Method and apparatus for manufacturing semiconductor light emitting element, optical transmission module, optical transmission and receiving module and optical communication system

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

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

【0002】

[Conventional technology]

As represented by the Internet, the amount of information handled by optical communication has increased dramatically due to the explosive spread of networks in recent years, and it is expected that it will continue to increase thereafter. For this reason, optical fibers have been introduced not only for trunk lines, but also for metro networks, transmission lines close to users such as subscriber systems such as general homes and offices, and LANs (Local Area Networks), as well as wiring between devices and within devices. Is being done. For this reason, large-capacity information transmission technology using light has become extremely important.

【0003】

In order to promote the spread of optical fibers and optical wiring in networks closer to end users, a light source that is cheaper, smaller, and has good consistency with optical fibers is required. As such a light source, a vertically cavity surface emitting semiconductor laser device (VCSEL) with a small transmission loss of silica fiber and good consistency in the 1.3 μm band and 1.55 μm band (VCSEL: Vertical Cavity Surface Emitting Laser) Is extremely promising. Compared to end-face emitting lasers, surface-emitting semiconductor laser devices are suitable for lower cost, lower power consumption, smaller size, and two-dimensional integration, and are already high-speed LANs in the 0.85 μm band that can actually be formed on a GaAs substrate. It has been put to practical use with 1 Gbit / s Ethernet (registered trademark).

【0004】

At present, the material system on the InP substrate is generally used in the 1.3 μm band, and is used in the end face emitting semiconductor laser. However, these conventional long-wavelength semiconductor lasers have a major drawback that the operating current increases three times due to the temperature characteristics when the environmental temperature rises from room temperature to 80 ° C. Therefore, consideration is given to cooling means and the like. This is a factor that causes high costs. Further, in a surface emitting semiconductor laser device, since there is no material suitable for a reflecting mirror, it is difficult to improve the performance, and the current situation is that practical level characteristics have not been obtained. It has also been proposed to use GaAs / AlGaAs reflectors for the active layer on the InP substrate, but there are many problems in mass production due to the high cost.

【0005】

Therefore, recently, a material system capable of forming a 1.3 μm band on a GaAs substrate has been attracting attention. Among these material systems, GaInNAs is attracting attention as a material that can extremely reduce the temperature dependence of laser characteristics. That is, GaInNAs are considered to be promising as a light source for medium-scale or smaller optical networks because the cooling mechanism can be simplified, the size can be reduced, and the cost can be reduced because the temperature dependence is small. GaInNAs narrows the bandgap by containing N inside the crystal, and the technology to grow the active layer containing N with high quality is very important.

【0006】

Conventionally, Japanese Patent Application Laid-Open No. 10-126004 improves that when a GaInNAs active layer and a layer containing Al are directly contacted and grown, nitrogen segregates at the interface, the surface morphology deteriorates, and the emission intensity is significantly lowered. As a method, a structure has been proposed in which the layer in direct contact with the GaInNAs layer does not contain Al.

【0007】

Further, in Japanese Patent Application Laid-Open No. 2000-4068, crystallinity and luminous efficiency are improved by providing an intermediate layer that does not contain Al and N as constituent elements between the GaInNP active layer and the AlGaInP clad layer.

【0008】

However, it has been reported that the luminous efficiency of the GaInNAs active layer formed on the semiconductor layer containing Al is lowered even when the intermediate layer is provided. That is, according to the document "Electoron. Lett., 2000, 36 (21), pp1776-1777", when the GaInNAs quantum well layer is continuously grown on the AlGaAs clad layer in the same MOCVD growth chamber, the photoluminescence strength is significantly deteriorated. It has been reported to do. In the above document, the AlGaAs clad layer and the GaInNAs active layer are grown in different MOCVD growth chambers in order to improve the photoluminescence strength.

【0009】

[Problems to be Solved by the Invention]

FIG. 1 is a diagram showing a room temperature photoluminescence spectrum of a GaInNAs / GaAs2 weight well structure composed of a GaInNAs quantum well layer and a GaAs barrier layer produced by the MOCVD apparatus by the inventor of the present application. In FIG. 1, reference numeral A indicates 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 indicates a sample in which a GaAs intermediate layer is sandwiched on a GaInP clad layer. Shows a sample in which a double-heavy well structure is continuously formed.

【0010】

As shown in FIG. 1, the photoluminescence intensity of sample A is reduced to less than half that of sample B. From this, when 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 active layer is formed as in the conventional example. It can be seen that there is a problem that the light emission intensity of the aluminum is deteriorated. Therefore, there is a problem that the threshold current density of the GaInNAs-based laser formed on the AlGaAs clad layer is more than twice as high as that when it is formed on the GaInP clad layer.

【0011】

The present invention is a method for manufacturing a semiconductor light emitting device and a semiconductor light emitting device capable of remarkably improving the light emitting characteristics in a semiconductor light emitting device in which a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen. It is an object of the present invention to provide a manufacturing apparatus, an optical transmission module, an optical transmission / reception module, and an optical communication system.

【0012】

[Means for solving problems]

In order to achieve the above object, in the invention according to claim 1, a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen, and the active layer containing nitrogen and the semiconductor layer containing Al are provided. In the method for manufacturing a semiconductor light emitting device to be grown using a nitrogen compound raw material and an organic metal Al raw material, respectively, when the susceptor holding the substrate when growing the semiconductor layer containing Al and the active layer containing nitrogen are grown. It is characterized in that it is different from the susceptor that holds the substrate.

【0013】

Further, in the invention according to claim 2, a semiconductor layer containing Al is provided between the substrate and the active layer containing nitrogen, and the active layer containing nitrogen and the semiconductor layer containing Al are provided as a nitrogen compound raw material and an organic material, respectively. In a semiconductor light emitting device manufacturing apparatus that grows using a metallic Al raw material, a susceptor that holds a substrate when growing the semiconductor layer containing Al and a susceptor that holds a substrate when growing the active layer containing nitrogen. Is characterized by being different from.

【0014】

Further, in the invention according to claim 3, in the semiconductor light emitting device manufacturing apparatus according to claim 2, the susceptor for growing the active layer containing nitrogen while growing the semiconductor layer containing Al is a separate chamber from the growth chamber. After the growth of the semiconductor layer containing Al is completed, the susceptor for growing the active layer containing nitrogen and the susceptor for growing the semiconductor layer containing Al are separated from each other without exposing the substrate to the atmosphere. It is characterized by having a replaceable structure.

【0015】

Further, in the invention according to claim 4, a semiconductor layer containing Al is provided between the substrate and the active layer containing nitrogen, and the active layer containing nitrogen and the semiconductor layer containing Al are provided as a nitrogen compound raw material and an organic material, respectively. In the method for manufacturing a semiconductor light emitting device to be grown using a metal Al raw material, the susceptor holding the substrate has a removable cover that covers a portion other than the portion that directly holds the substrate, and the semiconductor layer containing the Al is contained. It is characterized in that a cover is attached when the active layer is grown, and the cover is removed when the active layer containing nitrogen is grown.

【0016】

Further, in the invention according to claim 5, a semiconductor layer containing Al is provided between the substrate and the active layer containing nitrogen, and the active layer containing nitrogen and the semiconductor layer containing Al are provided as a nitrogen compound raw material and an organic material, respectively. In a semiconductor light emitting device manufacturing apparatus that grows using a metallic Al raw material, the susceptor that holds the substrate has a removable cover that covers a portion other than the portion that directly holds the substrate, and the semiconductor layer containing the Al. It is characterized by having a mechanism of attaching a cover when growing the semiconductor and removing the cover when growing the active layer containing nitrogen.

【0017】

Further, according to the invention of claim 6, in the semiconductor light emitting device manufacturing apparatus according to claim 5, the removable cover has a mechanism which can be attached and detached in a state where the susceptor is loaded in the reaction chamber. It is characterized by.

【0018】

The invention according to claim 7 is the method for manufacturing a semiconductor light emitting device according to claim 1 or 4, or the semiconductor light emitting device according to claim 2 or 3, or claim 5 or 6. It is a surface-emitting semiconductor laser device characterized by being manufactured by the manufacturing apparatus of.

【0019】

The invention according to claim 8 is an optical transmission module characterized in that the surface emitting semiconductor laser device according to claim 7 is used.

【0020】

The invention according to claim 9 is an optical transmission / reception module characterized in that the surface emitting semiconductor laser device according to claim 7 is used.

【0021】

The invention according to claim 10 is an optical communication system characterized in that the surface emitting semiconductor laser device according to claim 7 is used.

【0022】

BEST MODE FOR CARRYING OUT THE INVENTION

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

【0023】

FIG. 2 is a diagram showing an example of a semiconductor light emitting device in which a semiconductor layer containing Al is provided between a substrate and a semiconductor layer containing nitrogen. In the semiconductor light emitting device of FIG. 2, the first semiconductor layer 202 containing Al, the intermediate layer 203, the active layer 204 containing nitrogen, the intermediate layer 203, and the second semiconductor layer 205 are formed on the substrate 201. They are stacked sequentially.

【0024】

Here, as the substrate 201, for example, a compound semiconductor substrate such as GaAs, InP, GaP or the like is used.

【0025】

Further, for the first semiconductor layer 202 containing Al as a constituent element, materials such as AlAs, AlP, AlGaAs, AlInP, AlGaInP, AlInAs, AlInAsP, and AlGaInAsP can be used. The first semiconductor layer 202 is not limited to a single layer, but may be a stack of a plurality of semiconductor layers containing Al as a constituent element.

【0026】

Further, the intermediate layer 203 does not contain Al as a constituent element, and is composed of, for example, a material such as GaAs, GaP, InP, GaInP, GaInAs, GaInAsP.

【0027】

Further, for the active layer 204 containing nitrogen, for example, materials such as GaNAs, GaPN, GaInNAs, GaInNP, GaNAsSb, GaInNAsSb are used, and the active layer 204 containing nitrogen grows crystal without intentionally introducing an Al raw material. Has been done. Further, the active layer 204 can be configured not only in the case of a single layer but also in a multiple quantum well structure in which a semiconductor containing nitrogen is used as a well layer and an intermediate layer material is used as a barrier layer.

【0028】

The energy band gap of each layer of the semiconductor light emitting device in FIG. 2 increases in the order of the active layer 204, the intermediate layer 203, the first semiconductor layer 202, and the second semiconductor layer 205. The second semiconductor layer 205 is generally made of the same material as the first semiconductor layer 202, but it does not necessarily have to be the same material, and is made of a material that does not contain Al. It is also possible.

【0029】

The semiconductor light emitting device of FIG. 2 can undergo crystal growth using an epitaxial growth apparatus using an organometallic Al raw material and a nitrogen compound raw material. Here, for example, TMA and TEA can be used as the organometallic Al raw material. In addition, as raw materials for nitrogen compounds, organic nitrogen raw materials such as DMHy and MMHy and NH₃Can be used. Moreover, as a crystal growth method, a MOCVD method or a CBE method can be used.

【0030】

As an example of the semiconductor light emitting device of FIG. 2, FIG. 3 shows that the first semiconductor layer 202 and the second semiconductor layer 205 are AlGaAs, the intermediate layer 203 is GaAs, and the active layer 204 containing nitrogen is a GaInNAs / GaAs2 weight element. It is a figure which shows the distribution in the depth direction of the nitrogen (N) concentration and the oxygen (O) concentration when the semiconductor light emitting device configured as a well structure is formed by using one epitaxial growth apparatus (MOCVD). This measurement was performed by SIMS. The following table (Table 1) shows the measurement conditions.

【0031】

[table 1]

<img file="JP2003174235A_D0001.tif" />【0032】

In FIG. 3, two nitrogen concentration peaks are found in the active layer 204, corresponding to the GaInNAs / GaAs2 weight well structure. Then, a peak of oxygen concentration is detected in the active layer 204. However, the oxygen concentration in the intermediate layer 203 containing no Al is about an order of magnitude lower than the oxygen concentration in the active layer 204.

【0033】

On the other hand, the oxygen concentration of the semiconductor light emitting device in which the first semiconductor layer 202 and the second semiconductor layer 205 are GaInP, the intermediate layer 203 is GaAs, and the active layer 204 containing nitrogen is a GaInNAs / GaAs2 weight well structure. The oxygen concentration in the active layer 204 was at the background level when the distribution in the depth direction of was measured.

【0034】

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) lowers 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 to be the cause.

【0035】

The mechanism by which oxygen is taken up is considered as follows. That is, when a semiconductor layer containing Al as a constituent element is grown, an Al raw material, an Al reaction product, an Al compound, or Al remains in the growth chamber. After that, when the nitrogen compound raw material is supplied to the growth chamber when the semiconductor layer containing nitrogen is crystal-grown, impurities such as water contained in the nitrogen compound raw material or the nitrogen compound raw material and a chemically active Al raw material or a chemically active Al raw material or , Al reaction product, Al compound, or Al chemically bond with Al, and Al is incorporated into the active layer. In addition, Al reacts with the water contained in the nitrogen compound raw material, and oxygen impurities are also taken into the active layer at the same time, which lowers the luminous efficiency of the active layer.

【0036】

As described above, the residue of the substance containing Al in the growth chamber, the impurities such as water contained in the nitrogen compound raw material or the nitrogen compound raw material, and the residual substance containing Al are combined and incorporated into the active layer. However, it was found that this is a factor in the manufacturing process that lowers the light emission efficiency in the semiconductor light emitting device in which the semiconductor layer containing Al is provided between the substrate and the active layer containing nitrogen.

【0037】

The present invention intends to solve such factors in the manufacturing process and to form an active layer containing nitrogen having high luminous efficiency on the semiconductor layer containing Al.

【0038】

First Embodiment As described above, in the case of manufacturing a semiconductor light emitting device in which a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen, the residual substance containing Al in the growth contributes to a decrease in luminous efficiency. Therefore, preventing this is effective for improving the luminous efficiency. For example, in the MOCVD method, the gas flow of the raw material is blown onto the substrate, so the susceptor near the substrate, especially adjacent to the substrate, is easily exposed to the raw material gas and substances generated by the reaction on the substrate, resulting in Al. There is a high risk that the contained substances will be adsorbed and remain. In addition, the substance containing Al adsorbed on the susceptor reacts with the nitrogen compound raw material and impurities contained therein (for example, mainly water in the case of DMHy) because it is close to the substrate when growing the active layer containing nitrogen. There is an extremely high risk of being taken up by the active layer. Therefore, it is necessary to prevent the substance containing Al adsorbed on the susceptor from being taken in by reacting with the substance containing Al adsorbed on the susceptor when the active layer containing nitrogen grows. It can be said that it is extremely effective in preventing the decrease in the amount of nitrogen.

【0039】

FIG. 4 is a diagram showing a configuration example of a semiconductor light emitting device manufacturing apparatus according to the first embodiment of the present invention. Note that FIG. 4 is a diagram showing a vertical cross section of the reaction chamber (growth chamber) of the MOCVD apparatus.

【0040】

In the configuration example of FIG. 4, the reaction chamber is a vertical reaction tube, and a substrate for growing a semiconductor light emitting element and a susceptor for mounting the substrate are held on the stage inside. The raw material gas introduced from the raw material gas supply port is introduced onto the substrate. The stage is provided with a heating mechanism by resistance heating, and the raw material gas chemically reacts on the surface of the substrate on the susceptor heated to a high temperature by the heating mechanism of this stage to grow a semiconductor layer.

【0041】

Here, as shown in FIG. 5, the susceptor can be attached and detached from the stage, and after the stage is pulled out from the reaction chamber to the second chamber for transport, the susceptor and the substrate mounted on the susceptor are transported together. It can be taken out through the sample chamber. Each chamber can be partitioned by, for example, a gate valve, and the sample chamber can be independently evacuated or purged with hydrogen or nitrogen. As a result, for example, the susceptor and the substrate can be transported to the reaction chamber in a hydrogen atmosphere.

【0042】

Multiple susceptors are prepared in the sample chamber, and as shown in Fig. 6 (a), a thin pole extends from a small hole in the lower part of the susceptor to lift the substrate, and the substrate is used for transporting the substrate. The arm allows you to move freely between the susceptors. The transfer mechanism of this substrate does not have to be only an arm, and it is also possible to use a transfer method using a vacuum chuck or the like as shown in FIG. 6 (b), for example.

【0043】

The susceptor in the sample chamber can transport any susceptor to the reaction chamber. That is, the substrate can move on an arbitrary susceptor without exposing the substrate to the outside air in the sample chamber, and the arbitrary susceptor can be transported to the reaction chamber. Since it is not necessary to expose the substrate to the outside air during transportation, the substrate is minimized from contamination and oxidation by oxygen in the atmosphere.

【0044】

In the first embodiment, the semiconductor light emitting device of FIG. 2 can be grown by the following steps. That is, first, the first semiconductor layer 202 containing Al is grown on the substrate 201. After completing the step of growing the semiconductor layer 202 containing Al, the susceptor on which the substrate is placed is transported to the sample chamber, and the substrate is moved onto another susceptor prepared in the sample chamber in advance. The susceptor prepared in the sample chamber is sufficiently evacuated in advance to remove the adsorbed gas, and when transporting, for example, purging with hydrogen gas can prevent contamination and oxidation of the substrate and susceptor. You can. The substrate mounted on the new susceptor is transported to the reaction chamber together with the susceptor, and the intermediate layer 203 and the active layer 204 are subsequently grown. Then, the second semiconductor layer 205 including the intermediate layer 203 and Al is grown. At this time, the timing for replacing the susceptor may be between the growth of the first semiconductor layer 202 containing Al and the end of the growth of the lower intermediate layer 203. For example, the growth of the lower intermediate layer 203 may occur. Growth may be interrupted on the way and the susceptor may be replaced.

【0045】

By using the above-mentioned step of exchanging the susceptor, it is possible to use a susceptor without adsorption instead of the susceptor adsorbed with a substance containing Al when growing the active layer. As a result, it is possible to prevent the substance containing Al from coming into contact with the nitrogen compound raw material or the impurities contained in the nitrogen compound raw material and being taken into the active layer, and it is possible to grow a semiconductor light emitting device having a low threshold value.

【0046】

In other words, in the method for manufacturing a semiconductor light emitting device and the manufacturing apparatus for a semiconductor light emitting device according to the first embodiment, a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen, and the active layer containing nitrogen is provided. When the semiconductor layer containing Al and the semiconductor layer containing Al is grown using the nitrogen compound raw material and the organic metal Al raw material, respectively, the susceptor holding the substrate when growing the semiconductor layer containing Al and the active layer containing nitrogen. It shall be different from the susceptor that holds the substrate as it grows.

【0047】

As a result, it is possible to prevent the substance containing Al from coming into contact with the nitrogen compound raw material or the impurities contained in the nitrogen compound raw material and being taken into the active layer, and it is possible to grow a semiconductor light emitting device having a low threshold value.

【0048】

Then, in the semiconductor light emitting device manufacturing apparatus of the first embodiment, while the semiconductor layer containing Al is growing, the susceptor for growing the active layer containing nitrogen is kept on standby in a room separate from the growth chamber, and Al After the growth of the semiconductor layer containing Al is completed, the susceptor for growing the active layer containing nitrogen is exchanged with the susceptor for growing the semiconductor layer containing Al without exposing the substrate to the atmosphere. There is.

【0049】

FIG. 10 is a diagram showing a modified example of the semiconductor light emitting device manufacturing apparatus according to the first embodiment of the present invention. Note that FIG. 10 is a schematic view of the vertical cross section of the reaction chamber of the MOCVD apparatus as viewed from the side.

【0050】

In the configuration example of FIG. 10, the reaction chamber is a horizontal reaction tube, but the basic configuration is the same as that of the configuration example of FIG. 4, and the same effect as that of the configuration example of FIG. 4 can be obtained.

【0051】

That is, in the apparatus of FIG. 10, a substrate for growing the semiconductor light emitting element and a susceptor for holding the substrate are attached to the object to be heated. Here, the susceptor is made of, for example, carbon, and a recess for holding the substrate is provided on the susceptor. In addition, the susceptor is shaped so as to cover the body to be heated so that it can be attached and detached. Further, the body to be heated is also made of carbon, and the susceptor and the body to be heated can be heated by, for example, induction heating.

【0052】

In such a configuration, the raw material gas introduced from the raw material gas supply port causes a chemical reaction on the surface of the substrate on the heated susceptor to grow the semiconductor layer. As shown in FIG. 11, this susceptor can be attached to and detached from the body to be heated, and after being pulled out to the second chamber for transportation, the susceptor and the substrate mounted on the susceptor can be transported to the sample chamber. The sample chamber itself can be evacuated independently or purged with hydrogen, nitrogen, etc. For example, the susceptor and the substrate can be transported to the reaction chamber in a hydrogen atmosphere. A plurality of susceptors are prepared in the sample chamber, and the substrate on the susceptors can be moved onto any susceptor by a vacuum chuck or the like.

【0053】

In the above apparatus, the semiconductor light emitting device having the configuration shown in FIG. 2 can be grown in the same process as described above.

【0054】

In this way, the horizontal reaction tube is completely the same as the vertical reaction tube, and by using the step of exchanging the susceptor, the susceptor without adsorption is not the susceptor on which the substance containing Al is adsorbed when the active layer is grown. Can be used, and a substance containing Al can be prevented from coming into contact with the nitrogen compound raw material or impurities contained in the nitrogen compound raw material and being taken into the active layer, so that a low threshold semiconductor light emitting device can be grown. be able to.

【0055】

Second embodiment As described in the first embodiment, when a semiconductor light emitting device using a nitrogen-containing active layer is grown, if a substance containing Al is adsorbed on a susceptor adjacent to the substrate before the active layer grows, This reacts and is taken up when the active layer containing nitrogen grows, and there is an extremely high risk of causing a decrease in luminous efficiency. In order to reduce this risk, in the second embodiment of the present invention, a removable cover is provided as a means for preventing the substance containing Al from being adsorbed on the susceptor.

【0056】

FIG. 7 is a diagram showing a configuration example of a semiconductor light emitting device manufacturing apparatus according to a second embodiment of the present invention. Note that FIG. 7 is a schematic view of the vertical cross section of the reaction chamber of the MOCVD apparatus as viewed from the side. In the configuration example of FIG. 7, the reaction chamber is a vertical reaction tube, and a substrate for growing a semiconductor light emitting element and a susceptor for holding the substrate are provided inside.

【0057】

In such a configuration, the raw material gas introduced from the raw material gas supply port causes the semiconductor layer to grow by a chemical reaction on the substrate surface on the susceptor heated to a high temperature by resistance heating built in the stage under the susceptor, for example. It has become.

【0058】

By the way, in this second embodiment, the susceptor is covered with a removable cover except for the portion on which the substrate is mounted (see FIG. 8). This cover is removable in the reaction chamber so as not to impair the atmosphere, and can be taken out of the reaction chamber. In this case, problems such as contamination and oxidation of the substrate do not occur before and after the cover is attached and detached. Further, the cover should have a structure that covers almost the entire surface of the susceptor except for the exposed portion of the substrate. In this case, when the layer containing Al grows, if it grows in a state of being covered with this cover, the substance containing Al is hardly adsorbed on the susceptor.

【0059】

As described above, the semiconductor light emitting device having high luminous efficiency can be manufactured by the semiconductor light emitting device manufacturing method or the semiconductor light emitting device manufacturing apparatus of each of the above-described embodiments.

【0060】

Further, in the present invention, the surface emitting semiconductor laser can be manufactured by the semiconductor light emitting device manufacturing method or the semiconductor light emitting device manufacturing apparatus of each of the above-described embodiments. FIG. 9 is a diagram showing an example of a surface emitting semiconductor laser manufactured by the method for manufacturing a semiconductor light emitting device of the present invention or the apparatus for manufacturing a semiconductor light emitting device. Referring to FIG. 9, this surface emitting semiconductor laser has an n-type semiconductor multilayer film reflector 52, a GaAs lower spacer layer 53, a GaInNAs / GaAs multiple quantum well active layer 54, and a GaAs upper spacer on an n-type GaAs substrate 51. The layer 55, the AlAs layer 56, and the p-type semiconductor multilayer film reflector 57 are sequentially formed.

【0061】

Here, the n-type semiconductor multilayer film reflector 52 includes an n-type GaAs high refractive index layer and an n-type Al._0.8Ga_0.2It is composed of a distributed Bragg reflector in which As low refractive index layers are alternately laminated. Similarly, the p-type semiconductor multilayer reflector 57 also has a p-type GaAs high refractive index layer and a p-type Al._0.8Ga_0.2It is composed of a distributed Bragg reflector in which As low refractive index layers are alternately laminated.

【0062】

The GaInNAs / GaAs multiple quantum well active layer 54 has a bandgap wavelength of 1.3 μm. The GaAs lower spacer layer 53 to the GaAs upper spacer layer 55 form a λ resonator.

【0063】

Then, the laminated structure is etched into a cylindrical shape until it reaches the n-type semiconductor multilayer film reflector 52, and a mesa structure is formed. The mesa size is 30 μmφ. Then, the AlAs layer 56 is selectively oxidized from the side surface exposed by etching to form AlO._xBy forming the insulating region, a current constriction structure is formed. In this case, the current is AlO_xThe insulating region concentrates the oxide opening region of about 5 μmφ and is injected into the active layer 54.

【0064】

A ring-shaped p-side electrode 58 is formed on the front surface of the p-type semiconductor multilayer film reflector 57, and an n-side electrode 59 is formed on the back surface of the n-type GaAs substrate 51.

【0065】

In the surface emitting semiconductor laser having such a configuration, the light emitted by the GaInNAs / GaAs multiple quantum well active layer 54 is reflected and amplified by the upper and lower semiconductor multilayer film reflectors 52 and 57, and the laser light in the 1.3 μm band is amplified. Radiates perpendicular to the substrate 51.

【0066】

In the surface emitting semiconductor laser having such a configuration, the AlGaAs / GaAs laminated type is the easiest to manufacture a high-performance reflecting mirror as the semiconductor multilayer film reflecting mirror 52 on the GaAs substrate 51, and the electrical characteristics are also good. Therefore, it is easy to use. In fact, the 0.85 μm band and 0.98 μm band VCSELs are actually manufactured and sold using an AlGaAs / GaAs laminated semiconductor multilayer film reflector, and in a surface emitting semiconductor laser on a GaAs substrate, this AlGaAs / GaAs laminate is used. A type of semiconductor multilayer film reflector is indispensable. However, in the past, when a surface-emitting semiconductor laser using an active layer containing nitrogen was grown by MOCVD, when trying to make a reflector 52 with an AlGaAs / GaAs laminated type, the quality of the active layer 54 deteriorated due to the reasons described above. However, it was not possible to obtain an element with a low threshold current.

【0067】

The process of growing the surface-emitting semiconductor laser shown in FIG. 9 was as follows. That is, first, the n-type semiconductor multilayer film reflector 52 is grown. While the n-type semiconductor multilayer film reflector 52 is grown, the reaction is carried out so as to cover the susceptor with the cover. Then, the adsorption of the substance containing Al is almost nonexistent to the susceptor, and the adsorption to the cover is almost nonexistent.

【0068】

Next, the lower spacer layer 53 and the active layer 54 are grown. At this time, I decided to remove the cover. The removed cover is moved out of the reaction chamber system. By removing the cover, the substance containing Al is removed from the reaction chamber system together with the cover, so that it can be prevented from coming into contact with the nitrogen compound raw material or impurities contained in the nitrogen compound raw material and being taken into the substrate. .. In the apparatus of the second embodiment, since the cover can be removed and the device can be moved out of the reaction chamber system without damaging the atmosphere, the step of removing the cover ends the growth of the layer containing Al. After that, it may be carried out anywhere as long as it is until the growth of the active layer 54 starts. For example, a step of removing the cover can be performed between the growth of the lower spacer layer 53 and the n-type semiconductor multilayer reflector 52.

【0069】

After that, the upper spacer layer 55 and the p-type semiconductor multilayer film reflector 57 are grown, and the crystal growth is completed. When growing the p-type semiconductor multilayer film reflector 57, the cover may be reattached. By reattaching it, it is possible to prevent the adsorption of substances containing Al on the susceptor during the growth of the p-type semiconductor multilayer reflector 57. In particular, when the semiconductor light emitting device is continuously grown, the substance containing Al adsorbed on the susceptor when the p-type semiconductor multilayer film reflector 57 is grown is desorbed from the susceptor during the next growth and becomes active. Since there is a great concern that the layer 54 may be adversely affected, it is preferable to attach a cover when growing the p-type semiconductor multilayer film reflector 57. As described above, by using the manufacturing apparatus and manufacturing method according to the present invention, a low-threshold surface-emitting semiconductor laser composed of an active layer 54 such as GaInNAs can be used even when the AlGaAs / GaAs laminated semiconductor multilayer film reflector 52 is used. Can grow.

【0070】

As described above, in the method for manufacturing a semiconductor light emitting device and the manufacturing apparatus for a semiconductor light emitting device according to the second embodiment of the present invention, a semiconductor layer containing Al is provided between a substrate and an active layer containing nitrogen, and the nitrogen is used. When the active layer containing the active layer and the semiconductor layer containing Al are grown using the nitrogen compound raw material and the organic metal Al raw material, respectively, the susceptor holding the substrate is attached and detached so as to cover a portion other than the portion directly holding the substrate. It has a possible cover, and has a mechanism for attaching a cover when growing the semiconductor layer containing Al and removing the cover when growing the active layer containing nitrogen.

【0071】

Here, the removable cover has a mechanism that can be attached and detached in a state where the susceptor is loaded in the reaction chamber.

【0072】

FIG. 12 is a diagram showing a configuration example of the semiconductor light emitting device manufacturing apparatus of the present invention. Note that FIG. 12 is a schematic view of the vertical cross section of the reaction chamber of the MOCVD apparatus as viewed from the side. In the example of FIG. 12, the reaction chamber is a horizontal reaction tube.

【0073】

In the apparatus of FIG. 12, a substrate for growing the semiconductor light emitting element and a susceptor for mounting the substrate are held in the growth chamber. The susceptor is made of, for example, carbon, and a recess for holding the substrate is provided on the susceptor.

【0074】

The cover is made of, for example, quartz, and is designed to cover the susceptor so that it can be attached and detached (see FIG. 13).

【0075】

The susceptor can be heated by induction heating, and the raw material gas introduced from the raw material gas supply port causes a chemical reaction on the surface of the substrate on the heated susceptor to grow the semiconductor layer. The susceptor is attached to a support rod so that it can be moved in and out between the reaction chamber and the second transport chamber. In the second transport chamber, the susceptor can be removed from the support rod, and the removed susceptor can be moved between the sample chamber and the substrate and cover. Each room can be shut off by, for example, a gate valve, and the inside can be adjusted to an arbitrary atmosphere. In this embodiment, the cover is simply put on the susceptor, and the cover is first transferred from the reaction chamber to the second transport chamber, and then the susceptor and the substrate are removed from the support rod and transported to the sample chamber. Then, in the sample chamber, it can be removed with the cover attachment / detachment lever as shown in FIG.

【0076】

In this apparatus, a semiconductor light emitting device as shown in FIG. 2 was grown by the following process.

【0077】

That is, the first semiconductor layer 202 containing Al is grown on the substrate 201. After completing the step of growing the semiconductor layer 202 (for example, AlGaAs) containing Al, the intermediate layer 203 (for example, GaAs) is grown halfway. Next, once the growth is stopped, the substrate and the susceptor are transported to the sample chamber, and the cover is removed. After that, it is transported to the reaction chamber again, and the remaining lower intermediate layer 203, active layer 204, and upper intermediate layer 203 are grown halfway. After that, the growth is stopped again, the sample chamber is transported, the cover is attached, and then the sample chamber is transported again to grow the remaining upper intermediate layer 203 and the second semiconductor layer 205 containing Al.

【0078】

Since the cover is attached / detached using the cover attachment / detachment lever without opening the sample chamber to the atmosphere, it is possible to eliminate the influence of contamination or oxidation of the substrate due to the opening to the atmosphere.

【0079】

By the above steps, it is possible to prevent the substance containing Al from coming into contact with the nitrogen compound raw material or the impurities contained in the nitrogen compound raw material and being taken into the active layer, so that a low threshold semiconductor light emitting device is grown. We were able to.

【0080】

Further, in this embodiment, the step of attaching / detaching the cover can be carried out by deforming even when there is no lever for attaching / detaching the cover, for example. At this time, the step of attaching and detaching the cover can be carried out by opening the sample chamber to the atmosphere and manually performing the process. However, since the substrate is open to the atmosphere, it may be affected by oxidation. In this example, the growth is interrupted in the middle of the intermediate layer GaAs. Since GaAs is less likely to be oxidized than AlGaAs, if GaAs is used as the outermost surface instead of AlGaAs, the effect of oxidation due to opening to the atmosphere for a short time can be reduced. As a result, the influence of opening to the atmosphere can be minimized.

【0081】

Although manually attaching and detaching the cover in this way is affected by the opening to the atmosphere, it is not necessary to prepare a lever for attaching and detaching the cover, so that the configuration of the device is extremely simple. As a result, it can be compared and easily carried out in the existing general MOCVD equipment. That is, if the layout of the reaction chamber allows, this embodiment can be carried out simply by making a cover that can be installed and transported. In general, MOCVD equipment is extremely expensive and cannot be easily modified beyond a certain level. However, in this embodiment, the present invention can be carried out at low cost without performing a large-scale modification. In addition, since the lever for attaching / detaching the cover only needs to be attached to the sample chamber, it is not difficult to carry out because a large-scale modification is not required even when this mechanism is incorporated.

【0082】

Further, in the present invention, an optical transmission module using a surface emitting semiconductor laser produced by the semiconductor light emitting device manufacturing method of each of the above-described embodiments or a semiconductor light emitting device manufacturing apparatus, an optical transmission / reception module, or light. A communication system can be constructed.

【0083】

FIG. 15 is a diagram showing an example of an optical transmission module according to the present invention. Further, FIG. 16 is a diagram showing an example of an optical transmission / reception module according to the present invention .

【0084】

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 FIGS. 15 and 16, the surface-emitting semiconductor laser device for transmission is used. An optical transmission module or an optical transmission / reception module that combines a receiving photodiode and an optical fiber can be obtained.

【0085】

For example, a surface-emitting laser using GaInNAs is an element that can obtain oscillation in the 1.2-1.3 μm band, and as a light source for communication because there is little loss to quartz-based optical fibers at these wavelengths. It is said to be suitable. Furthermore, the cost of the fiber is low when a fluoridated POF (plastic fiber), which has low loss in a long wavelength band such as 1.3 μm, and a surface emitting laser using GaInNAs as the active layer are combined, and the diameter of the fiber. Since the size is large, coupling with the fiber is easy, and the mounting cost can be reduced, an extremely low cost module can be realized. In addition, GaInNAs do not require a strong cooling configuration due to their excellent temperature characteristics. Therefore, the cost for cooling can be reduced, and an inexpensive optical communication module can be obtained.

【0086】

According to the present invention, since an active layer containing high-quality nitrogen can be grown, it becomes easier to manufacture a surface-emitting semiconductor laser device as shown in FIG. 9, and high performance is achieved. A long-wavelength band surface emitting semiconductor laser device for communication can be realized, and by using these devices, an optical communication system such as a low-cost optical fiber communication system and an optical interconnection system can be realized.

【0087】

[Effect of the invention]

As described above, according to the inventions of claims 1 and 2, a semiconductor layer containing Al is provided between the substrate and the active layer containing nitrogen, and the active layer containing nitrogen and the Al are separated from each other. When growing a semiconductor layer containing nitrogen using a nitrogen compound raw material and an organic metal Al raw material, respectively, when growing a susceptor that holds a substrate when growing the semiconductor layer containing Al, and when growing an active layer containing nitrogen. By making the susceptor that holds the substrate different from the susceptor that holds the substrate, the substance containing Al adsorbed on the susceptor when growing the semiconductor layer containing Al is a nitrogen compound raw material or a nitrogen compound when growing the active layer containing nitrogen. It is possible to prevent the semiconductor from being taken into the substrate by coming into contact with impurities contained in the raw material, and it is possible to grow a semiconductor light emitting element having a low threshold value.

【0088】

Further, according to the invention of claim 3, while the semiconductor layer containing Al is being grown, the susceptor for growing the active layer containing nitrogen is kept on standby in a room separate from the growth chamber, and the semiconductor layer containing Al is kept on standby. Since the semiconductor has a structure in which the susceptor for growing the active layer containing nitrogen and the susceptor for growing the semiconductor layer containing Al can be exchanged without exposing the substrate to the atmosphere after the growth of the semiconductor is completed. It is possible to provide an apparatus capable of replacing the susceptor without exposing the substrate to the atmosphere during the growth of the light emitting element, and reducing the risk of contamination and oxidation of the substrate while having the effect of claim 2.

【0089】

Further, according to the invention of claim 4, a semiconductor layer containing Al is provided between the substrate and the active layer containing nitrogen, and the active layer containing pre-nitrogen and the semiconductor layer containing Al are each used as a nitrogen compound raw material. In the method for manufacturing a semiconductor light emitting element that has been grown using the organic metal Al raw material, the susceptor that holds the substrate has a removable cover that covers a portion other than the portion that directly holds the substrate, and contains Al. By attaching a cover when growing the semiconductor layer and removing the cover when growing the active layer containing nitrogen, the substance containing Al adsorbed on the cover when growing the semiconductor layer containing Al releases nitrogen. When the active layer containing the active layer is grown, it can be prevented from coming into contact with the nitrogen compound raw material or impurities contained in the nitrogen compound raw material and being taken into the substrate, and a low threshold semiconductor light emitting element can be grown.

【0090】

Further, according to the invention of claim 5, a semiconductor layer containing Al is provided between the substrate and the active layer containing nitrogen, and the active layer containing nitrogen and the semiconductor layer containing Al are respectively used as a nitrogen compound raw material. In a semiconductor light emitting element manufacturing apparatus for growing a semiconductor light emitting element using an organic metal Al raw material, the susceptor that holds the substrate has a removable cover that covers a portion other than the portion that directly holds the substrate, and Al. By having a mechanism to attach a cover when growing a semiconductor layer containing Al and to remove the cover when growing an active layer containing nitrogen, Al adsorbed on the cover when growing a semiconductor layer containing Al When the contained substance grows the active layer containing nitrogen, it can be prevented from coming into contact with the nitrogen compound raw material or the impurities contained in the nitrogen compound raw material and being taken into the substrate, and a low threshold semiconductor light emitting element is grown. be able to.

【0091】

Further, according to the invention of claim 6, since the removable cover has a mechanism that can be detached while the susceptor is loaded in the reaction chamber, the substrate is exposed to the atmosphere during the growth of the semiconductor light emitting device. It is possible to provide an apparatus capable of attaching and detaching a cover without exposing it to the inside and reducing the risk of contamination and oxidation of a substrate while having the effect of claim 5.

【0092】

Further, according to the invention according to claim 7, the method for manufacturing a semiconductor light emitting device according to claim 1 or 4, or the semiconductor according to claim 2 or 3, or 5 or 6. Since it is a surface-emitting semiconductor laser device manufactured by a device for manufacturing a light-emitting device, even if a semiconductor multilayer film reflector with an AlGaAs / GaAs laminate is used, it is low, which is composed of an active layer containing N such as GaInNAs. A threshold surface-emitting semiconductor laser device can be grown (provided).

【0093】

Further, according to the invention of claim 8, since the optical transmission module is characterized in that the surface emitting semiconductor laser device of claim 7 is used, a high quality active layer containing N such as GaInNAs is used. However, it is possible to provide a low-cost, compact optical transmission module that uses a surface-emitting semiconductor laser device that uses a material that matches well with an optical fiber as a light source.

【0094】

Further, according to the invention of claim 9, since the optical transmission / reception module is characterized in that the surface emitting semiconductor laser device of claim 7 is used, a high-quality active layer containing N such as GaInNAs is used. However, it is possible to provide a low-cost, compact optical communication module that uses a surface-emitting semiconductor laser device that uses a material that matches well with an optical fiber as a light source.

【0095】

Further, according to the invention of claim 10, since the optical communication system is characterized in that the surface emitting semiconductor laser device of claim 7 is used, a high-quality active layer containing N such as GaInNAs is used. However, it is possible to provide a low-cost, compact optical communication system that uses a surface-emitting semiconductor laser device that uses a material that matches well with an optical fiber as a light source.

[Simple explanation of drawings]

[Figure 1]

It is a figure which shows the room temperature photoluminescence spectrum of the GaInNAs / GaAs2 weight well structure composed of a GaInNAs quantum well layer and a GaAs barrier layer produced by the MOCVD apparatus by the inventor of the present application.

[Figure 2]

It is a figure which shows an example of the semiconductor light emitting element which provided the semiconductor layer containing Al between a substrate and a semiconductor layer containing nitrogen.

[Fig. 3]

As an example of the semiconductor light emitting device shown in FIG. 2, a semiconductor light emitting device having a first semiconductor layer, a second semiconductor layer of AlGaAs, an intermediate layer of GaAs, and an active layer containing nitrogen as a GaInNAs / GaAs2 weight element well structure. It is a figure which shows the distribution in the depth direction of the nitrogen (N) concentration and the oxygen (O) concentration when it was formed by using one epitaxial growth apparatus (MOCVD).

[Fig. 4]

It is a figure which shows the structural example of the manufacturing apparatus of the semiconductor light emitting element of 1st Embodiment of this invention.

[Fig. 5]

It is a figure for demonstrating transfer | transport of a susceptor and a substrate.

[Fig. 6]

It is a figure for demonstrating the transfer mechanism of a substrate.

[Fig. 7]

It is a figure which shows the structural example of the manufacturing apparatus of the semiconductor light emitting element of the 2nd Embodiment of this invention.

[Fig. 8]

It is a figure which shows the susceptor which is covered with a removable cover.

[Fig. 9]

It is a figure which shows an example of the surface light emitting type semiconductor laser manufactured by the manufacturing method of the semiconductor light emitting element of this invention, and the manufacturing apparatus of a semiconductor light emitting element.

[Fig. 10]

It is a figure which shows the modification of the manufacturing apparatus of the semiconductor light emitting element of 1st Embodiment of this invention.

[Fig. 11]

It is a figure for demonstrating the transport of a susceptor.

[Fig. 12]

It is a figure which shows the structural example of the manufacturing apparatus of the semiconductor light emitting element of this invention.

[Fig. 13]

It is a figure which shows the removable cover on the susceptor.

[Fig. 14]

It is a figure for demonstrating the removal of a cover by a lever for attaching and detaching a cover.

[Fig. 15]

It is a figure which shows an example of the optical transmission module which concerns on this invention.

[Fig. 16]

It is a figure which shows an example of the optical transmission module which concerns on this invention.

[Explanation of symbols]

51 n type GaAs substrate 52 n-type semiconductor multilayer mirror 53 GaAs lower spacer layer 54 GaInNAs / GaAs multiple quantum well active layer 55 GaAs upper spacer layer 56 AlAs layer 57 p-type semiconductor multilayer mirror 58 p side electrode 59 n side electrode 201 board 201 First semiconductor layer 203 Intermediate layer 204 Active layer 205 Second semiconductor layer