JP2011040487A - Method for manufacturing group-iii nitride semiconductor light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress variations of light emitting wavelength, in a method for manufacturing a group-III nitride semiconductor light emitting element, by reducing warpage of a wafer in formation of a light emitting layer. <P>SOLUTION: A curvature lessening layer composed of n-AlGaN is inserted to an n-contact layer 11 composed of n-GaN. Although a stress warping a wafer is produced due to difference in coefficient of thermal expansion and difference in lattice constant between a sapphire substrate 10 and the n-contact layer 11 in formation of the light emitting layer 15, the insertion of the curvature lessening layer 12 causes a stress in the opposite direction to this stress. Accordingly, the warpage of the wafer is lessened. As a result, variations of composition and thickness of the light emitting layer 15 are reduced, and the variations of light emitting wavelength are reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a group III nitride semiconductor light emitting device capable of suppressing warpage of a wafer when forming a light emitting layer.

  When a group III nitride semiconductor light emitting device is manufactured using a sapphire substrate, first, an n layer is formed on the sapphire substrate via a buffer layer, and then a group III nitride semiconductor layer containing In is included. A light emitting layer is formed. At this time, the n layer is formed at a growth temperature of about 1000 to 1100 ° C., whereas the light emitting layer is formed at a growth temperature of 700 to 800 ° C. in order to suppress the separation of In and improve crystallinity. It is necessary to lower the temperature when forming the layer.

  However, when the temperature is lowered from 1000 to 1100 ° C. to 700 to 800 ° C., the wafer warps in a convex shape toward the n layer side due to the influence of the difference in thermal expansion coefficient and lattice constant between the sapphire substrate and the n layer. . When the wafer is warped in this manner, the central portion of the wafer is slightly lifted from the susceptor, and heat is not evenly transferred from the susceptor to the wafer, and the temperature distribution in the wafer surface is biased. When the light emitting layer is formed in such a state where the temperature distribution is biased, the composition and thickness of the light emitting layer vary, and as a result, the light emission wavelength within the wafer surface varies.

  There are Patent Documents 1 and 2 as techniques for suppressing the warpage of the wafer when forming the light emitting layer as described above. Patent Document 1 discloses a method of reducing warpage by forming a groove in a sapphire substrate and absorbing the difference in thermal expansion by the groove. Patent Document 2 discloses two methods: a method of suppressing warpage by increasing the thickness of the sapphire substrate, and a method of grasping the warpage of the wafer by observing Newton rings and adjusting the temperature according to the state of warpage. ing.

JP 2000-174335 A JP 2006-156454 A

  However, when a groove is formed in a sapphire substrate as in Patent Document 1, the light emitting layer is formed in an uneven shape along the groove, resulting in variations in the thickness and composition ratio of the light emitting layer, and the emission wavelength within the wafer surface. It is not possible to suppress the variation of.

  Further, in the method of increasing the thickness of the sapphire substrate as in Patent Document 2, the subsequent chip formation process is difficult, and it takes time to reduce the thickness of the sapphire substrate, and it is necessary to remove the sapphire substrate, resulting in a long manufacturing time. And multi-step process. Further, as a method for adjusting the temperature according to the state of warpage, there is no description in Patent Document 2 as to how the temperature distribution in the wafer surface can be controlled by specifically controlling the temperature. Is practically difficult.

  Accordingly, an object of the present invention is to provide a method for manufacturing a group III nitride semiconductor light emitting device capable of suppressing wafer warpage during formation of a light emitting layer by a simple method and suppressing variations in emission wavelength within the wafer surface. It is in.

  In a first invention, an n layer, a light emitting layer, and a p layer made of a group III nitride semiconductor are sequentially formed on a sapphire substrate, and the light emitting layer is formed at a temperature lower than the formation temperature of the n layer. A method for manufacturing a group III nitride semiconductor light-emitting device, characterized in that a bending relaxation layer made of a group III nitride semiconductor having a lattice constant smaller than that of the n layer is formed in the n layer. It is.

Here, the group III nitride semiconductor is a compound semiconductor represented by the general formula Al _x Ga _y In _z N (x + y + z = 1, 0 ≦ x, y, z ≦ 1), and includes Al, Ga, and In. It also includes those in which part is substituted with other group 13 elements B and Tl, and part of N is substituted with other group 15 elements P, As, Sb, and Bi. Usually, Si is used for n-type impurities, and Mg is used for p-type impurities. In the group III nitride semiconductor, the lattice constant decreases as the Al composition ratio increases, and the lattice constant increases as the In composition ratio increases.

  The “n layer formation temperature” referred to in the present invention is the lowest formation temperature among the layer formation temperatures when the n layer is composed of a plurality of layers and the formation temperatures of these layers are different. Say. In the present invention, “the light emitting layer is formed at a temperature lower than the formation temperature of the n layer” means that the light emitting layer is a multi-layer such as an MQW structure and the formation temperature of these layers is different. This refers to the case where the lowest formation temperature among the layer formation temperatures is lower than the “n layer formation temperature”.

  In addition, “the lattice constant is smaller than that of the n layer” means that when the n layer is composed of a plurality of layers having different lattice constants, the lattice constant is the smallest among the plurality of layers constituting the n layer. It means that the lattice constant is smaller than that of the layer.

  The bending relaxation layer may be made of a group III nitride semiconductor having a lattice constant smaller than that of the n layer. It is desirable that the lattice constant, thickness, and insertion position of the bending relaxation layer have values that allow the wafer to be flattened when the temperature is lowered to the formation temperature of the light emitting layer after forming the n layer. The lattice constant of the bending relaxation layer can be controlled by the composition ratio of Al, Ga, and In, and the lattice constant may be controlled by other impurities. In particular, ternary AlGaN is desirable because of its ease of formation and easy adjustment of the composition ratio.

  When the bending relaxation layer is made of AlGaN, the Al composition ratio, thickness, and insertion position of the bending relaxation layer are the values at which the wafer is flattened when the temperature is lowered to the formation temperature of the light emitting layer after forming the n layer. It is desirable to be. The Al composition ratio is desirably 20 to 100%. If the Al composition ratio is lower than this, it is not desirable because the effect of reducing the warpage of the wafer is not sufficient. A more desirable Al composition ratio is 30 to 40%. Further, the thickness of the bending relaxation layer is desirably 100 mm or less. If the thickness is too thick, the stress in the opposite direction to the warp caused by the insertion of the bending relaxation layer is too large, which is not desirable because the wafer warps in the opposite direction. More preferably, it is 20-40cm. The position of the bending relaxation layer in the n layer is preferably 20% to 80% with respect to the thickness of the n layer from the n layer side surface of the sapphire substrate. If it is this range, a curvature can be reduced favorably at the time of light emitting layer formation.

  The growth temperature of the bending relaxation layer is preferably close to the formation temperature of the n layer. Further, the bending relaxation layer 12 may be doped with an n-type impurity.

  The detailed configuration of the n layer may be various configurations conventionally known. For example, an n contact layer and an n clad layer may be formed in this order from the sapphire substrate side, and an ESD layer may be provided between the n contact layer and the n clad layer in order to enhance electrostatic withstand voltage characteristics. You may have the structure. When the n layer has such a configuration, the bending relaxation layer is usually inserted into the n contact layer. Furthermore, the n contact layer, ESD layer, and n clad layer may be composed of a plurality of layers having different n-type impurity concentrations and compositions, and may have a superlattice structure.

  The light emitting layer usually has an MQW structure in which a well layer and a barrier layer are repeatedly formed, but may have an SQW structure or the like.

  The p layer may also have various conventionally known configurations. For example, a p-cladding layer and a p-contact layer are sequentially formed from the light emitting layer side. The p-clad layer and the p-contact layer may be composed of a plurality of layers having different p-type impurity concentrations and compositions, and may have a superlattice structure.

  When the n layer is exposed by etching from the p layer surface side and an n electrode is provided on the exposed n layer, the n electrode is preferably provided in contact with the n layer between the bending relaxation layer and the light emitting layer. . Providing an n electrode in contact with the n layer between the bending relaxation layer and the sapphire substrate is not desirable because current flows through the bending relaxation layer and the drive voltage increases.

  According to a second invention, in the first invention, the n layer has a configuration in which an n contact layer and an n cladding layer are formed in this order from the sapphire substrate side, the n contact layer is n-GaN, and the bending relaxation layer is The method of manufacturing a group III nitride semiconductor light-emitting device, wherein the bending relaxation layer is formed of n-AlGaN and formed in the n-contact layer.

  A third invention is the method for producing a group III nitride semiconductor light emitting device according to the second invention, wherein the bending relaxation layer has a thickness of 100 mm or less.

  A fourth invention is a method for producing a group III nitride semiconductor light emitting device according to the second invention or the third invention, wherein the Al composition ratio of the bending relaxation layer is 20 to 100%.

  In a fifth aspect based on the second aspect to the fourth aspect, the bending relaxation layer has a thickness of 20 to 80% of the thickness of the n layer from the interface between the sapphire substrate and the n layer to the light emitting layer side. The method of manufacturing a group III nitride semiconductor light-emitting device, characterized by being formed at a position of

  According to the present invention, by providing a bending relaxation layer made of a group III nitride semiconductor having a lattice constant smaller than that of the n layer in the n layer, the thermal expansion coefficient difference between the sapphire substrate and the n layer is caused by the lattice constant difference. Since stress is generated in a direction opposite to the stress to be generated, the warpage of the wafer when the temperature is set to form the light emitting layer can be reduced. Thus, heat is evenly transmitted to the wafer and the uneven temperature distribution is eliminated, so that the light emitting layer can be formed while suppressing variations in thickness and composition. As a result, variation in emission wavelength can be suppressed, and yield is improved. Further, in the present invention, if the lattice constant, the thickness, and the insertion position of the bending relaxation layer are adjusted according to the diameter and thickness of the sapphire substrate, the thickness and formation temperature of the n layer, and the formation temperature of the light emitting layer, light emission Wafer warpage during layer formation can be reduced, and variations in emission wavelength can be further reduced.

The figure shown about the manufacturing process of the group III nitride semiconductor light-emitting device. The figure shown about the manufacturing process of the group III nitride semiconductor light-emitting device. The figure shown about the manufacturing process of the group III nitride semiconductor light-emitting device. The figure shown about the manufacturing process of the group III nitride semiconductor light-emitting device. The figure shown about the manufacturing process of the group III nitride semiconductor light-emitting device. The figure shown about the manufacturing process of the group III nitride semiconductor light-emitting device. The graph shown about light emission wavelength distribution. The graph shown about light emission wavelength distribution. The graph shown about light emission wavelength distribution.

  Hereinafter, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the examples.

  A method for manufacturing the Group III nitride semiconductor light-emitting device of Example 1 will be described with reference to FIG.

First, a sapphire substrate 10 having a thickness of 500 μm and a diameter of 3 inches was prepared, and the sapphire substrate 10 was cleaned by heating in a hydrogen atmosphere to remove deposits on the surface of the sapphire substrate 10. . Thereafter, an n contact layer 11 made of n-GaN doped with Si was formed at 1000 to 1100 ° C. on the surface of the sapphire substrate 10 on the unevenness forming side of the sapphire substrate 10 by a MOCVD method through a buffer layer (not shown) made of AlN. . Hydrogen and nitrogen were used for the carrier gas, ammonia was used for the nitrogen source, TMG (trimethylgallium) was used for the Ga source, TMA (trimethylaluminum) was used for the Al source, and SiH ₄ (silane) was used for the n-type dopant source (see FIG. 1. A).

  Subsequently, a bending relaxation layer 12 made of non-doped AlGaN was formed at a temperature of 950 ° C. by MOCVD. The carrier gas, nitrogen source, Ga source, Al source, and n-type dopant source gas are the same as when the n-contact layer 11 is formed. The thickness of the bending relaxation layer 12 is 20 to 40 mm, and the Al composition ratio is 20 to 40%. The formation temperature of the bending relaxation layer 12 is preferably as close to the formation temperature of the n contact layer 11 as possible for the purpose of reducing the warpage of the wafer.

  Subsequently, the n contact layer 11 was formed again on the bending relaxation layer 12 by MOCVD. As a result, a structure in which the bending relaxation layer 12 was inserted into the n contact layer 11 was formed (FIG. 1.B). The thickness of the n contact layer 11 is 5.1 μm, and the insertion position of the bending relaxation layer 12 is n contact from the surface of the sapphire substrate 10 on the side where the n contact layer 11 is formed toward the n contact layer 11. The position of the thickness of 30 to 60 percent of the thickness of the layer 11, that is, the position of 1.53 to 3.06 μm.

  Next, an ESD layer 13 was formed at 850 ° C. on the n-contact layer 11 by MOCVD, and an n-cladding layer 14 was formed on the ESD layer 13 by MOCVD (FIG. 1.C). The ESD layer 13 is provided in order to improve electrostatic withstand voltage characteristics, and has a structure in which i-GaN and n-GaN are stacked from the n contact layer 11 side. The n-clad layer 14 has a superlattice structure in which i-GaN and i-InGaN are alternately and repeatedly formed. The i-GaN of the n-clad layer 14 is formed at 850 ° C. and i-InGaN is formed at 850 ° C. In the formation of the ESD layer 13 and the n-clad layer 14, the carrier gas, nitrogen source, Ga source, Al source, and n-type dopant source gas are the same as those used when the n-contact layer 11 is formed. (Trimethylindium) was used.

  Next, the light emitting layer 15 was formed on the n clad layer 14 by MOCVD (FIG. 1.D). The light emitting layer 15 has an MQW structure in which InGaN and AlGaN are alternately and repeatedly stacked. InGaN is formed at 700 to 900 ° C., and AlGaN is formed at 800 to 950 ° C. The carrier gas, nitrogen source, Ga source, Al source, and In source gas are the same as when the n-clad layer 14 is formed.

  Here, since the formation temperature of the n-contact layer 11 is 1000 to 1100 ° C. and the formation temperature of InGaN of the light emitting layer 15 is 700 to 900 ° C., thermal expansion between the sapphire substrate 10 and the n-contact layer 11 is performed. Due to the difference in coefficient and the difference in lattice constant, a stress that warps the wafer convexly from the sapphire substrate 10 toward the n-contact layer 11 occurs. On the other hand, since the bending relaxation layer 12 made of AlGaN having a smaller lattice constant than the n contact layer 11 made of GaN is inserted into the n contact layer 11, it is caused by the difference in lattice constant between the n contact layer 11 and the bending relaxation layer 12. Thus, stress is generated in the direction opposite to the direction in which the wafer is warped. Since part or all of the stress that causes the wafer to be convexly convex can be canceled by this stress, the warpage of the wafer is reduced when the light emitting layer 15 is formed. As a result, variations in temperature distribution in the wafer surface are reduced, and variations in the composition and thickness of the light emitting layer 15 are also reduced. The amount of warpage of the wafer when the light emitting layer 15 is formed includes the thickness and diameter of the sapphire substrate 10, the formation temperature and thickness of the sapphire substrate 10 from the n contact layer 11 side surface to the n cladding layer 14, and the light emitting layer 15. It can be reduced by adjusting the lattice constant, thickness, and insertion position of the bending relaxation layer 12 according to the forming temperature.

Next, an Mg-doped p clad layer 16 and a p contact layer 17 were formed on the light emitting layer 15 by MOCVD (FIG. 1.E). The p-cladding layer 16 has a superlattice structure in which, for example, Mg-doped InGaN and Mg-doped AlGaN are alternately and repeatedly formed. The p contact layer 17 is Mg-doped GaN. The carrier gas, nitrogen source, Ga source, Al source, and In source gas were the same as described above, and Cp ₂ Mg (biscyclopentadienyl magnesium) was used as the p-type dopant source.

  Next, Mg is activated by heat treatment to be p-type, and then reaches a predetermined region from the surface of the p contact layer 17 to the n contact layer 11 in a region sandwiched between the bending relaxation layer 12 and the ESD layer 13. The groove was formed by dry etching. Then, a transparent electrode 18 made of ITO is formed on almost the entire surface of the p contact layer 17, a p electrode 19 is formed on the transparent electrode 18, and an n electrode 20 is formed on the n contact layer 11 exposed by the groove ( Figure 1.F). Here, the depth of the groove for forming the n-electrode 20 is set to a depth that reaches the n contact layer 11 in a region sandwiched between the bending relaxation layer 12 and the sapphire substrate 10 through the bending relaxation layer 12. Not desirable. This is because problems such as an increase in driving voltage occur because current flows through the bending relaxation layer 12. Further, the p-electrode 19 may be formed in a wiring pattern such as a lattice shape or a comb tooth shape in order to improve the current diffusibility in the element surface direction. The above is the manufacturing process of the group III nitride semiconductor light-emitting device of Example 1.

  FIG. 2 shows the emission wavelength of each group III nitride semiconductor light-emitting element obtained from the same wafer when the thickness of the bending relaxation layer 12 is 20 mm and 40 mm and when the bending relaxation layer 12 is not provided. The ratio of the number of elements for each emission wavelength with respect to the total number of elements obtained from the same wafer is shown in a graph. The composition ratio of Al in the bending relaxation layer 12 was 30%, and the insertion position of the bending relaxation layer 12 was 3 μm deep from the interface between the ESD layer 13 and the n contact layer 11 in the direction of the sapphire substrate 10. Further, when the standard deviation of the emission wavelength is obtained from the emission wavelength distribution of FIG. 2, the standard deviation is 2.97 nm when the bending relaxation layer 12 is not provided, and the standard deviation is 2.47 nm when the 20 mm bending relaxation layer 12 is inserted. When the 40 mm bending relaxation layer 12 was inserted, the standard deviation was 1.58 nm.

  From the result of the emission wavelength distribution of FIG. 2, it can be seen that when the bending relaxation layer 12 is not provided, the emission wavelength and the composition of the emission layer 15 vary within the wafer surface, and the wafer is warped when the emission layer 15 is formed. It is assumed that the temperature distribution in the wafer surface was uneven. In addition, when the 20 mm bending relaxation layer 12 is inserted, the variation in the emission wavelength and the variation in the composition of the light emitting layer are slightly reduced as compared with the case where the bending relaxation layer 12 is not provided. It can be seen that it has been reduced. This is because stress due to a difference in lattice constant between the n contact layer 11 and the bending relaxation layer 12 is generated by inserting the bending relaxation layer 12 made of AlGaN having a lattice constant smaller than that of the n contact layer 11. Is in the direction opposite to the stress caused by the difference in thermal expansion coefficient and the lattice constant between the sapphire substrate 10 and the n-contact layer 11, which is considered to be the result of relaxing the warpage of the wafer. Then, it is considered that the unevenness of the temperature distribution in the wafer surface is alleviated by suppressing the warpage, and the variation in the composition of the light emitting layer is suppressed. Further, it is considered that the thicker the bending relaxation layer 12, the greater the stress generated in the direction opposite to the direction in which the wafer is warped, and the higher the effect of relaxing the warp. However, if the bending relaxation layer 12 is too thick, the generated stress is too large and the wafer is warped in the opposite direction, which may cause the wavelength to vary. Further, since the bending relaxation layer 12 is made of AlGaN, if it is formed thick, there is a possibility that problems such as an increase in driving voltage occur due to poor crystallinity. Therefore, it seems that the thickness of the bending relaxation layer 12 is desirably 100 mm or less.

  To summarize the considerations from the results of FIG. 2, in order to suppress variations in the emission wavelength in the wafer surface, the thickness of the bending relaxation layer 12 is preferably 100 mm or less, and more preferably 20 to 40 mm. I understood.

  FIG. 3 shows the respective group III nitrides obtained from the same wafer when the Al composition ratio of the bending relaxation layer 12 made of AlGaN is 20%, 30%, and 40% and when the bending relaxation layer 12 is not provided. The light emission wavelength of a physical semiconductor light emitting element is examined, and the ratio of the number of elements for each emission wavelength to the total number of elements obtained from the same wafer is shown in a graph. The thickness of the bending relaxation layer 12 was 40 mm, and the insertion position of the bending relaxation layer 12 was 3 μm deep from the interface between the ESD layer 13 and the n contact layer 11. When the standard deviation of the emission wavelength is obtained from the emission wavelength distribution of FIG. 3, the standard deviation is 2.97 nm when the bending relaxation layer 12 is not provided, and the standard deviation is 2 when the bending relaxation layer 12 with an Al composition ratio of 20% is inserted. When the bending relaxation layer 12 having a thickness of 0.05 mm and an Al composition ratio of 30% was inserted, the standard deviation was 1.58 nm. When the bending relaxation layer 12 having an Al composition ratio of 40% was inserted, the standard deviation was 1.44 nm.

  From the result of the emission wavelength distribution of FIG. 3, when the bending relaxation layer 12 with an Al composition ratio of 20% is inserted, the variation in the emission wavelength and the variation in the composition of the light emitting layer are slightly reduced as compared with the case where the bending relaxation layer 12 is not provided. It can be seen that when the bending relaxation layer 12 having an Al composition ratio of 30 and 40% is inserted, the variation is further reduced. This is considered to be because the larger the Al composition ratio, the larger the lattice constant difference from the n-contact layer 11 made of GaN, and the greater the stress in the direction opposite to the stress causing the warpage of the wafer. . Further, if the Al composition ratio exceeds a certain value, the stress caused by the insertion of the bending relaxation layer 12 becomes larger than the stress causing the warp of the wafer, and the wafer is warped in reverse, so that the emission wavelength gradually increases. The variation is expected to increase.

  To summarize the considerations from the results of FIG. 3, in order to suppress the variation in the emission wavelength in the wafer surface, the Al composition ratio of the bending relaxation layer 12 is desirably 20 to 100%, and is preferably 30 to 40%. It turned out to be more desirable.

  4 shows the insertion position of the bending relaxation layer 12 at a depth of 2.0 μm, 2.5 μm, and 3.0 μm from the interface between the ESD layer 13 and the n contact layer 11 toward the n contact layer 11 (of the sapphire substrate 10). Each group III nitride obtained from the same wafer in the case of 3.1 μm, 2.6 μm, and 2.1 μm positions from the surface on the n contact layer 11 formation side and when the bending relaxation layer 12 is not provided The emission wavelength of the semiconductor light emitting element is examined, and the ratio of the number of elements for each emission wavelength with respect to the total number of elements obtained from the same wafer is shown in a graph. The Al composition ratio of the bending relaxation layer 12 was 30% and the thickness was 40 mm. In any case, the total thickness of the n-contact layer 11 is 5.1 μm and is not changed. In addition, the depths of 2.0 μm, 2.5 μm, and 3.0 μm from the interface between the ESD layer 13 and the n contact layer 11 in the direction of the n contact layer 11 are respectively about the total thickness of the n contact layer 11. The depth is 40%, about 50%, and about 60%.

  From the result of the emission wavelength distribution of FIG. 4, it can be seen that the deeper the insertion position of the bending relaxation layer 12, that is, the closer to the sapphire substrate 10, the smaller the emission wavelength variation and the emission layer composition variation. This is presumably because the thicker the n-contact layer 11 is, the greater the stress that warps the wafer is. Therefore, inserting the bending relaxation layer 12 at a position close to the sapphire substrate 10 increases the effect of reducing the warp. However, if the position of the bending relaxation layer 12 from the surface of the sapphire substrate 10 is smaller than 20% with respect to the total thickness of the n contact layer 11, the sapphire substrate 10 is processed to be uneven, so that the n contact layer 11 is sufficient. Therefore, the bending relaxation layer 12 is formed before being flattened. When the position of the bending relaxation layer 12 from the surface of the sapphire substrate 10 is larger than 80% with respect to the entire thickness of the n contact layer 11, the n contact layer 11 between the bending relaxation layer 12 and the sapphire substrate 10. Since the thickness of the film becomes thick, the stress that warps the wafer is large, and the curvature relaxation layer 12 cannot sufficiently reduce the warp.

  Therefore, in order to suppress the variation in the emission wavelength in the wafer surface, the position of the bending relaxation layer 12 from the surface of the sapphire substrate 10 is set to a position of 20% to 80% with respect to the thickness of the n contact layer 11. Is desirable, and it is more desirable to set it at a position of 50 to 60 percent.

  Further, when it was confirmed whether or not the driving voltage in the wafer surface changes due to the insertion of the bending relaxation layer 12, the average driving voltage at 20 mA hardly changes even when the bending relaxation layer 12 is inserted, and the standard deviation of the driving voltage. Was almost unchanged. Further, when the variation in the reverse current at −5 V in the wafer surface was examined, it was found that when the bending relaxation layer 12 was inserted, the variation in the reverse current was reduced as compared with the case where the bending relaxation layer 12 was not inserted.

  In the embodiment, AlGaN is used as the bending relaxation layer 12, but a group III nitride semiconductor having a lattice constant smaller than that of the n contact layer 11 may be used. For example, AlGaInN may be used.

  The method for producing a Group III nitride semiconductor light-emitting device of the present invention is effective for suppressing variation in wavelength, and is particularly effective when a large-diameter substrate is used or when the Group III nitride semiconductor layer is made thick. is there.

10: sapphire substrate 11: n contact layer 12: bending relaxation layer 13: ESD layer 14: n cladding layer 15: light emitting layer 16: p cladding layer 17: p contact layer 18: transparent electrode 19: p electrode 20: n electrode

Claims (5)

An n-layer, a light-emitting layer, and a p-layer made of a group III nitride semiconductor are sequentially formed on a sapphire substrate, and the light-emitting layer is formed at a temperature lower than the formation temperature of the n-layer. In the manufacturing method,
Forming a bending relaxation layer made of a group III nitride semiconductor having a lattice constant smaller than that of the n layer in the n layer;
A method for producing a Group III nitride semiconductor light-emitting device. The n layer has a configuration in which an n contact layer and an n clad layer are formed in this order from the sapphire substrate side,
The n-contact layer is n-GaN;
The bending relaxation layer is formed in the n-contact layer;
The method of manufacturing a group III nitride semiconductor light-emitting device according to claim 1, wherein the bending relaxation layer is made of n-AlGaN.   The method of manufacturing a group III nitride semiconductor light-emitting device according to claim 2, wherein the bending relaxation layer has a thickness of 100 mm or less.   4. The method for producing a group III nitride semiconductor light emitting device according to claim 2, wherein the Al composition ratio of the bending relaxation layer is 20 to 100%. 5.   The said bending relaxation layer is formed in the position of 20 to 80% of thickness with respect to the thickness of the said n layer from the said n layer side surface of the said sapphire board | substrate. Item 5. A method for manufacturing a Group III nitride semiconductor light-emitting device according to any one of Items 4 to 5.

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