JP6832668B2 - Self-supporting board and manufacturing method of self-supporting board - Google Patents

Description

The present invention relates to a self-supporting substrate and a method for manufacturing a self-supporting substrate.

When a group III nitride semiconductor is epitaxially grown on a growth plane other than the C plane by the HVPE (Hydride Vapor Phase Epitaxy) method, a large amount of oxygen (impurity) may be doped into the crystal of the grown group III nitride semiconductor. is there. According to Patent Document 1, when a GaN crystal is grown on a plane inclined from the C plane, the concentration of impurities such as oxygen (O) doped in the crystal is 1 × 10 ¹⁹ / cm ^{3 to} 5 × 10 ¹⁹ / cm ³ It is stated that it will be higher.

Japanese Unexamined Patent Publication No. 2013-75815

When oxygen (O) is doped at a high concentration, it becomes difficult to control the carrier concentration by (1) Si doping and Ge doping (usually, ^{the carrier concentration is controlled to about 10 18} cm ^-3, but the concentration of O is controlled. (2) Due to the presence of O present on the surface of the GaN substrate, diffusion of the same atom, etc., (device) growth on it by the MOCVD (Metal Organic Chemical Vapor Deposition) method. May be hindered, and other problems may occur. Therefore, it is desired to reduce the oxygen (impurity) concentration. An object of the present invention is to control the concentration of oxygen (impurities) doped in the crystal of a group III nitride semiconductor when a group III nitride semiconductor is epitaxially grown on a growth surface other than the C plane by the HVPE method. To do.

According to the present invention
Consists of group III nitride semiconductors
It has a growth plane that is tilted 30 ° from the {11-22} plane and has a growth plane.
It contains O, which is the first impurity, and Si or Ge, which is the second impurity.
Assuming that the concentration of the first impurity measured by SIMS (Secondary Ion Spectrometry) is D1 and the concentration of the second impurity is D2, a self-supporting substrate satisfying 1.5 ≦ D1 / D2 ≦ 4 is provided.

Further, according to the present invention,
Consists of group III nitride semiconductors
It has a growth plane that is tilted 30 ° from the {11-22} plane and has a growth plane.
It contains O, which is the first impurity, and Si or Ge, which is the second impurity.
Assuming that the concentration of the first impurity measured by SIMS is D1 and the concentration of the second impurity is D2, a substrate having a group III nitride semiconductor layer satisfying 1.5 ≦ D1 / D2 ≦ 4 is provided. ..

Further, according to the present invention,
A preparatory step for preparing a base substrate having a surface inclined by 30 ° from the {11-22} surface as a growth surface, and
A growth step of growing a group III nitride semiconductor while doping O, which is a first impurity, and Si or Ge, which is a second impurity, on the base substrate by the HVPE (Hydride Vapor Phase Epitaxy) method. When,
Have,
In the growth step, assuming that the concentration of the first impurity measured by SIMS with the layer of the group III nitride semiconductor as the measurement target after the growth step is D1 and the concentration of the second impurity is D2, 1. A method for manufacturing a self-supporting substrate that optimizes the growth conditions of the group III nitride semiconductor so as to satisfy 5 ≦ D1 / D2 ≦ 4 is provided.

Further, according to the present invention,
A preparatory step for preparing a laminated body composed of a group III nitride semiconductor on a free-standing substrate and having a first layer having a plane inclined by 30 ° from the {11-22} plane as a growth plane.
A growth step of growing a group III nitride semiconductor while doping the first impurity O and the second impurity Si or Ge on the first layer by the HVPE method.
Have,
In the growth step, assuming that the concentration of the first impurity measured by SIMS with the layer of the group III nitride semiconductor as the measurement target after the growth step is D1 and the concentration of the second impurity is D2, 1. A method for manufacturing a substrate that optimizes the growth conditions of the group III nitride semiconductor so as to satisfy 5 ≦ D1 / D2 ≦ 4 is provided.

According to the present invention, it is possible to control the concentration of oxygen (impurity) doped in the crystal of the group III nitride semiconductor when the group III nitride semiconductor is epitaxially grown on the growth plane other than the C plane by the HVPE method. it can.

It is a flowchart which shows an example of the process flow of the manufacturing method of this embodiment. It is a side schematic diagram which shows an example of the laminated body which formed the group III nitride semiconductor layer on the base substrate of this embodiment. It is a schematic diagram of the HVPE apparatus. It is a side schematic diagram which shows an example of the laminated body which formed the group III nitride semiconductor layer on the self-supporting substrate of this embodiment. It is a figure which shows the SIMS analysis result of Example 1. FIG. It is a figure which shows the SIMS analysis result of the comparative example 1. FIG.

Hereinafter, embodiments of the method for manufacturing a self-supporting substrate of the present invention will be described with reference to the drawings. It should be noted that the figure is merely a schematic view for explaining the configuration of the invention, and the size, shape, number, ratio of different member sizes, etc. of each member are not limited to those shown.

First, the outline of the present embodiment will be described. When a group III nitride semiconductor is epitaxially grown on a growth surface other than the C plane by the HVPE method, O (impurities) are likely to be unintentionally doped in a high concentration in the crystal of the grown group III nitride semiconductor. For example, the concentration is as high as M × 10 ¹⁹ / cm ³ (1 ≦ M ≦ 9). It is presumed that the source of O is a reaction tube or the like made of _{SiO 2} , which is a member of the HVPE apparatus.

The present inventors adjust the growth conditions of the crystal of the group III nitride semiconductor, dope other impurities, specifically at least one of Si and Ge, into the crystal of the group III nitride semiconductor, and concentrate these. It was found that when the value is increased, the concentration of O in the crystal of the group III nitride semiconductor decreases. Further, by optimizing the V / III ratio, the present inventors dope at least one of Si and Ge in a large amount in the crystal of the group III nitride semiconductor, and O in the crystal of the group III nitride semiconductor. We have found that the concentration can be reduced.

In the present embodiment, when the group III nitride semiconductor is epitaxially grown on a growth surface other than the C plane by the HVPE method, the V / III ratio is optimized and Si is doped in a large amount in the crystal of the group III nitride semiconductor. The concentration of O in the crystal is reduced. An example of high-concentration doping of Ge will be described in the second embodiment.

Next, an example of the method for manufacturing the self-supporting substrate of the present embodiment will be described with reference to the flowchart of FIG. As shown in the figure, the method for manufacturing a self-supporting substrate of the present embodiment includes a preparation step S10 and a growth step S20.

In the preparation step S10, a base substrate having a surface different from the C surface as a growth surface is prepared. The base substrate may be a substrate composed of a group III nitride semiconductor, or may be a dissimilar substrate such as a sapphire substrate.

In the growth step S20, a group III nitride semiconductor is grown on the base substrate by the HVPE method while doping O, which is the first impurity, and Si, which is the second impurity. The first impurity, O, may be an impurity that is unintentionally doped using, for example, a member of the HVPE apparatus 100 as a source.

As a result of this step, as shown in FIG. 2, a laminate of the base substrate 10 and the group III nitride semiconductor layer 20 is obtained. In the present embodiment, such a laminated body can be used as a self-standing substrate, or a self-supporting substrate can be obtained by removing the base substrate 10 from the laminated body by polishing or the like. Further, a part thereof may be cut out from the group III nitride semiconductor layer 20 by slicing or the like to form a self-standing substrate.

In the growth step S20, assuming that the concentration of the first impurity measured by SIMS with the group III nitride semiconductor layer 20 as the measurement target after the growth step S20 is D1 and the concentration of the second impurity is D2, it is 1.5. The growth conditions of the group III nitride semiconductor are optimized so as to satisfy ≦ D1 / D2 ≦ 4. For example, in the growth step S20, the group III nitride semiconductor is grown under growth conditions in which the V / III ratio is 20 or more and 50 or less, preferably 30 or more and 50 or less. Other growth conditions are the same as those of the prior art, and for example, the growth temperature can be 900 ° C. or higher and 1100 ° C. or lower. As shown in the following examples, when the group III nitride semiconductor is grown under the growth conditions, the above 1.5 ≦ D1 / D2 ≦ 4 can be satisfied.

Here, an example of epitaxially growing GaN in the hydride vapor phase growth (HVPE) apparatus 100 will be described with reference to FIG.

The illustrated HVPE device 100 includes a reaction tube 121 and a substrate holder 123 provided in the reaction tube 121. The reaction tube 121 is made of SiO ₂ (quartz or the like). The substrate holder 123 holds the substrate 41 (the substrate 10 described above). Further, the HVPE apparatus 100 includes a group III raw material gas supply unit 139 that supplies the group III raw material gas into the reaction tube 121, and a nitrogen raw material gas supply unit 137 that supplies the nitrogen raw material gas into the reaction tube 121. Further, the HVPE device 100 includes a gas discharge pipe 135 and heaters 129 and 130.

The substrate holder 123 is rotatably provided on the downstream side of the reaction tube 121 by a rotating shaft 132. The gas discharge pipe 135 is provided on the downstream side of the substrate holder 123 in the reaction pipe 121.

The Group III raw material gas supply unit 139 includes a gas supply pipe 126, a source boat 128, a Group III (Ga) raw material 127, and a layer of the reaction pipe 121 under the shielding plate 136.

The nitrogen source gas supply unit 137 includes a gas supply pipe 124 and a layer above the shielding plate 136 of the reaction pipe 121.

The group III raw material gas supply unit 139 generates a halide (for example, GaCl) of a group III atom and supplies the halide (for example, GaCl) to the surface of the base substrate 41 held by the substrate holder 123.

The supply port of the gas supply pipe 126 is arranged on the upstream side in the group III raw material gas supply unit 139. Therefore, the supplied hydrogen halide gas (for example, HCl gas) comes into contact with the group III raw material 127 in the source boat 128 in the group III raw material gas supply unit 139.

As a result, the halogen-containing gas supplied from the gas supply pipe 126 comes into contact with the surface of the group III raw material 127 in the source boat 128 or the volatilized group III molecules, and halogenates the group III molecules to form a group III halide. Produces Group III source gas containing. A heater 129 is arranged around the group III raw material gas supply unit 139, and the temperature inside the group III raw material gas supply unit 139 is maintained at, for example, about 800 to 900 ° C.

The upstream side of the reaction tube 121 is divided into two layers by a shielding plate 136. Ammonia supplied from the gas supply pipe 124 passes through the nitrogen raw material gas supply unit 137 located above the shielding plate 136 in the figure, and decomposition is promoted by heat. A heater 129 is arranged around the nitrogen raw material gas supply unit 137, and the temperature inside the nitrogen raw material gas supply unit 137 is maintained at, for example, about 800 to 900 ° C.

The base substrate 41 held by the substrate holder 123 is arranged in the growth region 122 located on the right side in the drawing, and the group III nitride semiconductor such as GaN is grown in the growth region 122. A heater 130 is arranged around the growth region 122, and the temperature inside the growth region 122 is maintained at, for example, about 1000 ° C. to 1050 ° C.

As shown in the following examples, the growth of the group III nitride semiconductor is performed _{by using an HVPE device in which a part of the member (example: reaction tube 121) is composed of SiO 2} (quartz or the like) and the V / III ratio is high. When the growth condition is 20 or more and 50 or less, Si (impurity) is doped in the crystal of the grown group III nitride semiconductor. It is presumed that the source of Si is SiO ₂ (quartz or the like) or the like constituting the reaction tube 121. As described above, according to the present embodiment, it is not necessary to separately prepare a Si source, and Si can be doped at a high concentration only by optimizing the growth conditions.

According to the method for manufacturing a self-supporting substrate of this embodiment, the following self-supporting substrate can be obtained.

Consists of group III nitride semiconductors
It has a growth surface composed of a surface different from the C surface,
It contains O, which is the first impurity, and Si or Ge, which is the second impurity.
Assuming that the concentration of the first impurity measured by SIMS is D1 and the concentration of the second impurity is D2, a self-supporting substrate satisfying 1.5 ≦ D1 / D2 ≦ 4.

That is, according to the production method of the present embodiment, a self-supporting substrate can be obtained in which the ratio of the concentration of the second impurity to the concentration of the first impurity is sufficiently increased and the concentration of the first impurity is sufficiently reduced. Then, according to the manufacturing method of the present embodiment, a self-standing substrate in which ^{the concentration D1 of the first impurity is reduced to 5 × 10 17} / cm ³ ≦ D1 ≦ 9 × 10 ¹⁷ / cm ^{3 can be obtained.} As a result, according to the production method of the present embodiment, the carrier concentration can be controlled by impurities other than O (eg, Si). Further, the inconvenience that the (device) growth on the surface of the GaN substrate is hindered by the MOCVD method due to the presence of O present on the surface of the GaN substrate, the diffusion of the atoms, and the like can be alleviated.

Further, according to the manufacturing method of the present embodiment, assuming that the Hall concentration measured by the Hall effect measuring device for the self-standing substrate is H, (D1 + D2) × 0.7 ≦ H ≦ (D1 + D2) × 1.3. Can be met. That is, the hole concentration is substantially equal to the sum of the concentration of the first impurity and the concentration of the second impurity. From this, it can be seen that both the first impurity and the second impurity function as carriers. In the case of the present embodiment, the concentration of the first impurity is reduced, but the second impurity to be doped instead also functions as a carrier, so that a sufficient carrier concentration can be secured.

<Modification example 1>
If the concentration of the first impurity measured by SIMS is D1 and the concentration of the second impurity is D2, which contains O which is the first impurity and Si which is the second impurity, 1.5 ≦ D1 /. The layer of the group III nitride semiconductor satisfying D2 ≦ 4 is not limited to that formed on the base substrate 10 (20 in FIG. 2).

For example, in the preparation step S10, a first layer 40 composed of a group III nitride semiconductor and having a surface different from the C surface as a growth surface was formed on the self-standing substrate 30 composed of the group III nitride semiconductor. A laminate may be prepared. The first layer 40 may be formed directly above the free-standing substrate 30, or may be formed on the free-standing substrate 30 via another layer (either a single layer or a plurality of layers).

Then, in the growth step S20, the group III nitride semiconductor may be epitaxially grown directly above the first layer 40 of such a laminate. The details of the growth step S20 are as described above.

According to the modification, as shown in FIG. 4, a substrate having a free-standing substrate 30, a first layer 40, and a group III nitride semiconductor layer 50 can be obtained.

The group III nitride semiconductor layer 50 is composed of a group III nitride semiconductor and has a growth surface formed of a surface different from the C surface. Then, assuming that the concentration of the first impurity measured by SIMS is D1 and the concentration of the second impurity is D2, which contains O which is the first impurity and Si or Ge which is the second impurity. 5 ≦ D1 / D2 ≦ 4 is satisfied.

That is, according to the modification, a substrate having a group III nitride semiconductor layer in which the ratio of the second impurity is sufficiently increased and the concentration of the first impurity is sufficiently reduced can be obtained. Then, according to the modification, the concentration D1 of the first impurity in the group III nitride semiconductor layer can be reduced to ^{5 × 10 17} / cm ³ ≦ D1 ≦ 9 × 10 ¹⁷ / cm ^3. As a result, the same action and effect as described above can be realized.

Further, according to the modification, assuming that the Hall concentration measured by the Hall effect measuring device with respect to the self-supporting substrate is H, (D1 + D2) × 0.7 ≦ H ≦ (D1 + D2) × 1.3 can be satisfied. it can. That is, the hole concentration is substantially equal to the sum of the concentration of the first impurity and the concentration of the second impurity. From this, it can be seen that both the first impurity and the second impurity function as carriers. In the case of the present embodiment, the concentration of the first impurity is reduced, but the second impurity to be doped instead also functions as a carrier, so that a sufficient carrier concentration can be secured.

<Modification 2>
Ge can be used instead of Si as the second impurity. _{For example, GeCl 4} can be used as a source of Ge (second impurity). Then, H _{2 gas (carrier gas) is passed through GeCl 4} (liquid) whose temperature is maintained at about 10 ° C. _{, and GeCl 4} is sent into the reactor as vapor. For example, the partial pressure _{of GeCl 4 in} ^{the reactor is about 1 × 10-6} atm. As a source of Ge (second impurity), a member containing Ge may be installed in the reactor.

Then, as in the case where the second impurity is Si, the growth conditions of the group III nitride semiconductor in the growth step S20 are optimized so as to satisfy 1.5 ≦ D1 / D2 ≦ 4. For example, in the growth step S20, the group III nitride semiconductor is grown under growth conditions in which the V / III ratio is 20 or more and 50 or less, preferably 30 or more and 50 or less. Also in the modified example, the same action and effect as described above can be realized.

<Example 1>
A GaN substrate having a surface (11-22) tilted by about 30 ° as a growth surface was prepared. Then, GaN was epitaxially grown on the GaN substrate under the following growth conditions by the HVPE apparatus described with reference to FIG.

Growth temperature: 1040 ° C
V / III ratio: 40
Growth time: 120 minutes Growth rate: 7.5 μm / h

FIG. 5 shows the results of SIMS analysis of the concentrations of O, Si, and C in the epitaxially grown GaN. The concentration of O was 7 × 10 ¹⁷ / cm ³ , and the carrier concentration calculated by Hall measurement was 1.2 × 10 ¹⁸ / cm ³ .

<Example 2>
A GaN substrate having a surface (11-22) tilted by about 30 ° as a growth surface was prepared. Then, GaN was epitaxially grown on the GaN substrate under the following growth conditions by the HVPE apparatus described with reference to FIG.

Growth temperature: 1040 ° C
V / III ratio: 20
Growth time: 60 minutes Growth rate: 239 μm / h

FIG. 6 shows the results of SIMS analysis of the concentrations of O, Si, and C in the pivotally grown GaN. The concentration of O was 5 × 10 ¹⁸ / cm ³ , and the carrier concentration calculated by Hall measurement was 5.7 × 10 ¹⁸ / cm ³ .

From the above, it can be seen that the Si concentration and the O concentration can be adjusted by optimizing the V / III ratio. Then, it can be seen that the concentration of Si can be increased and the concentration of O can be decreased by optimizing the V / III ratio. In both Example 1 and Example 2, the concentration of O ^{is smaller than M × 10 19} / cm ³ (1 ≦ M ≦ 9). Further, the sum of the Si concentration and the O concentration is almost the same as the Hall concentration, and it can be seen that these impurities function as carriers.

Hereinafter, an example of the reference form will be added.
1. 1. Consists of group III nitride semiconductors
It has a growth surface composed of a surface different from the C surface,
It contains O, which is the first impurity, and Si or Ge, which is the second impurity.
Assuming that the concentration of the first impurity measured by SIMS is D1 and the concentration of the second impurity is D2, a self-supporting substrate satisfying 1.5 ≦ D1 / D2 ≦ 4.
2. 2. In the self-supporting substrate according to 1.
Assuming that the Hall concentration measured by the Hall effect measuring device is H,
A self-supporting substrate that satisfies (D1 + D2) × 0.7 ≦ H ≦ (D1 + D2) × 1.3.
3. 3. In the self-supporting substrate according to 1 or 2,
A self-standing substrate that satisfies 5 × 10 ¹⁷ / cm ³ ≦ D1 ≦ 9 × 10 ¹⁷ / cm ^3.
4. Consists of group III nitride semiconductors
It has a growth surface composed of a surface different from the C surface,
It contains O, which is the first impurity, and Si or Ge, which is the second impurity.
Assuming that the concentration of the first impurity measured by SIMS is D1 and the concentration of the second impurity is D2, a substrate having a group III nitride semiconductor layer satisfying 1.5 ≦ D1 / D2 ≦ 4.
5. In the substrate according to 4.
Assuming that the Hall concentration measured by the Hall effect measuring device is H,
A substrate that satisfies (D1 + D2) × 0.7 ≦ H ≦ (D1 + D2) × 1.3.
6. In the substrate according to 4 or 5.
A substrate satisfying 5 × 10 ¹⁷ / cm ³ ≦ D1 ≦ 9 × 10 ¹⁷ / cm ^3.
7. A preparatory process for preparing a base substrate having a surface different from the C surface as a growth surface, and
A growth step of growing a group III nitride semiconductor while doping O, which is a first impurity, and Si or Ge, which is a second impurity, on the base substrate by the HVPE method.
Have,
In the growth step, assuming that the concentration of the first impurity measured by SIMS with the layer of the group III nitride semiconductor as the measurement target after the growth step is D1 and the concentration of the second impurity is D2, 1. A method for manufacturing a self-supporting substrate that optimizes the growth conditions of the group III nitride semiconductor so as to satisfy 5 ≦ D1 / D2 ≦ 4.
8. In the method for manufacturing a self-supporting substrate according to 7.
In the growth step, a method for manufacturing a self-supporting substrate for growing a group III nitride semiconductor under growth conditions having a V / III ratio of 20 or more and 50 or less.
9. A preparatory step for preparing a laminated body composed of a group III nitride semiconductor and having a first layer having a surface different from the C surface as a growth surface formed on the self-supporting substrate.
A growth step of growing a group III nitride semiconductor while doping the first impurity O and the second impurity Si or Ge on the first layer by the HVPE method.
Have,
In the growth step, assuming that the concentration of the first impurity measured by SIMS with the layer of the group III nitride semiconductor as the measurement target after the growth step is D1 and the concentration of the second impurity is D2, 1. A method for manufacturing a substrate that optimizes the growth conditions of the group III nitride semiconductor so as to satisfy 5 ≦ D1 / D2 ≦ 4.
10. In the method for manufacturing a substrate according to 9.
In the growth step, a method for manufacturing a substrate for growing a group III nitride semiconductor under growth conditions having a V / III ratio of 20 or more and 50 or less.

10 Base substrate 20 Group III nitride semiconductor layer 30 Self-supporting substrate 40 First layer 50 Group III nitride semiconductor layer 100 HVPE device 121 Reaction tube 122 Growth area 123 Substrate holder 124 Gas supply tube 125 Piping 126 Gas supply tube 127 Group III Raw material 128 Source boat 129 Heater 130 Heater 132 Rotating shaft 135 Gas discharge pipe 136 Shielding plate 137 Nitrogen raw material gas supply unit 139 Group III raw material gas supply unit

Claims (10)

Consists of group III nitride semiconductors
It has a growth plane that is tilted 30 ° from the {11-22} plane and has a growth plane.
It contains O, which is the first impurity, and Si or Ge, which is the second impurity.
Assuming that the concentration of the first impurity measured by SIMS (Secondary Ion Spectrometry) is D1 and the concentration of the second impurity is D2, a self-supporting substrate satisfying 1.5 ≦ D1 / D2 ≦ 4. In the self-supporting substrate according to claim 1,
Assuming that the Hall concentration measured by the Hall effect measuring device is H,
A self-supporting substrate that satisfies (D1 + D2) × 0.7 ≦ H ≦ (D1 + D2) × 1.3. In the self-supporting substrate according to claim 1 or 2.
A self-standing substrate that satisfies 5 × 10 ¹⁷ / cm ³ ≦ D1 ≦ 9 × 10 ¹⁷ / cm ^3. Consists of group III nitride semiconductors
It has a growth plane that is tilted 30 ° from the {11-22} plane and has a growth plane.
It contains O, which is the first impurity, and Si or Ge, which is the second impurity.
Assuming that the concentration of the first impurity measured by SIMS is D1 and the concentration of the second impurity is D2, a substrate having a group III nitride semiconductor layer satisfying 1.5 ≦ D1 / D2 ≦ 4. In the substrate according to claim 4,
Assuming that the Hall concentration measured by the Hall effect measuring device is H,
A substrate that satisfies (D1 + D2) × 0.7 ≦ H ≦ (D1 + D2) × 1.3. In the substrate according to claim 4 or 5,
A substrate satisfying 5 × 10 ¹⁷ / cm ³ ≦ D1 ≦ 9 × 10 ¹⁷ / cm ^3. A preparatory step for preparing a base substrate having a surface inclined by 30 ° from the {11-22} surface as a growth surface, and
A growth step of growing a group III nitride semiconductor while doping O, which is a first impurity, and Si or Ge, which is a second impurity, on the base substrate by the HVPE (Hydride Vapor Phase Epitaxy) method. When,
Have,
In the growth step, assuming that the concentration of the first impurity measured by SIMS with the layer of the group III nitride semiconductor as the measurement target after the growth step is D1 and the concentration of the second impurity is D2, 1. A method for manufacturing a self-supporting substrate that optimizes the growth conditions of the group III nitride semiconductor so as to satisfy 5 ≦ D1 / D2 ≦ 4. In the method for manufacturing a self-supporting substrate according to claim 7.
In the growth step, a method for manufacturing a self-supporting substrate for growing a group III nitride semiconductor under growth conditions having a V / III ratio of 20 or more and 50 or less. A preparatory step for preparing a laminated body composed of a group III nitride semiconductor on a free-standing substrate and having a first layer having a plane inclined by 30 ° from the {11-22} plane as a growth plane.
A growth step of growing a group III nitride semiconductor while doping the first impurity O and the second impurity Si or Ge on the first layer by the HVPE method.
Have,
In the growth step, assuming that the concentration of the first impurity measured by SIMS with the layer of the group III nitride semiconductor as the measurement target after the growth step is D1 and the concentration of the second impurity is D2, 1. A method for manufacturing a substrate that optimizes the growth conditions of the group III nitride semiconductor so as to satisfy 5 ≦ D1 / D2 ≦ 4. In the method for manufacturing a substrate according to claim 9,
In the growth step, a method for manufacturing a substrate for growing a group III nitride semiconductor under growth conditions having a V / III ratio of 20 or more and 50 or less.

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