Method for manufacturing semiconductor light emitting element, surface emitting semiconductor laser element, optical transmission module, optical transmission/ reception 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, a surface emitting semiconductor laser 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. Therefore not only the trunk line, metro network, more general household and office optical fiber also to the transmission path closer to the user, such as a subscriber or LAN went (Local Area Network), and more wire within or between devices each device Is being introduced. 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 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 provides a method for manufacturing 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.

【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 element to be grown using a nitrogen compound raw material and an organic metal Al raw material, respectively, the temperature of the growth chamber wall after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. Was kept at a temperature higher than the temperature of the growth chamber wall when growing the nitrogen-containing active layer and purged, and Al raw material, Al reaction product, Al compound, or Al was transferred from the growth chamber wall. It is characterized by removing it.

【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 the method for manufacturing a semiconductor light emitting element to be grown using a metal Al raw material, after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown, the temperature of the growth chamber wall is changed to the activity containing nitrogen. Keeping the temperature higher than the temperature of the growth chamber wall when the layer is grown, and purging by flowing side flow gas along the growth chamber wall, Al raw material, Al reaction product, or Al compound, Alternatively, it is characterized by removing Al from the growth chamber wall.

【0014】

Further, in the invention according to claim 3, 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 element to be grown using a metal Al raw material, the temperature of the susceptor holding the substrate is set to the temperature of the nitrogen after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. It is characterized in that the active layer containing the active layer is kept at a temperature higher than the temperature of the susceptor when it is grown and purged to remove the Al raw material, the Al reaction product, the Al compound, or Al from the susceptor.

【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 element to be grown using a metal Al raw material, the temperature of the susceptor holding the substrate is set to the temperature of the nitrogen after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. The temperature of the active layer containing the active layer is kept higher than the temperature of the susceptor when growing, and the side flow gas is flowed along the susceptor to perform purging, and the Al raw material, the Al reaction product, the Al compound, or the Al compound, or It is characterized by removing Al from the susceptor.

【0016】

The invention according to claim 5 is the method for manufacturing a semiconductor light emitting device according to any one of claims 1 or 2, and the semiconductor light emitting device according to any one of claims 3 or 4. It is characterized by removing an Al raw material, an Al reaction product, an Al compound, or Al from a growth chamber wall and a susceptor in combination with a method for producing a device.

【0017】

The invention according to claim 6 is a surface emitting semiconductor laser device, characterized in that it is manufactured by the method for manufacturing a semiconductor light emitting device according to any one of claims 1 to 5.

【0018】

The invention according to claim 7 is an optical transmission module characterized in that the surface emitting semiconductor laser device according to claim 6 is used.

【0019】

The invention according to claim 8 is an optical transmission / reception module characterized in that the surface emitting semiconductor laser device according to claim 6 is used.

【0020】

The invention according to claim 9 is an optical communication system characterized in that the surface emitting semiconductor laser device according to claim 6 is used.

【0021】

BEST MODE FOR CARRYING OUT THE INVENTION

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

【0022】

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 in sequence.

【0023】

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

【0024】

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.

【0025】

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.

【0026】

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.

【0027】

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.

【0028】

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.

【0029】

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.

【0030】

[table 1]

<img file="JP2003174238A_D0001.tif" />【0031】

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.

【0032】

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.

【0033】

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.

【0034】

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.

【0035】

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 may be combined and incorporated into the active layer. It was found that this is a factor in the manufacturing process that lowers the light emission 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.

【0036】

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.

【0037】

First Embodiment FIGS. 4 (a) and 4 (b) are diagrams showing a configuration example of a semiconductor light emitting device manufacturing apparatus according to the first embodiment of the present invention. Note that FIGS. 4 (a) and 4 (b) are views showing a vertical cross section of the reaction chamber (growth chamber) of the MOCVD apparatus.

【0038】

In the configuration examples of FIGS. 4A and 4B, the reaction chamber (growth chamber) 1 is a horizontal reaction tube, and has a raw material gas supply port 4 and an exhaust port 6. Further, inside the reaction chamber (growth chamber) 1, a substrate 2 for growing the semiconductor light emitting element and a susceptor 3 for holding the substrate 2 are provided.

【0039】

Further, in the configuration examples of FIGS. 4A and 4B, the reaction chamber 1 is provided with a heater 7 for heating the wall surface of the reaction chamber 1, and the heater 7 provides the temperature of the wall surface of the reaction chamber 1. Can be changed arbitrarily.

【0040】

In the semiconductor light emitting device manufacturing apparatus of the first embodiment, the raw material gas introduced from the raw material gas supply port 4 is a semiconductor by a chemical reaction on the surface of the substrate 2 on the susceptor 3 held at a high temperature by, for example, resistance heating or the like. Grow layers.

【0041】

By the way, in this first embodiment, the reaction chamber 1 is provided with a heater 7 for heating the wall surface, and the heater 7 makes it possible to arbitrarily change the temperature of the wall surface of the reaction chamber 1. .. That is, by raising the temperature of the wall surface of the reaction chamber 1 by the heater 7, it is possible to promote the desorption of the raw material gas adsorbed on the inner wall of the reaction chamber 1 and the product due to the chemical reaction.

【0042】

As described above, in the first embodiment of the present invention, 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 nitrogen. In the method for producing a semiconductor light emitting element to be grown using a compound raw material and an organic metal Al raw material, a growth chamber (reaction chamber 1) is used after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. The temperature of the inner wall is kept higher than the temperature of the inner wall of the growth chamber (reaction chamber 1) when growing the active layer containing nitrogen, and purging is performed. , Al is removed from the inner wall of the growth chamber (reaction chamber 1).

【0043】

As described above, when 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 chamber reduces the luminous efficiency. Therefore, removing this is effective for improving the luminous efficiency.

【0044】

In this first embodiment, when the semiconductor layer containing Al is grown, the Al raw material gas adsorbed and remained on the inner wall of the growth chamber (reaction chamber 1) and the reaction product containing Al are grown, and the active layer containing nitrogen is grown. By heating the wall surface of the growth chamber (reaction chamber 1) for a certain period of time and purging the inside of the reaction chamber 1 with a gas such as hydrogen, the inside wall of the reaction chamber 1 is desorbed from the nitrogen compound raw material or the nitrogen compound raw material. It is designed to prevent impurities such as water contained therein and substances containing residual Al from binding and being incorporated into the active layer.

【0045】

In the first embodiment, purging is performed during the growth of the semiconductor layer containing Al and the intermediate layer. At this time, by raising the temperature for heating the wall surface (inner wall) of the reaction chamber 1 higher than the temperature of the inner wall of the reaction chamber 1 when growing the active layer, it is easier to separate from the wall surface than when growing the active layer. Purging is performed in the state, and when the active layer is actually grown, the substance containing Al can be prevented from desorbing from the wall surface, and as a result, the substance containing Al is contained in the nitrogen compound raw material or the nitrogen compound raw material. It is possible to prevent the semiconductor light emitting device from coming into contact with the impurities and being incorporated into the substrate, and to grow a semiconductor light emitting device having a low temperature.

【0046】

The above step can effectively purge in a shorter time than when a purging step for simply removing a substance containing Al is provided.

【0047】

Second embodiment FIG. 5 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. 5 is a diagram showing a vertical cross section of the reaction chamber (growth chamber) of the MOCVD apparatus. In FIG. 5, the same parts as those in FIG. 4 are designated by the same reference numerals.

【0048】

In the configuration example of FIG. 5, the reaction chamber (growth chamber) 1 is a horizontal reaction tube, and has a raw material gas supply port 4, a side flow gas supply port 5, and an exhaust port 6. Further, inside the reaction chamber (growth chamber) 1, a substrate 2 for growing the semiconductor light emitting element and a susceptor 3 for holding the substrate 2 are provided.

【0049】

Further, the reaction chamber 1 is provided with a heater 7 for heating the wall surface, and the temperature of the wall surface of the reaction chamber 1 can be arbitrarily changed by the heater 7.

【0050】

The feature of the semiconductor light emitting device manufacturing apparatus of the second embodiment is that when the semiconductor layer containing Al is grown and / or nitrogen is added, as compared with the semiconductor light emitting device manufacturing apparatus of the first embodiment. It has a structure in which a side flow gas flows along the inner wall of the reaction chamber (growth chamber) 1 when the active layer containing the active layer is grown.

【0051】

In the semiconductor light emitting device manufacturing apparatus having such a configuration, the raw material gas introduced from the raw material gas supply port 4 is a semiconductor layer by a chemical reaction on the surface of the substrate 2 on the susceptor 3 held at a high temperature by, for example, resistance heating or the like. To grow.

【0052】

On the other hand, a side flow gas containing no raw material gas is introduced from the side flow gas supply port 5 so that the side flow gas flows along the inner wall of the reaction chamber 1. Further, by raising the temperature of the wall surface of the reaction chamber 1 by the heater 7, it is possible to promote the desorption of the raw material gas adsorbed on the inner wall of the reaction chamber 1 and the product due to the chemical reaction. Further, in the step of heating the wall surface to perform purging, it is possible to promote the desorption of the raw material gas adsorbed on the inner wall and the product due to the chemical reaction more quickly and effectively by flowing the side flow gas. .. 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 incorporated into the substrate, and it is possible to grow a semiconductor light emitting device having a low threshold value.

【0053】

As described above, in the second embodiment of the present invention, 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 nitrogen. In the method for manufacturing a semiconductor light emitting element to be grown using a compound raw material and an organic metal Al raw material, the temperature of the growth chamber wall is set after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. The temperature of the active layer containing nitrogen is kept higher than the temperature of the growth chamber wall when growing, and the side flow gas is flowed along the growth chamber wall to perform purging. , Al compound, or Al is removed from the growth chamber wall.

【0054】

Third embodiment FIG. 6 is a diagram showing a configuration example of a semiconductor light emitting device manufacturing apparatus according to a third embodiment of the present invention. Note that FIG. 6 is a diagram showing a cross section of the reaction chamber of the MOCVD apparatus.

【0055】

In the configuration example of FIG. 6, the reaction chamber 1 is a horizontal reaction tube, and inside the reaction chamber 1, a substrate 2 for growing a semiconductor light emitting element and a susceptor 3 for holding the substrate 2 are provided. It is provided.

【0056】

In such a configuration, the raw material gas introduced from the raw material gas supply port 4 grows a semiconductor layer by a chemical reaction on the surface of the substrate 2 on the susceptor 3 held at a high temperature by, for example, resistance heating. When the semiconductor layer containing Al is grown, the reaction product containing the Al raw material gas and Al adsorbed and remaining on the susceptor 3 is heated for a certain period of time before the active layer containing nitrogen is grown, and the reaction chamber 1 By purging the inside with a gas such as hydrogen, it is desorbed from the susceptor 3, and 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. Can be prevented. At this time, by raising the temperature at which the susceptor 3 is heated higher than the temperature of the susceptor 3 when the active layer is grown, purging is performed in a state where it is easier to separate from the susceptor 3 than when the active layer is grown. When the active layer is actually grown, the substance containing Al can be prevented from desorbing from the susceptor 3. 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 incorporated into the substrate, and it is possible to grow a semiconductor light emitting device having a low threshold value.

【0057】

As described above, in the third embodiment of the present invention, 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 nitrogen. In the method for manufacturing a semiconductor light emitting element to be grown using a compound raw material and an organic metal Al raw material, the temperature of the susceptor holding the substrate after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. Is kept at a temperature higher than the temperature of the susceptor when the active layer containing nitrogen is grown and purged to remove the Al raw material, the Al reaction product, the Al compound, or Al from the susceptor.

【0058】

Fourth Embodiment FIG. 7 is a diagram showing a configuration example of a semiconductor light emitting device manufacturing apparatus according to a fourth embodiment of the present invention. Note that FIG. 7 is a diagram showing a cross section of the reaction chamber of the MOCVD apparatus.

【0059】

In the configuration example of FIG. 7, the reaction chamber (growth chamber) 1 is a horizontal reaction tube, and has a raw material gas supply port 4, a side flow gas supply port 5, and an exhaust port 6. Further, inside the reaction chamber (growth chamber) 1, a substrate 2 for growing the semiconductor light emitting element and a susceptor 3 for holding the substrate 2 are provided.

【0060】

In such a configuration, the raw material gas introduced from the raw material gas supply port 4 grows a semiconductor layer by a chemical reaction on the surface of the substrate 2 on the susceptor 3 held at a high temperature by, for example, resistance heating.

【0061】

On the other hand, a side flow gas containing no raw material gas is introduced from the side flow gas supply port 5, and an outlet is provided so as to flow along the side surface of the susceptor 3.

【0062】

In this fourth embodiment, the Al raw material gas and the reaction product containing Al adsorbed and remained on the susceptor 3 when the semiconductor layer containing Al was grown, and the susceptor 3 was applied before the active layer containing nitrogen was grown. Nitrogen compound raw material or nitrogen compound by heating for a certain period of time and promoting the desorption of raw material gas and substances generated by chemical reaction from susceptor 3 and the like by the side flow gas flowing to the side surface of the susceptor 3 and purging. It is possible to prevent impurities such as water contained in the raw material and substances containing residual Al from binding and being incorporated into the active layer. At this time, by raising the temperature at which the susceptor 3 is heated higher than the temperature of the susceptor when the active layer is grown, purging is performed in a state where it is easier to separate from the susceptor 3 than when the active layer is grown. It is possible to prevent the substance containing Al from desorbing from the susceptor 3 when the active layer is grown. 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 incorporated into the substrate, and it is possible to grow a semiconductor light emitting device having a low threshold value.

【0063】

As described above, in the fourth embodiment of the present invention, 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 nitrogen. In the method for manufacturing a semiconductor light emitting element to be grown using a compound raw material and an organic metal Al raw material, the temperature of the susceptor holding the substrate after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. Is kept at a temperature higher than the temperature of the susceptor when the active layer containing nitrogen is grown, and a side flow gas is flowed along the susceptor to perform purging. Remove the compound or Al from the susceptor.

【0064】

FIG. 8 is a diagram showing a modified example of the semiconductor light emitting device manufacturing apparatus of FIG. Note that FIG. 8 is a schematic view of the vertical cross section of the reaction chamber of the MOCVD apparatus as viewed from the side. Further, in FIG. 8, the same reference numerals are given to the parts corresponding to those in FIG. 7.

【0065】

In the configuration example of FIG. 8, the reaction chamber 1 is a vertical reaction tube, and inside the reaction chamber 1, a substrate 2 for growing a semiconductor light emitting element and a susceptor 3 for holding the substrate 2 are provided. Is provided.

【0066】

In the semiconductor light emitting device manufacturing apparatus having such a configuration, the raw material gas introduced from the raw material gas supply port 4 is a semiconductor layer by a chemical reaction on the surface of the substrate 2 on the susceptor 3 held at a high temperature by, for example, resistance heating or the like. Is designed to grow. Further, the reaction chamber 1 is provided with a heater for heating the wall surface, which makes it possible to arbitrarily change the temperature of the wall surface.

【0067】

As described above, the operation of the configuration example of FIG. 8 is basically the same as that of the configuration example of FIG. 7, and the same effect as that of the configuration example of FIG. 7 can be obtained. A MOCVD apparatus using a vertical reaction tube as shown in the configuration example of FIG. 8 is relatively easy to obtain film uniformity, so that a surface emitting semiconductor laser or the like that requires film thickness uniformity is used. Often used during mass production.

【0068】

Fifth embodiment FIG. 9 is a diagram showing a configuration example of a semiconductor light emitting device manufacturing apparatus according to a fifth embodiment of the present invention. Note that FIG. 9 is a schematic view showing a cross section of the reaction chamber of the MOCVD apparatus.

【0069】

In the configuration example of FIG. 9, the reaction chamber (growth chamber) 1 is a horizontal reaction tube, and has a raw material gas supply port 4, a side flow gas supply port 5, and an exhaust port 6. Further, inside the reaction chamber (growth chamber) 1, a substrate 2 for growing the semiconductor light emitting element and a susceptor 3 for holding the substrate 2 are provided.

【0070】

In such a configuration, the raw material gas introduced from the raw material gas supply port 4 grows a semiconductor layer by a chemical reaction on the surface of the substrate on the susceptor 3 held at a high temperature by, for example, resistance heating.

【0071】

On the other hand, a side flow gas containing no raw material gas is introduced from the side flow gas supply port 5, and an outlet is provided so as to flow along the inner wall of the reaction chamber 1 and the side surface of the susceptor 3.

【0072】

Further, in the configuration example of FIG. 9, the reaction chamber 1 is provided with a heater 7 for heating the wall surface, and the temperature of the wall surface of the reaction chamber 1 can be arbitrarily changed. That is, by raising the temperature of the wall surface by the heater 7, it is possible to promote the desorption of the raw material gas adsorbed on the inner wall of the reaction chamber 1 and the product due to the chemical reaction.

【0073】

Further, in the step of heating the wall surface and performing purging, by flowing the side flow gas, it is possible to promote the desorption of the raw material gas adsorbed on the inner wall and the product due to the chemical reaction more quickly and effectively. it can. Further, in the step of heating and purging the susceptor 3, the side flow gas flowing on the side surface of the susceptor 3 promotes the desorption of the raw material gas and the substance generated by the chemical reaction from the susceptor 3 and the like to perform the purging. Therefore, it is possible to prevent impurities such as water contained in the nitrogen compound raw material or the nitrogen compound raw material and the residual substance containing Al from being combined and incorporated into the active layer.

【0074】

In this way, by simultaneously performing the purging by heating the wall surface of the reaction chamber 1 and the purging by heating the susceptor 3, the effect of purging can be further enhanced, and a semiconductor light emitting device having a low threshold value can be grown.

【0075】

As described above, the fifth embodiment of the present invention relates to the method for manufacturing a semiconductor light emitting device according to any one of the first or second embodiments and the semiconductor light emitting device according to any third or fourth embodiment. In combination with the production method, the Al raw material, the Al reaction product, the Al compound, or Al is removed from the growth chamber wall and the susceptor.

【0076】

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

【0077】

FIG. 10 is a diagram showing an example of a surface emitting semiconductor laser manufactured by the method for manufacturing a semiconductor light emitting device and the apparatus for manufacturing a semiconductor light emitting device of the present invention. Referring to FIG. 10, 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.

【0078】

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.

【0079】

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.

【0080】

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.

【0081】

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.

【0082】

Further, in this example, it was decided to perform purging between the growth of the lower spacer layer 53 and the growth of the n-type semiconductor multilayer film reflector 52.

【0083】

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.

【0084】

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.

【0085】

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 reflector, and in the VCSEL on a GaAs substrate, this AlGaAs / GaAs laminated semiconductor is used. A 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 was improved due to the reasons described above. It decreased, and it was not possible to obtain an element with a low threshold current. However, 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 manufactured even by using an AlGaAs / GaAs laminated semiconductor multilayer film reflector 52. be able to.

【0086】

Further, in the present invention, an optical transmission module, an optical transmission / reception module, or an optical communication system using a surface emitting semiconductor laser element manufactured by the method for manufacturing a semiconductor light emitting device according to each of the above-described embodiments is constructed. Can be done.

【0087】

FIG. 11 is a diagram showing an example of an optical transmission module according to the present invention. Further, FIG. 12 is a diagram showing an example of an optical transmission / reception module according to the present invention.

【0088】

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. 11 and 12, 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.

【0089】

For example, a surface-emitting laser using GaInNAs is an element that can obtain oscillation in the 1.2-1.3 μm band or a longer wavelength band, and at these wavelengths, there is little loss to quartz-based optical fibers. For some reason, it is said to be suitable as a light source for communication. 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.

【0090】

According to the present invention, since an active layer containing high-quality N 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.

【0091】

[Effect of the invention]

As described above, according to the invention of claim 1, 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. In the method for manufacturing a semiconductor light emitting element to be grown using a nitrogen compound raw material and an organic metal Al raw material, respectively, after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown, the growth chamber wall Purging is performed by keeping the temperature higher than the temperature of the growth chamber wall when growing the active layer containing nitrogen, and purging is performed to grow the Al raw material, the Al reaction product, the Al compound, or Al on the growth chamber wall. By removing from, 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 substrate, and it is possible to grow a low threshold semiconductor light emitting element. ..

【0092】

Further, according to the invention of 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 each used as a nitrogen compound raw material. In the method for manufacturing a semiconductor light emitting element to be grown using an organic metal Al raw material, the temperature of the growth chamber wall is set to the temperature of the nitrogen after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. The active layer containing the active layer is kept at a temperature higher than the temperature of the growth chamber wall when growing, and side flow gas is flowed along the growth chamber wall to perform purging, and the Al raw material, Al reaction product, or Al is performed. By removing the compound or Al from the growth chamber wall, it is possible to further 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 incorporated into the substrate. A low threshold semiconductor light emitting element can be grown.

【0093】

Further, according to the invention of claim 3, 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 each used as a nitrogen compound raw material. In the method for manufacturing a semiconductor light emitting element to be grown using the organic metal Al raw material, the temperature of the susceptor holding the substrate is set after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. By keeping the temperature of the active layer containing nitrogen higher than the temperature of the susceptor when growing it and purging it, and removing the Al raw material, the Al reaction product, the Al compound, or Al from the susceptor, Al It is possible to prevent the substance containing the above from coming into contact with the nitrogen compound raw material or the impurities contained in the nitrogen compound raw material and being incorporated into the substrate, and it is possible to grow a semiconductor light emitting element having a low threshold value.

【0094】

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 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 to be grown using the organic metal Al raw material, the temperature of the susceptor holding the substrate is set after the semiconductor layer containing Al is grown and before the active layer containing nitrogen is grown. The temperature of the active layer containing nitrogen is kept higher than the temperature of the susceptor when growing, and the side flow gas is flowed along the susceptor to perform purging. Alternatively, by removing Al from the susceptor, it is possible to further 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 incorporated into the substrate, and the semiconductor has a low threshold value. The light emitting element can be grown.

【0095】

Further, according to the invention according to claim 5, the method for manufacturing a semiconductor light emitting element according to any one of claims 1 or 2 and the method according to any one of claims 3 or 4. The Al raw material, the Al reactant, the Al compound, or Al is removed from the growth chamber wall and the susceptor in combination with the method for manufacturing a semiconductor light emitting element, according to claim 1 or 2. By combining any of these with either claim 3 or claim 4, the Al source, or Al reactant, or Al compound, or Al can be removed from both the growth chamber wall and the susceptor. As a result, it is possible to further 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 incorporated into the substrate, and it is possible to grow a low threshold semiconductor light emitting element.

【0096】

Further, according to the invention of claim 6, the surface emitting semiconductor laser device is produced by the method for manufacturing a semiconductor light emitting device according to any one of claims 1 to 5. Therefore, it is possible to grow (provide) a low-threshold surface-emitting semiconductor laser device composed of an active layer containing N such as GaInNAs even by using an AlGaAs / GaAs laminated semiconductor multilayer film reflector.

【0097】

Further, according to the invention of claim 7, since the optical transmission module is characterized in that the surface emitting semiconductor laser device of claim 6 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.

【0098】

Further, according to the invention of claim 8, since the optical transmission / reception module is characterized in that the surface emitting semiconductor laser device of claim 6 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.

【0099】

Further, according to the invention of claim 9, since the optical communication system is characterized in that the surface emitting semiconductor laser device of claim 6 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]

It is a figure which shows the distribution in the depth direction of a nitrogen (N) concentration and an oxygen (O) concentration when the semiconductor light emitting device of FIG. 2 is 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 which shows the structural example of the manufacturing apparatus of the semiconductor light emitting element of the 2nd Embodiment of this invention.

[Fig. 6]

It is a figure which shows the structural example of the manufacturing apparatus of the semiconductor light emitting element of the 3rd Embodiment of this invention.

[Fig. 7]

It is a figure which shows the structural example of the manufacturing apparatus of the semiconductor light emitting element of 4th Embodiment of this invention.

[Fig. 8]

It is a figure which shows the modification of the manufacturing apparatus of the semiconductor light emitting element of FIG.

[Fig. 9]

It is a figure which shows the structural example of the manufacturing apparatus of the semiconductor light emitting element of 5th Embodiment of this invention.

[Fig. 10]

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. 11]

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

[Fig. 12]

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

[Explanation of symbols]

1 Reaction chamber (growth chamber) 2 board 3 susceptor 4 Raw material gas supply port 5 Side flow gas supply port 6 Gas exhaust port 7 heater 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