JP2008160137A - Group iii nitride semiconductor, method for manufacturing same and semiconductor device using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing group III nitride semiconductor capable of manufacturing p-type group III nitride semiconductor with small deterioration and a low resistance of the surface. <P>SOLUTION: After group III nitride crystal 32 including at least both of a p-type impurity and hydrogen is grown and cooled, the group III nitride semiconductor is manufactured as the p-type type group III nitride semiconductor by forming a predetermined lamination structure 33 on the group III nitride crystal 32. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a group III nitride semiconductor that can be used for a light source for optical pickup such as DVD and CD, a writing light source for electrophotography, a light source for optical communication, an ultraviolet sensor, a high temperature operation transistor, and the like, a manufacturing method thereof, and a semiconductor device. .

  Conventionally, blue LEDs have lower brightness than red and green and have had difficulties in practical use. Recently, in group III nitride semiconductors represented by the general formula InAlGaN, low-temperature AlN buffer layer or low-temperature GaN buffer layer As a result of improvement of crystal growth technology by using a low-resistance p-type semiconductor layer with Mg as a dopant, a high-intensity blue LED has been put to practical use. An oscillating semiconductor laser has been put into practical use.

  As an important technology of the group III nitride semiconductor, there is a manufacturing technology of p-type group III nitride. As this manufacturing technique, there is a method such as MOCVD using hydrogen as a carrier gas. However, the p-type group III nitride contains hydrogen because the p-type impurity and hydrogen are combined to inactivate the impurity. The resistance increases when crystal growth in an atmosphere or heat treatment in a gas that generates hydrogen or hydrogen is performed. Therefore, it has been difficult to produce p-type group III nitride without any treatment (as grown) by a method such as MOCVD using hydrogen as a carrier gas.

  For this reason, as a method for producing a p-type group III nitride, there are a first method in which a high-resistance group III nitride is p-typed by performing a special treatment, and hydrogen is converted into a p-type impurity during the cooling step. It is roughly divided into a second method for producing p-type group III nitride by devising the crystal growth process so as to prevent bonding (see FIG. 15).

  As the first method, those disclosed in JP-A-5-183189 (hereinafter referred to as Conventional Technology 1) or JP-A-3-218625 (hereinafter referred to as Conventional Technology 2) are known. Yes. That is, in prior art 1, as shown in FIG. 16, heat treatment is performed in an atmosphere gas that does not substantially contain hydrogen or a gas that generates hydrogen, and a part of hydrogen H in the GaN crystal is diffused and discharged out of the GaN crystal. Thus, the p-type has a low resistance. In the prior art 2, a low-energy electron beam is irradiated to cut off the bond between hydrogen and p-type impurities so that the p-type has a low resistance.

As a second method, as shown in Japanese Patent Laid-Open No. 8-125222 (hereinafter referred to as Prior Art 3), the cooling after completion of the GaN crystal growth is performed by using an atmosphere not containing hydrogen or an inert gas. This is done in a low resistance p-type.
JP-A-5-183189 JP-A-3-218625 JP-A-8-125222

  In the prior art 1 described above, in order to discharge hydrogen deactivating p-type impurities to the outside of the crystal by heat treatment, heat treatment is performed at a temperature of, for example, 700 ° C. in an atmosphere not containing hydrogen, generally a nitrogen gas atmosphere. To do. However, in a nitrogen gas atmosphere, nitrogen gas composed of nitrogen molecules does not become a raw material for generating group III nitride, and therefore, the surface resistance increases due to decomposition of the group III nitride crystal surface at a temperature higher than 700 ° C. In some cases, deterioration of characteristics may occur.

  In addition, in the experiment by the inventors of the present application, the hydrogen concentration is reduced by the heat treatment, but the hydrogen concentration distribution is similar to the concentration distribution before the heat treatment, and the concentration is highest near the surface, so that the electrode The contact resistivity was not necessarily low.

  Further, in the prior art 3, when the temperature drop from the crystal growth temperature of about 1000 ° C. to room temperature is performed in a nitrogen gas atmosphere or an inert gas only atmosphere, the crystal surface is decomposed and the surface resistance is increased. In some cases, the characteristics deteriorated.

  In the prior art 2, low-energy electron beam is irradiated, but low-energy electron beam irradiation has a shallow penetration depth of electron beam and can only be made p-type in the vicinity of the crystal surface. Since the area that can be formed is narrow, it takes time to make the entire wafer surface p-type, and there is a problem that it is industrially expensive.

  On the other hand, it is known that low resistance p-type GaN can be obtained by the MBE method in which growth is performed only with raw materials not containing hydrogen.

  However, the MBE method has a problem that it is difficult to perform high-quality crystal growth, such as formation of defects due to dissociation of nitrogen in order to perform crystal growth in a high vacuum. In addition, there is a problem in supply of nitrogen, the growth rate is slow, and it is not suitable for mass production as compared with the MOCVD method.

  On the other hand, when the crystal growth is performed by the MOCVD method in an atmosphere containing as little hydrogen as in the MBE method, in the GaN experiment by the inventor of the present application, the surface has unevenness and a crystal with good crystallinity is grown. I couldn't. That is, high-quality p-type GaN cannot be grown in an atmosphere that does not contain hydrogen.

  The present invention provides a group III nitride semiconductor manufacturing method, a group III nitride semiconductor, and a semiconductor device capable of manufacturing a p-type group III nitride semiconductor with low surface degradation and low resistance. It is an object.

  Another object of the present invention is to provide a semiconductor device with low cost, high reliability, and low operating voltage.

  In order to achieve the above object, according to the first aspect of the present invention, after a group III nitride crystal containing at least both p-type impurities and hydrogen is grown and cooled, on the group III nitride crystal, The group III nitride crystal is manufactured as a p-type group III nitride semiconductor by forming a predetermined laminated structure.

  According to a second aspect of the present invention, in the method for manufacturing a group III nitride semiconductor according to the first aspect, the predetermined laminated structure has a thickness of 0.5 μm or more.

According to a third aspect of the present invention, there is provided a gas atmosphere containing a nitrogen source containing NH ₃ after crystal growth of a p-type group III nitride semiconductor containing at least p-type impurities in an atmosphere containing hydrogen gas. It is characterized by lowering the temperature from the growth temperature.

  According to a fourth aspect of the present invention, in the method for manufacturing a group III nitride semiconductor according to the first aspect, the outermost surface layer of the predetermined laminated structure is formed of a layer that can be grown in an atmosphere not containing hydrogen gas. It is characterized by doing.

  According to a fifth aspect of the present invention, in the method for producing a group III nitride semiconductor according to the fourth aspect, the outermost surface layer of the predetermined laminated structure is a group III nitride containing at least In. After the completion of crystal growth of the group III nitride containing at least In, the group III nitride containing nitrogen is grown in an atmosphere that does not contain hydrogen gas or in an atmosphere in which the nitrogen source gas and nitrogen gas are excessive with respect to the hydrogen gas. And cooling in a gas atmosphere containing at least a nitrogen raw material.

  According to a sixth aspect of the present invention, in the method for manufacturing a group III nitride semiconductor according to any one of the first to fifth aspects, the p-type impurity is Mg.

  The invention as set forth in claim 7 is characterized by a group III nitride semiconductor manufactured by the method for manufacturing a group III nitride semiconductor according to any one of claims 1 to 5.

  The invention according to claim 8 is characterized in that in the semiconductor device having at least a p-type semiconductor layer, the group III nitride semiconductor according to claim 7 is used for the p-type semiconductor layer.

  The invention described in claim 9 includes the p-type group III nitride semiconductor manufactured by the manufacturing method according to claim 5 and all or part of the p-type group III nitride laminated structure. The semiconductor device is characterized in that a p-side ohmic electrode is formed on the surface of the group nitride structure.

  According to a tenth aspect of the present invention, in the semiconductor device according to the eighth or ninth aspect, the semiconductor device is a semiconductor light emitting element.

  The invention according to claim 11 is the semiconductor device according to any one of claims 8 to 10, wherein the semiconductor device is a semiconductor electronic device.

  According to a twelfth aspect of the present invention, in the semiconductor device according to any one of the eighth to tenth aspects, the semiconductor device is a semiconductor light receiving element.

  As described above, according to the first aspect of the present invention, a group III nitride crystal containing at least both p-type impurities and hydrogen is grown and cooled, and then a predetermined laminated structure is laminated. Since the group III nitride crystal is manufactured as a p-type group III nitride semiconductor, the hydrogen contained in the group III nitride crystal in the stack of a predetermined layered structure (for example, group III nitride stacked structure) is III The group III nitride crystal is released out of the group, the resistance of the group III nitride crystal is reduced, and the group III of hydrogen from the atmosphere in the cooling process after the lamination of the predetermined laminated structure (for example, the group III nitride laminated structure) is completed. Diffusion penetration into the nitride crystal is prevented with a predetermined laminated structure, and the group III nitride crystal does not increase in resistance. As a result, the group III nitride crystal becomes a low-resistance p-type group III nitride semiconductor. Therefore, if the method for producing a p-type group III nitride semiconductor according to claim 4 is used, a heat treatment step after crystal growth is not required as in the prior art, and a low resistance p is obtained without depending on the atmospheric gas composition of the heat treatment. A type III nitride semiconductor can be manufactured.

  According to the second aspect of the present invention, the thickness of the predetermined laminated structure is 0.5 μm or more (that is, the hydrogen diffusion depth in the cooling process is about 0.5 μm from the surface). (Thus, by increasing the thickness of the predetermined laminated structure), the predetermined laminated structure causes almost no diffusion of hydrogen into the group III nitride crystal, and has a low resistance p with little influence of high resistance. A type III nitride semiconductor can be manufactured.

  According to a third aspect of the present invention, a p-type group III nitride semiconductor containing at least a p-type impurity is grown in an atmosphere containing hydrogen gas, and after the crystal growth, the growth is performed in a gas atmosphere containing a nitrogen source. As the temperature drops, the atomic nitrogen supplied from the nitrogen source at the time of temperature reduction suppresses the decomposition of the III-nitride crystal surface, prevents high resistance due to defects, and suppresses the diffusion and penetration of hydrogen from the atmospheric gas. Therefore, an as-grown and low-resistance p-type group III nitride semiconductor can be obtained.

  In addition, a certain amount of hydrogen can be included in the gas atmosphere when the temperature is lowered (during cooling). In this case, the cleaning effect of hydrogen on unreacted organic raw materials and organic substances adsorbed on the crystal surface is achieved. The increase in surface resistance due to surface contamination can be prevented. This is an effect that cannot be obtained by the prior art.

In addition, by using a compound that generates hydrogen by its decomposition, such as NH ₃ , as a nitrogen source, the crystal surface decomposition suppression effect (the hydrogen diffusion suppression effect) by atomic nitrogen and hydrogen cleaning The effect is obtained at the same time.

  According to the invention of claim 4 or claim 5, in the method of manufacturing a group III nitride semiconductor according to claim 1, the outermost surface layer of the predetermined laminated structure is in an atmosphere not containing hydrogen gas. Since it is formed by a layer that can be grown (more specifically, in the Group III nitride semiconductor manufacturing method according to claim 10, the outermost surface layer of the predetermined laminated structure is a Group III nitride containing at least In, and In this case, the group III nitride containing at least In is crystal-grown in an atmosphere not containing hydrogen gas or in an atmosphere in which the nitrogen source gas and nitrogen gas are excessive with respect to the hydrogen gas, and the group III nitride containing at least In After the crystal growth is finished, cooling is performed in a gas atmosphere containing at least a nitrogen raw material), so that the crystallinity of the surface layer of the laminated structure is good, and a p-type group III nitride semiconductor having a much lower resistance can be manufactured. .

  In other words, when a group III nitride not containing In is grown in an atmosphere not containing hydrogen, it is difficult to manufacture a group with good crystallinity due to severe surface irregularities. On the other hand, a group III nitride containing In can be manufactured with good crystallinity even if crystal growth is performed in an atmosphere not containing hydrogen. Therefore, by growing a group III nitride containing In in an atmosphere containing almost no hydrogen, a crystal with good crystallinity and a small amount of hydrogen taken up during crystal growth (group III nitride crystal containing In) is obtained. Can be manufactured.

  In addition, the hydrogen incorporated into the group III nitride crystal during the growth of the group III nitride crystal is efficiently converted into the group III nitride during the growth of the group III nitride containing In in an atmosphere containing almost no hydrogen. Since it is released out of the crystal, the hydrogen concentration in the group III nitride crystal is lowered, and the resistance is further reduced. Further, at the time of cooling, the layered structure prevents the diffusion and penetration of hydrogen into the group III nitride crystal, so that the group III nitride crystal does not increase in resistance. As a result, an even lower resistance p-type group III nitride semiconductor can be manufactured.

  According to a sixth aspect of the present invention, in the method of manufacturing a group III nitride semiconductor according to any one of the first to twelfth aspects, since the p-type impurity is Mg, In addition, a low-resistance p-type group III nitride semiconductor can be manufactured.

  According to the invention described in claim 7, since it is a group III nitride semiconductor manufactured by the method for manufacturing a group III nitride semiconductor according to any one of claims 1 to 5, A p-type group III nitride semiconductor with little deterioration and low resistance can be provided.

  According to the eighth aspect of the present invention, in the semiconductor device having at least the p-type semiconductor layer, the group III nitride semiconductor according to the seventh aspect is used for the p-type semiconductor layer. A semiconductor device with high performance and low operating voltage can be provided.

  According to the invention described in claim 9, the p-type group III nitride semiconductor manufactured by the manufacturing method according to claim 5 and all or part of the p-type group III nitride laminated structure are provided, and p Since the p-side ohmic electrode is formed on the surface of the type III nitride laminated structure and the resistance of the p type III nitride semiconductor is low, a semiconductor device having a lower operating voltage can be provided.

  According to a tenth aspect of the present invention, in the semiconductor device according to the eighth or ninth aspect, since the semiconductor device is a semiconductor light emitting element (for example, a semiconductor laser), high output, high efficiency, and high reliability. A semiconductor light emitting device can be provided.

  According to an eleventh aspect of the present invention, in the semiconductor device according to any one of the eighth to tenth aspects, the semiconductor device is a semiconductor electronic device. Can be provided.

  According to a twelfth aspect of the present invention, in the semiconductor device according to any one of the eighth to tenth aspects, the semiconductor device is a semiconductor light receiving element. Can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First Embodiment FIG. 1 is a diagram showing a first embodiment of a method for producing a group III nitride semiconductor according to the present invention. Referring to FIG. 1, in this method of manufacturing a group III nitride semiconductor, group III nitride crystal 1 containing at least both a p-type impurity and hydrogen is grown (FIG. 1A), and then group III nitride is performed. The p-type group III nitride semiconductor 3 is manufactured by removing all or part of the surface layer 2 of the physical crystal 1 (FIG. 1B) (FIG. 1C). In the example of FIGS. 1B and 1C, a case where the entire surface layer 2 of the group III nitride crystal 1 is removed is shown.

  In the experiment by the inventors of the present application, the hydrogen (H) concentration in the group III nitride crystal containing the p-type impurity subjected to crystal growth and cooling after crystal growth in an atmosphere containing hydrogen gas is shown in FIG. As shown in a), the crystal surface was the highest and decreased as it moved into the crystal, and the concentration was constant inside the crystal.

FIGS. 17A and 17B show the results of SIMS analysis of the concentration distribution of Mg and hydrogen (H) in the thickness direction in p-type GaN doped with magnesium (Mg), which is a p-type impurity. ing. Note that FIG. 17A shows the results for GaN that has not been heat-treated after crystal growth, and FIG. 17B shows the results for GaN that has been heat-treated in a nitrogen atmosphere after crystal growth. In FIG. 17A, the H concentration is the same as that of Mg on the crystal surface and is the highest, decreases as it goes into the crystal, and is constant at about 1 × 10 ¹⁹ cm ⁻³ inside the crystal.

From this hydrogen (H) concentration distribution, a constant concentration of hydrogen (H) is taken into the group III nitride crystal during crystal growth, and further, hydrogen (H) in the atmospheric gas during the cooling process after the crystal growth is completed. It is considered that hydrogen penetrates and the hydrogen (H) concentration near the crystal surface increases. Further, the hydrogen (H) concentration in the region where the hydrogen (H) concentration is constant (the region indicated by reference numeral 3 in FIG. 1A) is about 1 × 10 ¹⁹ cm ⁻³ by heat treatment in a nitrogen atmosphere and is low. The resistance was the same as that showing the p-type. In FIG. 17B, the H concentration of the heat-treated GaN is 2 × 10 ¹⁹ cm ⁻³ (crystal surface) to 9 × 10 ¹⁸ cm ⁻³ (inside the crystal). From this, it is considered that the increase in resistance by hydrogen passivation occurs in the cooling process after the growth of the group III nitride crystal. That is, as shown in FIG. 2, it is considered that hydrogen is taken into the vicinity of the surface of the group III nitride crystal in the cooling process after the group III nitride crystal growth.

  Therefore, only the surface portion (the portion denoted by reference numeral 2 in FIG. 1A) is increased in resistance by hydrogen passivation, and the inside (the portion denoted by reference numeral 3 in FIG. 1A) is a low resistance p-type. By removing all or part of the crystal surface layer 2 having increased resistance (for example, by removing it as shown in FIG. 1B), a low resistance p as shown in FIG. A type III nitride semiconductor can be produced.

FIG. 3 is a diagram showing a specific example of the manufacturing process of the p-type group III nitride semiconductor according to the first embodiment. In the example of FIG. 3, a low-temperature GaN buffer layer 11 is deposited on the sapphire substrate 10 at 520 ° C., and then TMG (trimethylgallium) as a group III material is 10 ccm on the low-temperature GaN buffer layer 11, (EtCp) ₂ Mg as a p-type dopant is 100 ccm, NH ₃ as a nitrogen source is 5 LM, and a mixed gas of nitrogen gas 15 LM and hydrogen gas 6 LM is simultaneously flowed into the reaction tube, and the GaN layer 12 is grown at 1050 ° C. (FIG. 3A).

After crystal growth of the GaN layer 12, the supply of the group III material and the p-type dopant material was stopped, and the mixture was cooled to room temperature in a mixed gas atmosphere of NH ₃ gas 5LM, nitrogen gas 15LM, and hydrogen gas 6LM. At this time, when an electrode was formed on the surface of the GaN crystal 12 and the resistance was measured with a tester, the resistance was high and measurement was impossible.

  Next, when the hydrogen concentration in the thickness direction of the sample of FIG. 3A was measured by SIMS, the hydrogen concentration was highest on the surface on the GaN layer 12 side and gradually from the surface to a depth d of about 0.5 μm. The concentration was constant at a depth greater than that (FIG. 17 (a)).

A portion 13 having a depth d of about 0.5 μm was removed from the surface of the GaN crystal 12 by etching to manufacture the sample of FIG. When an electrode was formed on the sample of FIG. 3B and hole measurement was performed, the carrier concentration of the GaN layer 12 was 2 × 10 ¹⁷ cm ⁻³ , indicating a low resistance p-type.

  Thus, after growing a group III nitride crystal containing at least both a p-type impurity and hydrogen, all or part of the surface layer of the group III nitride crystal is removed to remove the p-type group III nitride semiconductor. Can produce a low-resistance p-type group III nitride semiconductor with little surface degradation.

Second Embodiment FIG. 4 is a diagram showing a second embodiment of a method for producing a group III nitride semiconductor according to the present invention. Referring to FIG. 4, in this method for manufacturing a group III nitride semiconductor, a predetermined layered structure 6 is formed on a group III nitride crystal 5 containing at least both p-type impurities and hydrogen. The nitride crystal 5 is manufactured as a p-type group III nitride semiconductor.

  Here, the predetermined laminated structure 6 can be formed by the following two methods.

  That is, in the second embodiment, the first method for manufacturing the predetermined laminated structure 6 is that the group III nitride crystal 5 containing at least both p-type impurities and hydrogen is grown immediately after the group III crystal growth. A predetermined laminated structure 6 is formed on the nitride crystal 5. Specifically, the group III nitride crystal 5 is grown, and subsequently (continuously), in the same crystal growth apparatus as the group III nitride crystal 5 is grown, the predetermined laminated structure 6 Is formed on the group III nitride crystal 5.

  According to this first method, the resistance of the p-type group III nitride can be reduced as follows. That is, as described above, the resistance of the p-type group III nitride is increased by diffusion of hydrogen from the surface of the group III nitride crystal into the group III nitride crystal in the cooling process after the completion of the group III nitride crystal growth. In the first method, the group III nitride crystal 5 containing at least both p-type impurities and hydrogen is grown on the group III nitride crystal 5 immediately after the crystal growth. As shown in FIG. 4, even if hydrogen (H) diffuses from the surface of the predetermined laminated structure 6 in the cooling process after the formation of the predetermined laminated structure 6, as shown in FIG. The diffusion of H) remains in the predetermined laminated structure 6 and does not reach the group III nitride crystal 5. That is, the hydrogen concentration in the group III nitride crystal 5 does not increase until the resistance of the group III nitride crystal 5 is increased.

  The predetermined laminated structure 6 can be formed of any one of single crystal, polycrystal, amorphous, and the like as long as it satisfies the function of keeping hydrogen diffusion in the laminated structure 6, and the structure is not limited. Absent. Further, the material of the predetermined laminated structure 6 is not particularly limited. For example, the predetermined laminated structure 6 can be a group III nitride laminated structure. Further, the electric conduction type of the predetermined laminated structure 6 is not particularly limited.

  In the first method, a predetermined stack that prevents diffusion and penetration of hydrogen from the atmospheric gas is not used by reducing the resistance by discharging hydrogen from the group III nitride 5 that has been increased in resistance by hydrogen passivation. By stacking the structure 6, high resistance of the low-resistance p-type group III nitride 5 is suppressed and a p-type group III nitride semiconductor is manufactured. It is different in principle. Therefore, there is no particular problem whether hydrogen is contained or not contained in the atmosphere gas during crystal growth and cooling.

FIG. 5 is a diagram showing a specific example of the manufacturing process of the p-type group III nitride semiconductor according to the first method of the second embodiment. Referring to FIG. 5, on a sapphire substrate 10 deposited at 520 ° C. and a low-temperature GaN buffer layer 21, TMG (trimethylgallium) is used as a group III material at 10 ccm, and (EtCp) ₂ Mg as a p-type dopant. Of GaN 22 was grown at 1050 ° C. by flowing NH ₃ as a nitrogen source into the reaction tube at the same time, and simultaneously flowing a mixed gas of nitrogen gas 15 LM and hydrogen gas 6 LM into the reaction tube (FIG. 5A).

Next, the supply of the p-type dopant was stopped, and GaN 23 not doped with impurities was grown as the group III nitride laminated structure 6 (FIG. 5B). After the growth of GaN 23, the supply of the group III raw material was stopped, and the mixture was cooled to room temperature in a mixed gas atmosphere of NH ₃ gas 5LM, nitrogen gas 15LM, and hydrogen gas 6LM.

Next, GaN 23 not doped with impurities was removed by etching (FIG. 5C), GaN 22 doped with magnesium was exposed, electrodes were formed on the surface thereof, and hole measurement was performed. As a result, the carrier concentration of GaN 22 was 2 × 10 ¹⁷ cm ⁻³ and showed a low resistance p-type.

  When the predetermined laminated structure 6 is subsequently laminated after the group III nitride crystal 5 is grown as in the first method, the laminated structure 6 is included in the atmospheric gas during the cooling process after the lamination. Since the hydrogen to be produced has a laminated structure 6, the cooling time from the lamination temperature to room temperature does not diffuse into the group III nitride crystal 5 as the resistance of the group III nitride crystal 5 increases, and the group III nitride The hydrogen concentration of the crystal does not increase. As a result, the group III nitride crystal 5 can have p-type conduction characteristics with low resistance.

  In the second embodiment, the second method for manufacturing the predetermined laminated structure 6 is that after the group III nitride crystal 5 containing at least both p-type impurities and hydrogen is grown and cooled, A predetermined laminated structure 6 is laminated. Specifically, for example, after the group III nitride crystal 5 containing at least both p-type impurities and hydrogen is grown, the group III nitride crystal 5 is taken out of the crystal growth apparatus, and after a certain process, The laminated structure 6 is laminated.

  According to the second method, the resistance of the p-type group III nitride can be reduced as follows. That is, when the laminated structure 6 is laminated after cooling the group III nitride crystal 5, as shown in FIG. 6, the hydrogen taken into the group III nitride crystal 5 during the lamination process of the laminated structure 6. (H) is released to the outside of the group III nitride crystal 5 (and released toward the laminated structure 6), and hydrogen to the group III nitride crystal 5 in the cooling process after the lamination of the laminated structure 6 is completed. Intrusion of (H) is prevented by the laminated structure 6, and the group III nitride crystal 5 can be manufactured as a p-type group III nitride semiconductor.

  In order to release hydrogen from the group III nitride crystal 5, it is desirable to laminate the laminated structure 6 at a temperature of 400 ° C. or higher.

  The predetermined laminated structure 6 can be formed of any one of single crystal, polycrystal, amorphous, and the like as long as it satisfies the function of keeping hydrogen diffusion in the laminated structure 6, and the structure is not limited. Absent. Further, the material of the predetermined laminated structure 6 is not particularly limited. For example, the predetermined laminated structure 6 can be a group III nitride laminated structure. Further, the electric conduction type of the predetermined laminated structure 6 is not particularly limited.

FIG. 7 is a diagram showing a specific example of the manufacturing process of the p-type group III nitride semiconductor according to the second method of the second embodiment. In the example of FIG. 7, a low temperature GaN buffer layer 31 is deposited on the sapphire substrate 10 at 520 ° C., and then, TMG (trimethylgallium) as a group III material is 10 ccm on the low temperature GaN buffer layer 31 and p (EtCp) ₂ Mg as a type dopant is 100 ccm, NH ₃ is 5 LM as a nitrogen source, and a mixed gas of nitrogen gas 15 LM and hydrogen gas 6 LM is simultaneously flowed into the reaction tube to grow a GaN layer 32 at 1050 ° C. (FIG. 7A).

After crystal growth of the GaN layer 32, the supply of the group III material and the p-type dopant material was stopped, and the mixture was cooled to room temperature in a mixed gas atmosphere of NH ₃ gas 5LM, nitrogen gas 15LM, and hydrogen gas 6LM. At this time, when an electrode was formed on the surface of the GaN crystal 32 and the resistance was measured with a tester, the resistance was high and measurement was impossible.

Next, the sample was put into another reactor, SiH ₄ and NH ₃ gas were flowed, and heated to 750 ° C., thereby depositing SiN 33 as a predetermined laminated structure (FIG. 7B). At this time, the GaN crystal 32 becomes a low-resistance p-type.

After depositing SiN33, SiN33 was removed by etching (FIG. 7C), an electrode was formed again on the GaN surface 32, and resistance measurement was performed. As a result, the carrier concentration of GaN 32 was 2 × 10 ¹⁷ cm ⁻³ , indicating a low resistance p-type.

  When the predetermined laminated structure 6 is laminated on the group III nitride crystal 5 whose resistance is increased by increasing the hydrogen concentration in the group III nitride crystal 5 as in the second method, the predetermined lamination During the stacking of the structure 6, hydrogen contained in the group III nitride crystal 5 is released to the outside, the resistance of the group III nitride crystal 5 is lowered, and cooling after the end of stacking of the predetermined layered structure 6 is performed. Diffusion penetration of hydrogen into the group III nitride crystal 5 from the atmosphere in the process is prevented by the predetermined laminated structure 6, and the group III nitride crystal 5 does not increase in resistance. As a result, the group III nitride crystal 5 can have p-type conduction characteristics with low resistance. In other words, in this second method, the p-type group III nitride is also obtained by laminating the predetermined laminated structure 6 that prevents the diffusion and penetration of hydrogen, instead of performing the heat treatment in an atmosphere containing substantially no hydrogen. Semiconductors can be manufactured. That is, in the second method, the atmosphere may contain hydrogen in particular.

  Furthermore, if this second method is used, after processing the group III nitride crystal 5, a group III nitride semiconductor multilayer structure having other characteristics is stacked, and the characteristics of the group III nitride semiconductor multilayer structure and the III It is also possible to manufacture a device using the characteristics of the group nitride crystal 5 as a p-type semiconductor without providing a special p-type treatment process.

  Thus, in the second embodiment, the predetermined laminated structure 6 can be formed by either the first method or the second method.

  Further, in the second embodiment, in any of the first method and the second method, the predetermined laminated structure (for example, a group III nitride laminated structure) 6 is a group III nitride containing at least Al. Can do.

  The group III nitride containing Al is easily etched with an alkaline solution. In addition, the etching rate differs depending on the crystallinity, and a single crystal with good crystallinity has the slowest etching rate. Therefore, the surface of the p-type group III nitride 5 can be easily etched by laminating a group III nitride containing single crystal, polycrystal, or amorphous Al having poor crystallinity as the predetermined laminated structure 6. Can be exposed.

  In the second embodiment, the thickness of the predetermined laminated structure (for example, a group III nitride laminated structure) 6 is preferably 0.5 μm or more.

  In the experiment by the inventor of the present application, as described above, the diffusion depth of hydrogen (H) is about 0.5 μm. Therefore, by increasing the thickness of the predetermined laminated structure 6 to 0.5 μm or higher, A low-resistance p-type group III nitride semiconductor with little influence of resistance can be manufactured.

Third Embodiment In the third embodiment of the present invention, when a p-type group III nitride semiconductor is manufactured, p containing at least p-type impurities in an atmosphere containing hydrogen gas as shown in FIG. The type III nitride semiconductor 7 is crystal-grown, and after crystal growth of the p-type group III nitride semiconductor 7, the temperature is lowered (cooled) in a gas atmosphere containing a nitrogen source as shown in FIG. 8B. Thus, the p-type group III nitride semiconductor 7 is manufactured.

Here, the gas atmosphere containing the nitrogen raw material (that is, the cooling atmosphere) is preferably an atmosphere containing monomethylhydrazine, dimethylhydrazine, other organic nitrogen compounds, or NH ₃ . More specifically, as a gas atmosphere containing a nitrogen source (that is, a cooling atmosphere), a mixed gas of an inert gas such as Ar and a nitrogen source, a mixed gas of nitrogen and a nitrogen source, or 100% nitrogen source gas Can be used. Further, a certain amount of hydrogen gas may be mixed with these gases.

The atomic nitrogen generated by the decomposition of the nitrogen source suppresses the decomposition of the group III nitride crystal surface, thereby reducing the surface defects that become the hydrogen diffusion path and suppressing the hydrogen diffusion and penetration. At the same time, since the increase in surface resistance due to the decomposition of the surface of the p-type group III nitride crystal is suppressed, it is expected that the group III nitride crystal will not increase in resistance. In fact, as a result of experiments by the inventors of the present application, the group III nitride (for example, GaN) exhibited p-type characteristics with as grown and low resistance by using NH ₃ gas as the cooling atmosphere.

The gas atmosphere containing nitrogen material (i.e., cooling atmosphere) as, for example, can be a mixed gas of NH ₃ gas and nitrogen gas, the atomic nitrogen produced by the decomposition of the NH ₃ gas III From the viewpoint of suppressing the decomposition of the group nitride crystal surface, it is preferable that the proportion of NH ₃ gas in the mixed gas is large. If the ratio is not 0%, the effect can be expected, but preferably 25% or more, more preferably 50 to 100%.

  Similarly, in the case of other organic nitrogen raw materials, it is better that the ratio of nitrogen raw materials is large.

  From the above, the p-type group III nitride can be produced as grown by setting the cooling atmosphere after the group III nitride crystal growth to a gas containing at least a nitrogen raw material.

More specifically, in the experiment by the inventors of the present application, in NH ₃ gas 100%, or a mixed gas of NH ₃ gas and nitrogen gas (when NH ₃ is 25% and NH ₃ is 60%) ) Or in a mixed gas of NH ₃ gas, nitrogen gas and hydrogen gas (6% hydrogen), and in each case as grown, low resistance having a carrier concentration of 2 × 10 ¹⁷ cm ⁻³ Of p-type group III nitrides could be produced.

  In addition, when hydrogen is contained in the atmospheric gas during cooling, the cleaning effect by hydrogen of unreacted organic raw materials and organic substances adsorbed on the crystal surface can be expected, thus preventing an increase in surface resistance due to surface contamination. it can. This is an effect that cannot be obtained by the prior art.

The nitrogen raw material is not particularly limited, but by using a compound that generates hydrogen by its decomposition, such as NH ₃ , the effect of suppressing the decomposition of the crystal surface by atomic nitrogen (thereby suppressing the diffusion of hydrogen) Effect) and a cleaning effect by hydrogen can be obtained at the same time.

In the prior art 1 described above, in an atmosphere containing a compound that generates hydrogen (such as NH ₃ ) or hydrogen gas, it is difficult to discharge the hydrogen from the high-resistance group III nitride to make it p-type. The heat treatment was performed in an atmosphere containing substantially no hydrogen. In contrast, the present invention suppresses the diffusion and penetration of hydrogen into the low-resistance p-type group III nitride immediately after crystal growth, thereby preventing high resistance in the cooling process after crystal growth and reducing the resistance. A p-type group III nitride semiconductor is manufactured. Therefore, it is different in principle from the prior art. The atmosphere may contain a compound that generates hydrogen (such as NH ₃ ) or a certain amount of hydrogen gas. And when it contains hydrogen, the point which utilizes the effect of hydrogen actively also differs from a prior art.

  Next, a specific example of the manufacturing process of the third embodiment will be described. In this specific example, p-type GaN was grown as a p-type group III nitride semiconductor by MOCVD.

  First, the sapphire substrate was set in an MOCVD apparatus and heated in hydrogen gas at 1120 ° C. to clean the substrate surface.

Next, the temperature was lowered to 520 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen, and hydrogen, TMG (trimethylgallium) was flowed at 20 ccm using hydrogen as a carrier gas, and a low-temperature GaN buffer layer was deposited.

Next, the temperature is raised to 1050 ° C., 10 ccm of TMG (trimethylgallium), 100 ccm of (EtCp) ₂ Mg as a p-type dopant, 5 LM of NH ₃ as a nitrogen source, 15 LM of nitrogen gas and 6 LM of hydrogen gas And GaN were crystal-grown at 1050 ° C.

After the GaN crystal growth, the supply of group III material, p-type dopant material and hydrogen gas was stopped, and the mixture was cooled to room temperature in a mixed gas atmosphere of ammonia (NH ₃ ) gas 5LM and nitrogen gas 15LM. The nitrogen gas 15LM flows as a confining gas for actively blowing ammonia (NH ₃ ) to the substrate surface, and the atmosphere on the substrate surface is mostly ammonia (NH ₃ ) gas.

Next, an electrode was formed on the surface of the GaN crystal, and hole measurement was performed. As a result, the carrier concentration of the GaN layer was 2 × 10 ¹⁷ cm ⁻³ , indicating a low resistance p-type.

In addition, after GaN crystal growth was performed by the same growth method, a GaN crystal was manufactured that was cooled from the growth temperature to room temperature in an atmosphere of 100% ammonia (NH ₃ ) gas. As a result of forming an electrode on the surface of the GaN crystal and performing hole measurement, the carrier concentration was 2 × 10 ¹⁷ cm ⁻³ and a low resistance p-type was shown.

  Next, another specific example of the manufacturing process of the third embodiment will be described. In this specific example (manufacturing process example), p-type GaN was grown as a p-type group III nitride semiconductor on n-type GaN by MOCVD to produce a pn junction diode as shown in FIG.

In this example of the manufacturing process, first, the sapphire substrate 110 was set in an MOCVD apparatus and heated at 120 ° C. in hydrogen gas to clean the surface of the substrate 110. Next, the temperature was lowered to 520 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen, and hydrogen, TMG (trimethylgallium) was flowed at 20 ccm using hydrogen as a carrier gas, and a low-temperature GaN buffer layer 111 was deposited.

Next, the temperature is raised to 1050 ° C., TMG (trimethylgallium) is 10 ccm, SiH ₄ is 5.5 ccm as an n-type dopant, NH ₃ is 5 LM as a nitrogen source, nitrogen gas 15 LM and hydrogen gas 6 LM The n-type GaN layer 112 was grown at a temperature of 1050 ° C. at a temperature of 1050 ° C.

Subsequently, 10 ccm of TMG (trimethylgallium), 100 ccm of (EtCp) ₂ Mg as a p-type dopant, 5 LM of NH ₃ as a nitrogen source, and a mixed gas of nitrogen gas 15 LM and hydrogen gas 6 LM at the same time The p-type GaN layer 113 was grown to a thickness of 0.5 μm at 1050 ° C. through a reaction tube.

After the crystal growth of the p-type GaN layer 113, the supply of the group III material, the p-type dopant material, the hydrogen gas, and the nitrogen gas was stopped, and the mixture was cooled to room temperature in an atmosphere of ammonia (NH ₃ ) gas 5LM. Next, dry etching was performed to remove a part of the p-type GaN layer 113 to expose the n-type GaN layer 112.

  Next, indium was attached to the surfaces of the p-type GaN layer 113 and the n-type GaN layer 112, respectively, and heated to 200 ° C. to form the p-side and n-side electrodes 114 and 115. The reason why indium was used for the electrode is to avoid annealing at a high temperature (400 ° C. or higher) when forming the electrode in order to distinguish it from the effect of the manufacturing method of p-type GaN described in the prior art 1. .

  Next, a voltage was applied to the p-side and n-side electrodes 114 and 115 in the forward or reverse direction, and the current-voltage characteristics were examined. FIG. 19 is a diagram showing current-voltage characteristics when a voltage is applied to the p-side and n-side electrodes 114 and 115. From FIG. 19, in the manufactured pn junction, current hardly flowed when voltage was applied in the reverse direction, and current flowed when voltage was applied in the forward direction. That is, rectification characteristics are shown, and it can be seen that a diode is formed.

  From this, it can be seen that p-type GaN is manufactured in as grown and a pn junction is formed.

Fourth Embodiment In a fourth embodiment of the present invention, in the method for manufacturing a p-type group III nitride semiconductor of the second embodiment described above, the outermost surface layer of the predetermined stacked structure 6 contains hydrogen gas. It is formed of a layer that can be grown in a non-atmosphere. Specifically, the outermost surface layer of the predetermined laminated structure 6 is a group III nitride containing at least In, and the group III nitride containing at least In is in an atmosphere not containing hydrogen gas or against hydrogen gas. Crystal growth is performed in an atmosphere in which nitrogen source gas and nitrogen gas are excessive, and cooling is performed in a gas atmosphere containing at least a nitrogen source after completion of crystal growth of a group III nitride containing at least In.

  A p-type group III nitride crystal having a lower resistance than that of the p-type group III nitride semiconductor obtained by the method for manufacturing a p-type group III nitride semiconductor of the first, second, and third embodiments described above is manufactured. For this purpose, it is necessary not to incorporate hydrogen into the group III nitride crystal, which deactivates the acceptor and makes it highly resistant.

  For this purpose, the inventors of the present application tried to grow a group III nitride crystal in an atmosphere containing no hydrogen. However, when a group III nitride such as GaN or AlGaN was crystal-grown in an atmosphere containing no hydrogen, the surface irregularities became severe and high quality crystals could not be obtained.

On the other hand, the group III nitride crystal containing In is reduced as much as possible to grow hydrogen in an atmosphere of nitrogen source and nitrogen gas excess, and after the growth of the group III nitride crystal is completed, in order to prevent decomposition of the crystal surface, At least at high temperatures, the nitrogen source (generally ammonia NH ₃ ) and nitrogen gas are not stopped, and the temperature is lowered to room temperature in an atmosphere with a high nitrogen partial pressure. I was able to.

  Therefore, for a group III nitride not containing In, a group III nitride containing high quality In in an atmosphere containing as little hydrogen as possible on the outermost surface of the laminated structure 6 is grown in a high quality crystal in an atmosphere containing hydrogen. As a result, it was possible to manufacture a high-quality, low-resistance p-type group III nitride semiconductor.

  According to the method of the fourth embodiment, the hydrogen taken into the group III nitride crystal 5 during the growth of the group III nitride crystal 5 is a group III containing In in an atmosphere containing almost no hydrogen. During the growth of the nitride crystal, it is efficiently released out of the group III nitride crystal 5, so that the hydrogen concentration in the group III nitride crystal 5 is lowered and the resistance is further reduced. Further, since the diffusion and penetration of hydrogen during cooling is prevented, the group III nitride crystal 5 is not increased in resistance, and an as-grown and low resistance p-type group III nitride semiconductor can be manufactured.

Fifth Embodiment In the fifth embodiment of the present invention, when a p-type group III nitride semiconductor is manufactured, as shown in FIG. 9, both a p-type impurity and hydrogen grown in an atmosphere containing hydrogen are used. Group III nitride containing at least p-type impurities and In in an atmosphere not containing hydrogen gas or an atmosphere in which nitrogen source gas and nitrogen gas are excessive with respect to hydrogen gas on group III nitride crystal 5 containing at least The product (group III nitride multilayer structure) 8 is crystal-grown, and after the crystal growth of the group III nitride (group III nitride multilayer structure) 8 is completed, cooling is performed in a gas atmosphere containing at least a nitrogen raw material, whereby p-type III A group nitride semiconductor 5 and a p-type group III nitride (p-type group III nitride laminated structure) 8 are manufactured.

  That is, when a group III nitride containing no In is grown in an atmosphere containing no hydrogen, it is difficult to produce a crystal with good crystallinity due to severe surface irregularities. On the other hand, a group III nitride containing In can be produced with good crystallinity even if crystal growth is performed in an atmosphere not containing hydrogen. Therefore, by growing a group III nitride 8 containing In in an atmosphere containing almost no hydrogen, a crystal (group III nitride containing In) 8 having good crystallinity and less hydrogen uptake during crystal growth. Can be manufactured.

  Further, in the method for growing a group III nitride 8 containing In according to the fifth embodiment, the group III nitride 8 containing In grows in an atmosphere containing as little hydrogen as possible. Therefore, the group III nitride crystal 5 The hydrogen taken in during the crystal growth is released out of the group III nitride crystal 5 during the growth of the group III nitride crystal 8 containing In. That is, since the group III nitride 8 grows on the group III nitride 5, the hydrogen taken into the group III nitride crystal 5 during the growth of the group III nitride 8 is group III nitride. A large amount is released out of the material crystal 5, and as a result, the resistance of the group III nitride crystal 5 is lowered.

  Further, in the group III nitride 8 containing In, since the atmosphere during crystal growth of the group III nitride 8 is an atmosphere that does not contain hydrogen as much as possible, there is little inactivation of the acceptor by hydrogen, and high in this atmosphere. Since quality crystals can be grown, there is little compensation for acceptors due to donor defects. Furthermore, the group III nitride 8 containing In, such as InGaN, has a narrower band gap than GaN or the like and is likely to be p-type.

  In the cooling process, since the atmosphere is a gas atmosphere containing at least a nitrogen raw material, the same effect as in the third embodiment can be obtained. That is, in the cooling process, since the atmospheric gas is a gas atmosphere containing at least a nitrogen raw material, degradation due to decomposition of the crystal surface of the group III nitride 8 is prevented, resistance to high resistance due to defects is prevented, and in the atmosphere High resistance due to diffusion and penetration of hydrogen from is suppressed, and a group III nitride crystal (for example, InGaN crystal) 8 containing In showing p type as grown with low resistance is obtained. That is, as a group III nitride crystal 8 containing In, an InGaN crystal exhibiting an as-grown and low resistance p-type can be obtained without post-processing for p-type conversion. As a result, the group III nitride semiconductor 5 becomes a p-type group III nitride semiconductor with further lower resistance, and the group III nitride 8 also becomes a low-resistance p-type group III nitride semiconductor with good crystallinity. Can do. That is, both the group III nitride 5 and the group III nitride (group III nitride laminated structure) 8 can grow as a p-type semiconductor with low resistance.

  In addition, in the manufacturing method of the p-type group III nitride semiconductor of the first, second, third, fourth, and fifth embodiments described above, the p-type impurity is changed to Mg so that the resistance is low even at room temperature. A p-type group III nitride semiconductor can be manufactured.

  That is, since the impurity level of Mg is lower than other impurity levels such as Zn, the activation rate is higher than other impurities and it is easy to obtain a p-type group III nitride having a lower resistance. For example, the impurity level of Mg in GaN is the lowest among the p-type impurities of about 200 meV and other group III elements above the valence band of GaN, and is activated even at room temperature. Therefore, a low-resistance p-type group III nitride semiconductor can be manufactured even at room temperature.

  In addition, the present invention can provide the group III nitride semiconductor manufactured in the first, second, third, fourth, or fifth embodiment. That is, it is possible to provide a p-type group III nitride semiconductor with little surface degradation and low resistance.

  According to the present invention, in the semiconductor device having at least a p-type semiconductor layer, the p-type semiconductor layer includes a group III nitride manufactured in the first, second, third, fourth, or fifth embodiment. A physical semiconductor can be used. Specifically, the semiconductor device having the p-type group III nitride semiconductor 3 or 7 manufactured by the method for manufacturing the p-type group III nitride semiconductor of the first or third embodiment described above, or the above-mentioned A semiconductor device having a stacked structure including the p-type group III nitride semiconductor 5 manufactured by the method for manufacturing a p-type group III nitride semiconductor of the second, fourth, or fifth embodiment, or the above-mentioned The p-type group III nitride semiconductor 5 manufactured by the method for manufacturing a p-type group III nitride semiconductor of the second, fourth, or fifth embodiment and all or part of the stacked structure 6 or 8 are included. A semiconductor device can be provided.

  This semiconductor device can be configured as a light emitting element, a light receiving element, an electronic device, or the like.

  FIG. 10 is a diagram illustrating an example of a semiconductor device according to the present invention. In the example of FIG. 10, the semiconductor device is configured as a photodiode. In the manufacturing process of the photodiode of FIG. 10, a p-type group III nitride (a p-type GaN layer 44 and a p-type GaN contact layer 45 described later) is manufactured by the method according to the second embodiment.

  Referring to FIG. 10, this photodiode is formed by sequentially laminating a low-temperature GaN buffer layer 41, a high-temperature GaN buffer layer 42, an n-type GaN layer 43, a p-type GaN layer 44, and a p-type GaN contact layer 45 on a sapphire substrate 40. A mesa structure having a diameter of 150 μm is formed by etching the laminated structure until the n-type GaN layer 43 is exposed.

  A ring-shaped p-side ohmic electrode 47 is formed on the top of the mesa structure, and an n-side ohmic electrode 48 is formed on the exposed n-type GaN layer 43.

  A SiN insulating protective film 46 is formed in a region other than the portion where the ohmic electrodes 47 and 48 are formed. A wiring electrode 49 is formed on the side surface of the mesa structure and on the SiN insulating protective film 46 on the n-type GaN 43 so as to be drawn from the p-side ohmic electrode 47.

  In this photodiode, the portion surrounded by the ring-shaped p-side ohmic electrode 47 at the top of the mesa structure is the light receiving surface. When a reverse bias is applied to the photodiode and the light receiving surface is irradiated with light (hν), a photocurrent corresponding to the intensity of the light flows.

  Next, a method for manufacturing the photodiode of FIG. 10 will be described. First, the sapphire substrate 40 was set in a reaction tube and heated at 1120 ° C. in hydrogen gas to clean the surface of the substrate 40.

Next, the temperature was lowered to 520 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ gas 5LM, nitrogen gas 15LM, and hydrogen gas 6LM, TMG was allowed to flow, and the low temperature GaN buffer layer 41 was deposited.

Next, the temperature was raised to 1050 ° C., TMG was supplied using hydrogen as a carrier gas, a high-temperature GaN buffer layer 42 was laminated by 2 μm, and SiH ₄ was added, followed by laminating an n-type GaN layer 43 by 3 μm.

Next, the supply of SiH ₄ was stopped, (EtCp) ₂ Mg was supplied, the p-type GaN layer 44 was laminated by 1 μm, and then the p-type GaN contact layer 45 was laminated by 0.2 μm. Thereafter, the supply of TMG and (EtCp) ₂ Mg was stopped, the mixture was cooled to room temperature in a mixed gas atmosphere of NH ₃ gas 5LM, nitrogen gas 15LM and hydrogen gas 6LM, and the wafer was taken out from the reaction tube. When the electrical continuity was examined by applying a tester to the wafer surface, the resistance was high and there was no continuity.

  Next, a circular pattern having a diameter of 150 μm was formed from a resist. Using this resist pattern as a mask, dry etching was performed to form a mesa shape having a height of about 2 μm, and the n-type GaN layer 43 was exposed.

After removing the resist mask, the wafer was set in another reaction tube, SiH ₄ and NH ₃ gas were flowed and heated to 750 ° C., and about 0.5 μm of SiN 46 was deposited on the surface. At this time, the group III nitride (p-type GaN layer 44, p-type GaN contact layer 45) containing the p-type impurity becomes a low-resistance p-type group III nitride semiconductor.

  Next, a p-side ohmic electrode 47 was formed. The process of forming the P-side ohmic electrode 47 is as follows.

  That is, first, a ring-shaped pattern is formed with a resist on the top of the mesa structure, and then SiN 46 is etched into a ring shape to expose the p-type GaN contact layer 45.

  Next, Ni / Au as a p-side ohmic electrode material was deposited. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form a p-side ohmic electrode pattern on the mesa structure. Thereafter, heat treatment was performed at 600 ° C. in a nitrogen atmosphere to form a p-side ohmic electrode 47 on the p-type GaN contact layer 45.

  Next, an n-side ohmic electrode 48 and a wiring electrode 49 were formed. The formation process of the n-side ohmic electrode 48 and the wiring electrode 49 is as follows.

  First, on the SiN film 46 on the n-type GaN layer 43, a nuki pattern having a shape surrounding the mesa structure is formed with a resist, and then the SiN film 46 is etched to expose the n-type GaN layer 43.

  Next, the resist is removed, and a lift-off pattern of the wiring electrode and the n-side ohmic electrode is formed again with the resist.

  Subsequently, Ti / Al which is an n-side ohmic electrode and a wiring electrode material was vapor-deposited. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form an n-side ohmic electrode 48 and a wiring electrode 49 pattern. Thereafter, the n-side ohmic electrode 48 was formed by heat treatment at 450 ° C. in a nitrogen atmosphere.

  As a result of investigating the photodiode of FIG. 10, the photodiode of FIG. 10 has almost no decomposition of the crystal surface due to the heat treatment for p-type conversion as in the prior art 1 or the prior art 3, so that no crystal defects occur, It became a photodiode with little dark current.

  Further, in the present invention, the p-type group III nitride semiconductor 5 and the p-type group III nitride semiconductor (p-type group III nitride stacked layer) manufactured by the method for manufacturing a p-type group III nitride semiconductor of the fifth embodiment are used. Structure) a semiconductor device having all or part of 8 and having a p-side ohmic electrode formed on the surface of the p-type group III nitride semiconductor 8 (p-type group III nitride manufactured by the method of the fifth embodiment) (Semiconductor device including all or a part of the p-type group III nitride 8 including at least In and the p-type group III nitride 8 including at least In and the p-type ohmic electrode) it can.

  This semiconductor device can be configured as a light emitting element, a light receiving element, an electronic device, or the like.

11 and 12 show a p-type group III nitride semiconductor manufactured by the methods of the fourth and fifth embodiments as a p-type semiconductor layer (a p-type Al _0.07 Ga _0.93 N clad layer 55, a p-type GaN cap described later). 13 is a diagram showing an example of a semiconductor device used for the layer 56 and the p-type In _0.1 Ga _0.9 N contact layer 57). The semiconductor device in the example of FIGS. 11 and 12 includes an edge-emitting light emitting diode and an edge-receiving photodiode. Is configured as a light receiving and emitting element monolithically integrated. 11 is a cross-sectional view taken along a plane perpendicular to the light emitting end face of the light emitting diode of the light emitting / receiving element, and FIG. 12 is a cross sectional view taken along a plane parallel to the light emitting end face of the light emitting diode.

11 and 12, the light emitting diode and the photodiode have a substantially rectangular parallelepiped shape, and a space is provided so that one light emitting end face of the light emitting diode faces the light receiving end face of the photodiode. Are separated from each other. The light emitting diode and the photodiode have the same laminated structure. This laminated structure includes an AlN low-temperature buffer layer 51, an n-type Al _0.03 Ga _0.97 N contact layer 52, an n-type Al _0.07 Ga _0.93 N cladding layer 53, an In _0.17 Ga _0.83 N active layer 54, a p-type on a sapphire substrate 50. An Al _0.07 Ga _0.93 N cladding layer 55, a p-type GaN cap layer 56, and a p-type In _0.1 Ga _0.9 N contact layer 57 are sequentially laminated.

In the light emitting diode and the photodiode, the stacked structure is etched from the surface of the p-type In _0.1 Ga _0.9 N contact layer 57 to the n-type Al _0.03 Ga _0.97 N contact layer 52, and the n-type Al _0.03 Ga _0.97 N contact layer 52 is etched. The surface is exposed. A p-side ohmic electrode 59 made of Ni / Au is formed on the p-type In _0.1 Ga _0.9 N contact layer 57 of the light emitting diode and the photodiode.

An n-side ohmic electrode 60 made of Ti / Al is formed on the exposed n-type Al _0.03 Ga _0.97 N contact layer 52.

Further, an insulating protective film 58 made of SiO ₂ is deposited on portions other than the ohmic electrodes 59 and 60. A wiring electrode 61 made of Ti / Al is formed on the insulating protective film 58. The wiring electrode 61 is electrically connected to the p-side ohmic electrode 59 of each of the light emitting diode and the photodiode.

  The side surfaces of the light emitting diode and the photodiode are formed substantially perpendicular to the substrate. The side surfaces that face each other through the groove 62 of the light emitting diode and the photodiode become a light emitting end surface and a light receiving surface, respectively. Further, the end surface of the light emitting diode opposite to the end surface facing the photodiode is a light emitting end surface that emits light to the outside.

  This integrated light emitting / receiving element operates by injecting a forward current into the light emitting diode and applying a reverse bias to the photodiode. That is, when a bias is applied in the forward direction or the reverse direction to the p-side ohmic electrode 59 and the n-side ohmic electrode 60 of each element, the light emitting diode emits light from two light emitting end faces. Then, the light emitted from the light emitting end face directed to the photodiode is incident on the light receiving surface of the photodiode, and a photoelectromotive force corresponding to the intensity is generated in the photodiode and taken out as a photocurrent to the outside. By monitoring the photocurrent of the photodiode, the current injected into the light emitting diode can be adjusted to control the light output.

  Next, a method for manufacturing the integrated light emitting and receiving element shown in FIGS. 11 and 12 will be described. The laminated structure of the integrated light emitting / receiving element was manufactured by crystal growth by MOCVD.

  First, the sapphire substrate 50 was set in a reaction tube and heated at 1120 ° C. in hydrogen gas to clean the substrate surface.

Next, the temperature was lowered to 520 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, TMA was flown, and a low temperature AlN buffer layer 51 was deposited.

Next, the temperature is raised to 1050 ° C., TMG, TMA, and SiH ₄ are supplied in accordance with the composition using hydrogen as a carrier gas, and an n-type Al _0.03 Ga _0.97 N contact layer 52 is laminated by 3 μm to form an n-type Al _0.07 Ga _0.93. The N clad layer 53 was laminated by 0.5 μm.

Next, the supply of hydrogen gas is stopped, the atmosphere is changed to a mixed gas atmosphere of NH ₃ and nitrogen, the temperature is lowered to 810 ° C., TMG and TMI are supplied using hydrogen as a carrier gas, and the In _0.17 Ga _0.83 N active layer 54 Was grown to 50 nm.

Next, the atmosphere is changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, the temperature is raised to 1050 ° C., hydrogen is used as a carrier gas, TMG, TMA, (EtCp) ₂ Mg are supplied according to the composition, and p-type Al _{A 0.07} Ga _0.93 N clad layer 55 was laminated by 0.5 μm, and a p-type GaN cap layer 56 was laminated by 0.2 μm.

Next, the supply of hydrogen gas is stopped, the atmosphere is changed to a mixed gas atmosphere of NH ₃ and nitrogen, the temperature is lowered to 810 ° C., TMG, TMI, (EtCp) ₂ Mg is supplied using hydrogen as a carrier gas, and p-type An In _0.1 Ga _0.9 N contact layer 57 was laminated to a thickness of 0.1 μm. After the growth was completed, the supply of TMG, TMI, (EtCp) ₂ Mg was stopped, and the mixture was cooled to room temperature in a mixed gas atmosphere of NH ₃ and nitrogen (NH ₃ and nitrogen supply ratio was 3: 2). When a tester was applied to the growth surface, there was conduction, and it was confirmed that the uppermost In _0.1 Ga _0.9 N contact layer 57 was a low-resistance p-type semiconductor.

Next, a pattern in which two rectangular patterns with a width of 30 μm and a length of 50 μm were arranged 5 μm apart in the length direction was formed with a resist. Using this resist pattern as a mask, dry etching was performed to form a rectangular parallelepiped shape with a height of about 1.5 μm to be a light emitting diode and a photodiode, and the n-type Al _0.03 Ga _0.97 N contact layer 52 was exposed.

Next, about 0.5 μm of SiO _{2 serving} as the insulating protective film 58 was deposited on the surface of the laminated structure. Next, a p-side ohmic electrode 59 was formed.

The formation process of the P-side ohmic electrode 59 is as follows. That is, first, after forming a stripe pattern with resist on the light emitting diode and the photodiode, the SiO ₂ film 58 is etched to expose the p-type In _0.1 Ga _0.9 N contact layer 57 on the ridge.

Next, Ni / Au as a p-side ohmic electrode material was deposited. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form a p-side ohmic electrode pattern on the light emitting diode and the photodiode. Thereafter, heat treatment was performed at 600 ° C. in a nitrogen atmosphere to form a p-side ohmic electrode 59 on the p-type In _0.1 Ga _0.9 N contact layer 57.

Next, an n-side ohmic electrode 60 and a wiring electrode 61 were formed. The formation process of the n-side ohmic electrode 60 and the wiring electrode 61 is as follows. First, on n-type Al _0.03 Ga _0.97 N contact layer 52 upper part of the SiO ₂ film 58, after forming the Nuqui stripe pattern of about 100μm width resist, the n-type a SiO ₂ film 58 is etched Al _0.03 Ga _0.97 N The contact layer 52 is exposed.

  Next, the resist is removed, and a lift-off pattern of the wiring electrode 61 and the n-side ohmic electrode 60 is formed again with the resist. Subsequently, Ti / Al which is an n-side ohmic electrode and a wiring electrode material was vapor-deposited. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form an n-side ohmic electrode and a wiring electrode pattern. Thereafter, the n-side ohmic electrode 60 was formed by heat treatment at 450 ° C. in a nitrogen atmosphere. Next, dicing was performed to separate the integrated light emitting / receiving element into chips.

  In the integrated light emitting / receiving element manufactured as described above, when a current was injected into the light emitting diode to emit light, the peak wavelength of light emission was about 412 nm.

13 shows a p-type group III nitride semiconductor manufactured by the methods of the fourth and fifth embodiments as a p-type semiconductor layer (a p-type Al _0.2 Ga _0.8 N layer 76 and a p-type GaN guide layer 77 described later). , P-type Al _0.12 Ga _0.88 N clad layer 78, p-type GaN cap layer 79, p-type In _0.1 Ga _0.9 N contact layer 80), showing another example of the semiconductor device shown in FIG. The semiconductor device is configured as a semiconductor laser. FIG. 13 is a cross-sectional view taken along a plane perpendicular to the light emitting direction of the semiconductor laser.

Referring to FIG. 13, this semiconductor laser includes an AlGaN low temperature buffer layer 71, an n-type Al _0.03 Ga _0.97 N contact layer 72, an n-type Al _0.12 Ga _0.88 N cladding layer 73, an n-type GaN guide layer on a sapphire substrate 70. 74, In _0.15 Ga _0.85 N / In _0.02 Ga _0.98 N multiple quantum well active layer 75, p-type Al _0.2 Ga _0.8 N layer 76, p-type GaN guide layer 77, p-type Al _0.12 Ga _0.88 N cladding layer 78, p-type A GaN cap layer 79 and a p-type In _0.1 Ga _0.9 N contact layer 80 are sequentially stacked.

Etching from the surface of the p-type In _0.1 Ga _0.9 N contact layer 80 to the n-type Al _0.03 Ga _0.97 N contact layer 72 exposes the surface of the n-type Al _0.03 Ga _0.97 N contact layer 72. An n-side ohmic electrode 83 made of Ti / Al is formed on the exposed n-type Al _0.03 Ga _0.97 N contact layer 72.

Further, the current confinement ridge structure 800 is formed by etching from the surface of the p-type In _0.1 Ga _0.9 N contact layer 80 to the middle of the p-type Al _0.12 Ga _0.88 N cladding layer 78. A p-side ohmic electrode 82 made of Ni / Au is formed on the p-type In _0.1 Ga _0.9 N contact layer 80 on the outermost surface of the ridge structure 800.

Further, except for the electrode forming portion, SiO ₂ is deposited as the insulating protective film 81. An optical resonator end face is formed substantially perpendicular to the laminated structure and the current confinement ridge structure 800.

  Next, a method for manufacturing the semiconductor laser of FIG. 13 will be described. The crystal growth of the stacked structure of the semiconductor laser was performed by the MOCVD method.

  First, the sapphire substrate 70 was set in a reaction tube and heated at 1120 ° C. in hydrogen gas to clean the surface of the substrate 70.

Next, the temperature was lowered to 520 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen, and hydrogen, TMG and TMA were flowed, and a low temperature AlGaN buffer layer 71 was deposited.

Next, the temperature is raised to 1050 ° C., TMG, TMI, and SiH ₄ are supplied in accordance with the composition using hydrogen as a carrier gas. The n-type Al _0.03 Ga _0.97 N contact layer 72 is 2 μm, and the n-type Al _0.12 Ga _0.88 N clad The layer 73 was laminated by 0.7 μm, and the n-type GaN guide layer 74 was laminated by 0.1 μm.

Next, the supply of hydrogen gas is stopped, the atmosphere is changed to a mixed gas atmosphere of NH ₃ and nitrogen, the temperature is lowered to 810 ° C., TMG and TMI are supplied using hydrogen as a carrier gas, and In _0.15 Ga _0.85 N / In _0.02 A Ga _0.98 N multiple quantum well active layer 75 (2 pairs) was grown.

Next, the atmosphere is changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, the temperature is raised to 1050 ° C., hydrogen is used as a carrier gas, TMG, TMA, (EtCp) ₂ Mg are supplied according to the composition, and p-type Al _{The 0.2} Ga _0.8 N layer 76 was stacked to 20 nm, the p-type GaN guide layer 77 to 0.1 μm, the p-type Al _0.12 Ga _0.88 N cladding layer 78 to 0.7 μm, and the p-type GaN cap layer 79 to 0.2 μm.

Next, the supply of hydrogen gas is stopped, the atmosphere is changed to a mixed gas atmosphere of NH ₃ and nitrogen, the temperature is lowered to 810 ° C., TMG, TMI, (EtCp) ₂ Mg is supplied using hydrogen as a carrier gas, and p-type An In _0.1 Ga _0.9 N contact layer 80 was laminated to a thickness of 0.1 μm.

After the growth of the p-type In _0.1 Ga _0.9 N contact layer 80, the supply of TMG, TMI, (EtCp) ₂ Mg was stopped, and the mixture was cooled to room temperature in an atmosphere of NH ₃ gas 100%.

At this time, when a tester is applied to the surface of the p-type In _0.1 Ga _0.9 N contact layer 80, conduction is confirmed, and it is confirmed that the uppermost In _0.1 Ga _0.9 N contact layer 80 is a low-resistance p-type semiconductor. It was.

  Next, a stripe pattern having a width of 4 μm was repeatedly formed with a resist at a pitch of 1 mm using a resist, and dry etching was performed to a depth of about 0.7 μm using the resist pattern as a mask to form a ridge structure 800.

Next, the resist mask was removed, and then a stripe pattern having a width of 500 μm covering the ridge structure 800 with a resist was repeatedly formed at a pitch of 1 mm. Using this resist pattern as a mask, the n-type Al _0.03 Ga _0.97 N contact layer 72 was exposed by dry etching of about 1.5 μm.

Next, about 0.5 μm of SiO _{2 serving} as the insulating protective film 81 was deposited on the surface of the laminated structure.

Next, a p-side ohmic electrode 82 was formed. The formation process of the P-side ohmic electrode 82 is as follows. First, after forming a stripe pattern on the ridge structure 800 with a resist, the SiO ₂ film 81 was etched to expose the p-type In _0.1 Ga _0.9 N contact layer 80 on the ridge structure 800.

Next, the resist was removed, and a resist stripe pattern having a width of about 450 μm was formed again. Ni / Au as a p-side ohmic electrode material was deposited on the ridge structure 800. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form a p-side ohmic electrode pattern only on the semiconductor laser laminated structure. Thereafter, heat treatment was performed at 600 ° C. in a nitrogen atmosphere to form a p-side ohmic electrode 82 on the p-type In _0.1 Ga _0.9 N contact layer 80.

Next, an n-side ohmic electrode 83 was formed. The formation process of the n-side ohmic electrode 83 is as follows. First, on the SiO ₂ film 81 on the n-type Al _0.03 Ga _0.97 N contact layer 72, a resist stripe pattern having a width of about 100 μm is formed with a resist, and then the SiO ₂ film 81 is etched to form an n-type Al _0.03 Ga _0.97 N. The contact layer 72 was exposed.

  In this state, Ti / Al, which is an n-side ohmic electrode material, was deposited. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form an n-side ohmic electrode pattern. Thereafter, the n-side ohmic electrode 83 was formed by heat treatment at 450 ° C. in a nitrogen atmosphere.

  Next, the sapphire substrate 70 was thinly polished and divided so as to be substantially perpendicular to the ridge structure 800 to form an optical resonator end face.

  When a forward current was injected into the electrodes 82 and 83, light was emitted, and when the current was further increased, laser oscillation occurred. The oscillation wavelength was about 409 nm.

14 shows a p-type group III nitride semiconductor manufactured by the second method of the second embodiment as a p-type semiconductor layer (a p-type Al _0.2 Ga _0.8 N layer 96, a p-type GaN guide layer 97 described later). , P-type Al _0.12 Ga _0.88 N clad layer 98, p-type GaN contact layer 99). FIG. 14 shows an example of a semiconductor device, and in the example of FIG. 14, the semiconductor device is configured as a semiconductor laser. FIG. 14 is a cross-sectional view taken along a plane perpendicular to the light emitting direction of the semiconductor laser.

Referring to FIG. 14, this semiconductor laser includes an AlGaN low-temperature buffer layer 91, an n-type Al _0.03 Ga _0.97 N contact layer 92, an n-type Al _0.12 Ga _0.88 N cladding layer 93, and an n-type GaN guide layer on a sapphire substrate 90. 94, In _0.15 Ga _0.85 N / In _0.02 Ga _0.98 N multiple quantum well active layer 95, p-type Al _0.2 Ga _0.8 N layer 96, p-type GaN guide layer 97, p-type Al _0.12 Ga _0.88 N cladding layer 98, p-type A GaN contact layer 99 is sequentially stacked to form a stacked structure.

Part of the laminated structure is etched from the surface of the p-type GaN contact layer 99 until the n-type Al _0.03 Ga _0.97 N contact layer 92, n-type Al _0.03 Ga _0.97 N surface of the contact layer 92 is exposed. An n-side ohmic electrode 103 made of Ti / Al is formed on the exposed n-type Al _0.03 Ga _0.97 N contact layer 92.

In addition, the current confinement ridge structure 900 is formed by etching from the surface of the p-type GaN contact layer 99 to the middle of the p-type Al _0.12 Ga _0.88 N cladding layer 98. The ridge structure 900 is filled with Al _0.6 Ga _0.4 N polycrystal 100.

The p-type GaN contact layer 99 is exposed on the outermost surface of the ridge structure 900, and the p-side ohmic electrode 102 made of Ni / Au is formed there. Further, except for the electrode forming portion, SiO ₂ as an insulating protective film 101 is deposited. Further, the optical resonator end face is formed substantially perpendicular to the laminated structure and the current confinement ridge structure 900.

  Next, a method for manufacturing the semiconductor laser of FIG. 14 will be described. The crystal growth of the stacked structure of the semiconductor laser was performed by the MOCVD method.

  First, the sapphire substrate 90 was set in a reaction tube and heated at 1120 ° C. in hydrogen gas to clean the surface of the substrate 90.

Next, the temperature was lowered to 520 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen, and hydrogen, TMG and TMA were flowed, and a low-temperature AlGaN buffer layer 91 was deposited.

Next, the temperature is raised to 1050 ° C., TMG, TMI, and SiH ₄ are supplied in accordance with the composition using hydrogen as a carrier gas. The n-type Al _0.03 Ga _0.97 N contact layer 92 is 2 μm and the n-type Al _0.12 Ga _0.88 N clad The layer 93 was laminated to 0.7 μm, and the n-type GaN guide layer 94 was laminated to 0.1 μm.

Next, the supply of hydrogen gas is stopped, the atmosphere is changed to a mixed gas atmosphere of NH ₃ and nitrogen, the temperature is lowered to 810 ° C., TMG and TMI are supplied using hydrogen as a carrier gas, and In _0.15 Ga _0.85 N / In _0.02 A Ga _0.98 N multiple quantum well active layer 95 (2 pairs) was grown.

Next, the atmosphere is changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, the temperature is raised to 1050 ° C., hydrogen is used as a carrier gas, TMG, TMA, (EtCp) ₂ Mg are supplied according to the composition, and p-type Al _{The 0.2} Ga _0.8 N layer 96 was stacked to 20 nm, the p-type GaN guide layer 97 was stacked to 0.1 μm, the p-type Al _0.12 Ga _0.88 N cladding layer 98 was stacked to 0.7 μm, and the p-type GaN contact layer 99 was stacked to 0.2 μm.

p-type After the growth of the GaN contact layer 99, stopping TMG, the supply of (EtCp) ₂ Mg, mixed gas of NH ₃ and nitrogen (feed ratio NH ₃ and nitrogen 3: 2) was cooled down to room temperature in an atmosphere .

  Next, a stripe pattern having a width of 4 μm was repeatedly formed with a resist at a pitch of 1 mm using a resist, and dry etching was performed to a depth of about 0.6 μm using the resist pattern as a mask to form a ridge structure 900.

Next, the resist is removed, and then the wafer is set in the MOCVD apparatus again, and the mixed gas atmosphere of NH ₃ , nitrogen and hydrogen is raised, the temperature is raised to 730 ° C., and TMG and TMA are supplied using hydrogen as a carrier gas. Then, about 0.6 μm of Al _0.6 Ga _0.4 N polycrystal 100 was deposited, and the ridge structure 900 was embedded. At this time, the layer containing the p-type impurity becomes p-type by the second method of the second embodiment.

Then, after cooling in a mixed gas atmosphere of NH ₃ gas 5LM, nitrogen gas 15LM, and hydrogen gas 6LM, the wafer was taken out of the MOCVD apparatus, and a pattern in which the upper portion of the ridge structure 900 was removed with a resist was formed. Using this pattern as a mask, the Al _0.6 Ga _0.4 N polycrystal 100 on the ridge structure 900 was etched with a KOH solution to expose the p-type GaN contact layer 99 and planarize the surface.

Next, after removing the resist mask, a stripe pattern having a width of 500 μm covering the ridge structure 900 with a resist was repeatedly formed at a pitch of 1 mm. Using this resist pattern as a mask, the n-type Al _0.03 Ga _0.97 N contact layer 92 was exposed by dry etching of about 1.5 μm.

Next, about 0.5 μm of SiO _{2 serving} as the insulating protective film 101 was deposited on the surface of the laminated structure.

Next, the p-side ohmic electrode 102 was formed. The formation process of the p-side ohmic electrode 102 is as follows. That is, first, a resist stripe pattern was formed on the ridge structure 900 with a resist, and then the SiO ₂ film 101 was etched to expose the p-type GaN contact layer 99 on the ridge structure 900.

  Next, the resist was removed, and a resist stripe pattern having a width of about 450 μm was formed again. Ni / Au as a p-side ohmic electrode material was deposited on the ridge structure 900. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form the p-side ohmic electrode pattern 102 only on the semiconductor laser laminated structure. Thereafter, heat treatment was performed at 600 ° C. in a nitrogen atmosphere, and the p-side ohmic electrode 102 was formed on the p-type GaN contact layer 99.

Next, an n-side ohmic electrode 103 was formed. The formation process of the n-side ohmic electrode 103 is as follows. First, on the SiO ₂ film 101 on the n-type Al _0.03 Ga _0.97 N contact layer 92, a resist stripe pattern having a width of about 100 μm is formed with a resist, and then the SiO ₂ film 101 is etched to form an n-type Al _0.03 Ga _0.97 The N contact layer 92 was exposed.

  In this state, Ti / Al, which is an n-side ohmic electrode material, was deposited. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form an n-side ohmic electrode pattern. Thereafter, heat treatment was performed at 450 ° C. in a nitrogen atmosphere to form the n-side ohmic electrode 103.

  Next, the sapphire substrate 90 was thinly polished and divided so as to be substantially perpendicular to the ridge structure 900 to form an end face of the optical resonator.

  When a forward current was injected into the electrodes 102 and 103, light was emitted, and when the current was further increased, laser oscillation occurred. The oscillation wavelength was about 409 nm.

It is a figure which shows 1st Embodiment of the manufacturing method of the group III nitride semiconductor which concerns on this invention. It is a figure which shows a mode that hydrogen is taken in near the surface of a group III nitride crystal in the cooling process after group III nitride crystal growth. It is a figure which shows the specific example of the manufacturing process of the p-type group III nitride semiconductor of 1st Embodiment. It is a figure which shows 2nd Embodiment of the manufacturing method of the group III nitride semiconductor which concerns on this invention. It is a figure which shows the specific example of the manufacturing process of the p-type group III nitride semiconductor by the 1st method of 2nd Embodiment. It is a figure which shows the mode of the p-type group III nitride semiconductor manufactured by the 2nd method of 2nd Embodiment. It is a figure which shows the specific example of the manufacturing process of the p-type group III nitride semiconductor by the 2nd method of 2nd Embodiment. It is a figure for demonstrating the 3rd Embodiment of this invention. It is a figure for demonstrating the 5th Embodiment of this invention. It is a figure which shows an example of the semiconductor device which concerns on this invention. It is a figure which shows an example of the semiconductor device which concerns on this invention. It is a figure which shows an example of the semiconductor device which concerns on this invention. It is a figure which shows an example of the semiconductor device which concerns on this invention. It is a figure which shows an example of the semiconductor device which concerns on this invention. It is a figure for demonstrating the conventional method of manufacturing p-type group III nitride. It is a figure for demonstrating the conventional method of manufacturing p-type group III nitride. It is a figure which shows the concentration distribution of the film thickness direction of Mg and hydrogen (H) in p-type GaN by SIMS analysis. It is a figure which shows the pn junction diode as a specific example of the 3rd Embodiment of this invention. It is a figure which shows the current-voltage characteristic of the pn junction diode of FIG.

Explanation of symbols

1 Group III Nitride Crystal 2 Group III Nitride Crystal Surface Layer 3 p-type Group III Nitride Semiconductor 5 Group III Nitride Crystal 6 Predetermined Stacked Structure 7 p-type Group III Nitride Semiconductor 8 p-type Group III Nitride ( (p-type group III nitride laminated structure)
10, 40, 50, 70, 90, 110 Sapphire substrate 11, 21, 31, 41, 111 Low temperature GaN buffer layer 12, 13, 22, 32 GaN layer containing p-type impurities 33 SiN
23 GaN without doping impurities
42 High-temperature GaN buffer layer 43, 112 n-type GaN layer 44, 113 p-type GaN layer 45, 99 p-type GaN contact layers 47, 59, 82, 102 p-side ohmic electrode 48, 60, 83, 103 n-side ohmic electrode 46 SiN insulating protective film 49, 61 Wiring electrode 51 AlN low temperature buffer layer 52, 72, 92 n-type Al _0.03 Ga _0.97 N contact layer 53 n-type Al _0.07 Ga _0.93 N clad layer 54 In _0.17 Ga _0.83 N active layer 55 p-type Al _0.07 Ga _0.93 N cladding layer 56, 79 p-type GaN cap layer 57 p-type In _0.1 Ga _0.9 N contact layer 58, 81, 101 SiO ₂ insulating protective film 71, 91 AlGaN low-temperature buffer layer 73, 93 n-type Al _0.12 Ga _0.88 n cladding layer 74, 94 n-type GaN guide layer _{75,95 In 0.15 Ga 0.85 n / In} 0.02 G _0.98 N multiple quantum well active layer 76, 96 p-type Al _0.2 Ga _0.8 N layer 77,97 p-type GaN guide layer 78 and 98 p-type Al _0.12 Ga _0.88 N cladding layer 80 p-type In _0.1 Ga _0.9 N contact layer 100 Al _0.6 Ga _0.4 N polycrystal 114 p-side indium electrode 115 n-side indium electrode 800,900 ridge structure

Claims (12)

  A group III nitride crystal containing at least both p-type impurities and hydrogen is grown and cooled, and then a predetermined layered structure is formed on the group III nitride crystal, whereby the group III nitride crystal is formed. Is produced as a p-type group III nitride semiconductor. A method for producing a group III nitride semiconductor comprising:    2. The method for manufacturing a group III nitride semiconductor according to claim 1, wherein the predetermined laminated structure has a thickness of 0.5 [mu] m or more. A p-type group III nitride semiconductor containing at least p-type impurities is grown in an atmosphere containing hydrogen gas, and the temperature is lowered from the growth temperature in a gas atmosphere containing a nitrogen source containing NH ₃ after the crystal growth. A method for producing a group III nitride semiconductor.    2. The method of manufacturing a group III nitride semiconductor according to claim 1, wherein the outermost surface layer of the predetermined laminated structure is formed of a layer that can be grown in an atmosphere not containing hydrogen gas. Semiconductor manufacturing method.   5. The method for producing a group III nitride semiconductor according to claim 4, wherein the outermost surface layer of the predetermined laminated structure is a group III nitride containing at least In, and in this case, the group III nitride containing at least In is converted into hydrogen gas. Crystal growth in an atmosphere that does not contain hydrogen, or in an atmosphere in which nitrogen source gas and nitrogen gas are excessive with respect to hydrogen gas, and after completion of crystal growth of group III nitride containing at least In, cooling in a gas atmosphere containing at least nitrogen source A method for producing a group III nitride semiconductor.  6. The method for manufacturing a group III nitride semiconductor according to claim 1, wherein the p-type impurity is Mg.  A group III nitride semiconductor manufactured by the method for manufacturing a group III nitride semiconductor according to any one of claims 1 to 5.  A semiconductor device having at least a p-type semiconductor layer, wherein the group III nitride semiconductor according to claim 7 is used for the p-type semiconductor layer.  6. A p-type group III nitride semiconductor manufactured by the manufacturing method according to claim 5 and all or part of the p-type group III nitride multilayer structure, the p-type group III nitride multilayer structure having a p-side surface. A semiconductor device, wherein an ohmic electrode is formed.    10. The semiconductor device according to claim 8, wherein the semiconductor device is a semiconductor light emitting element.   The semiconductor device according to claim 8, wherein the semiconductor device is a semiconductor electronic device.   The semiconductor device according to claim 8, wherein the semiconductor device is a semiconductor light receiving element.

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