency, low threshold current operation, and good temperature characteristics can be easily realized at low cost.

【0133】

Further, according to the invention of claim 9, by using the surface emitting semiconductor laser element of claim 8 as a light source, a low-cost optical transmission module that does not require a cooling element can be realized.

【0134】

Further, according to the invention of claim 10, by using the surface emitting semiconductor laser element of claim 8 as a light source, a low-cost optical transmission / reception module that does not require a cooling element can be realized.

【0135】

Further, according to the invention of claim 11, by using the surface emitting semiconductor laser element of claim 8 as a light source, an optical communication system such as a low-cost optical fiber communication system or an optical interconnection system that does not require a cooling element is used. Can be realized.

[Simple explanation of drawings]

[Figure 1]

It is a figure which shows the nitrogen composition dependence of the threshold current density experimentally obtained by the inventor of this application.

[Figure 2]

It is a figure which shows the outline of the general MOCVD apparatus.

[Fig. 3]

It is a figure which shows the room temperature photoluminescence spectrum from the active layer which consists of the GaInNAs quantum well layer which is the semiconductor layer containing nitrogen, which is the semiconductor layer with MOCVD, and the GaInNAs / GaAs 2 weight well structure which consists of a GaAs barrier layer.

[Fig. 4]

It is a figure which shows the basic structure of a sample.

[Fig. 5]

As an example of the semiconductor light emitting device shown in FIG. 4, an element having a clad layer made of AlGaAs, an intermediate layer made of GaAs, and an active layer having a GaInNAs / GaAs2 weight well structure is used by one epitaxial growth device (MOCVD). It is a figure which shows the distribution in the depth direction of a nitrogen (N) concentration and an oxygen (O) concentration at the time of formation.

[Fig. 6]

It is a figure which shows the depth direction distribution of Al concentration in the same sample as FIG.

[Fig. 7]

It is a figure which shows the structural example of the GaInNAs surface emission type semiconductor laser element of 1st Example of this invention.

[Fig. 8]

It is a figure which shows the structural example of the GaInNAs surface emitting semiconductor laser element of the 2nd Example of this invention.

[Fig. 9]

It is a figure which shows the structural example of the GaInNAs surface emitting semiconductor laser element of the 3rd Example of this invention.

[Fig. 10]

It is a figure which shows the structural example of the GaInNAs surface emitting semiconductor laser element of the 4th Example of this invention.

[Fig. 11]

It is a figure which shows the 5th Example of this invention.

[Fig. 12]

It is a figure which shows the 6th Example of this invention.

[Explanation of symbols]

301 n-GaAs substrate 302 Lower reflector 310 Lower spacer layer 306 active layer 311 Upper spacer layer 312 p side electrode 313 n side electrode 314 polyimide 302a GaIn PAs layer 320 GaPAs layer