JP2014138147A - Nitride semiconductor growth substrate and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable formation of an element which uses a Ga-containing nitride semiconductor and has good characteristics by a substrate composed of a dissimilar material and a template substrate using AlN.SOLUTION: A nitride semiconductor growth substrate comprises: a substrate 101 composed of a material dissimilar to that of a nitride semiconductor; a semiconductor thin film 102 which is formed on the substrate 101 and composed of AlN; and a cap layer 103 which is formed on the semiconductor thin film 102 and composed of AlO. The cap layer 103 is formed in contact with a surface of the semiconductor thin film 102. The cap layer 103 is formed to cover the semiconductor film 102. The substrate 101 is composed of silicon, for example.

Description

  The present invention relates to a nitride semiconductor growth substrate on which a nitride semiconductor layer is formed and a method for manufacturing the same.

  Nitride semiconductors such as GaN have characteristics such as high breakdown field strength, high thermal conductivity, and high electron saturation speed, and are excellent as materials for high-frequency high-power devices. For example, in a heterojunction structure having a GaN buffer layer and an AlGaN barrier layer, electrons are accumulated at a high concentration in the vicinity of the heterojunction interface, and so-called two dimensional electron gas (2DEG) is formed. This 2DEG can travel in an undoped GaN layer in which there are no conductive impurities that cause scattering, and thus exhibits high electron mobility. Therefore, the element having the above-described heterojunction structure can be operated as a so-called high electron mobility transistor (HEMT).

  In the case of manufacturing an optical device / electronic device using a stacked structure composed of nitride semiconductors including the above-described example, a desired stacked structure is manufactured by sequentially growing nitride semiconductor crystals on a substrate. A substrate usually used for growing such a nitride semiconductor crystal is made of a so-called dissimilar material such as sapphire, silicon carbide or silicon. This is because the production of the nitride semiconductor substrate is technically very difficult and cannot be easily obtained. In particular, while attention has been focused on application as a high-power device, silicon substrates from which large-diameter substrates can be easily obtained have been widely used as growth substrates (see Non-Patent Documents 1, 2, and 3). .

  Here, when a layer containing Ga, which is a nitride semiconductor, is formed on a silicon substrate, abnormal growth such as etching of the silicon substrate by a meltback etching reaction occurs when Ga contacts the silicon substrate. For this reason, usually, an AlN layer is grown on a silicon substrate to avoid meltback etching in a state where Ga does not contact the silicon substrate.

  As a specific example, a case where a multilayer structure for HEMT having a barrier layer made of AlGaN and a channel layer made of GaN is grown on a silicon substrate will be described. First, a silicon substrate subjected to hydrogen termination with HF as a pretreatment is loaded into a growth chamber of a growth apparatus such as a metal organic chemical vapor deposition (MOCVD) apparatus or a molecular beam epitaxy (MBE) apparatus. Is sealed.

  Next, the apparatus is operated to raise the substrate temperature to the growth temperature. Next, an aluminum source gas and a nitrogen source gas (in the case of MOCVD, for example, trimethylaluminum and ammonia) are supplied to grow AlN on the silicon substrate. Next, supply of Ga source gas is started, a buffer structure composed of AlGaN that is GaN, AlN, or a mixed crystal thereof is grown, and then a GaN channel layer and an AlGaN barrier layer are grown (see Non-Patent Document 4). ).

  However, with the method described above, the possibility that Ga contacts the silicon substrate cannot be excluded. For example, in the case where the device manufacturing with the nitride semiconductor layer laminated structure described above is performed continuously, a large amount of Ga deposits remain on the wall surface or the substrate support table in the growth chamber due to the device manufacturing performed previously. Yes. The deposit containing Ga may adhere to the silicon substrate during the next element manufacturing, and may cause the above-described meltdown etching.

  In order to prevent this problem, a multilayer substrate made of a nitride semiconductor containing Ga for element formation as described above is used on an AlN film already formed using a template substrate in which an AlN film is previously deposited on a silicon substrate. Technology to grow is proposed. The growth of the AlN film for forming the template substrate may be performed by an apparatus that does not deposit a material containing gallium. Actually, a template substrate on which an AlN film has already been formed is available (see Non-Patent Document 5).

IMEC annual report 2011 (http://annualreport.imec.be/Domains/Energy/GaN-technology/page.aspx/1096) AZZURRO Semiconductors Product Guide (http://www.azzurro-semiconductors.com/products/power-semiconductor-wafers) NTT Advanced Technology Corporation Product Information (http://keytech.ntt-at.co.jp/electro/prd_1002.html) A. Dadgar, A. Strittmatter, J. Blasing, M. Poschenrieder, O. Contreras, P. Veit, 1 T. Riemann, F. Bertram, A. Reiher, A. Krtschil, A. Diez, T. Hempel, T Finger, A. Kasic, M. Schubert, D. Bimberg, FA Ponce, J. Christen, and A. Krost, "Metalorganic chemical vapor phase epitaxy of gallium-nitride on silicon," Physica Status Solidi C, vol.0, no.6, pp.1583-1606, 2003. Kyma Technologies Product Information (http://www.kymatech.com/products/template-products/aln-templates/aln-template-detail) A. Yamamoto, D. Hironaga, A. Mihara, Y. Muramatsu, K. Sugita, AG Bhuiyan, A. Hashimoto, N. Shigekawa, N. Watanabe, "MOVPE growth of InxGa1-xN (x ~ 0.5) on Si ( 111) substrates with a pn junction on the surface ", submitted to Physica Status Solidi C.

By the way, AlN is an insulator because its band gap is as large as 6.2 eV, and it has been considered effective in manufacturing a high power transistor that requires a particularly high breakdown voltage. However, there is a lattice mismatch of approximately 20% between silicon and AlN, and the thermal expansion coefficient mismatch is also a very large combination. Due to this mismatch, there is a high density of threading dislocations in the AlN film grown on the silicon substrate, far exceeding 10 ¹⁰ cm ^-2 . Due to the existence of threading dislocations, there is almost no insulation of AlN grown on the silicon substrate, but a relatively easy current flow.

  Non-Patent Document 6 discloses a current measured by forming an electrode metal on the front surface and back surface of a sample on which n-type InGaN is grown on a template substrate obtained by growing AlN on a conductive (p-type) silicon substrate.・ Voltage characteristics have been reported. If AlN is an insulator and exhibits high resistance, almost no current should flow, but the characteristics are almost completely ohmic as shown in FIG. a)).

  As described above, AlN used for a template substrate using a substrate made of a different material has a low resistance due to the presence of high-density threading dislocations, and cannot exhibit the insulation inherent in the substance. There is no advantage for the application. As described above, a template substrate using AlN and a substrate made of a different material that is currently provided cannot obtain high insulation properties, and an element having good characteristics made of a nitride semiconductor containing Ga cannot be formed. there were.

  The present invention has been made in order to solve the above problems, and is a template substrate using a substrate made of different materials and AlN, and having a good characteristic using a nitride semiconductor containing Ga. It aims to be able to form.

  A nitride semiconductor growth substrate according to the present invention includes a substrate made of a material different from a nitride semiconductor, a semiconductor thin film made of AlN formed on the substrate, and a surface of the semiconductor thin film on the semiconductor thin film. And a cap layer formed so as to cover the semiconductor thin film, and the cap layer is made of an oxide of Al, Ga, or In.

In the nitride semiconductor growth substrate, the cap layer is made of Al ₂ O ₃ . The substrate may be made of silicon.

  The method for manufacturing a nitride semiconductor growth substrate according to the present invention includes a first step of forming a semiconductor thin film made of AlN on a substrate made of a material different from a nitride semiconductor, and a semiconductor thin film. And a second step of forming a cap layer that is in contact with the surface of the semiconductor thin film and covers the semiconductor thin film, and the cap layer is made of an oxide of Al, Ga, or In. For example, the substrate may be made of silicon.

In the method for manufacturing a nitride semiconductor growth substrate, the cap layer is made of Al ₂ O ₃ . Here, in this case, when the substrate is made of silicon, the first step includes a step of hydrogen-termination of the surface of the substrate, a step of forming an Al monoatomic film on the surface of the hydrogen-terminated substrate, It is preferable to include a step of depositing AlN on the atomic film and forming a semiconductor thin film in which the monoatomic film is homogenized on the deposited AlN.

  As described above, according to the present invention, it is possible to form an excellent element using a nitride semiconductor containing Ga on a template substrate using a substrate made of different materials and AlN. Is obtained.

FIG. 1 is a cross-sectional view showing a configuration of a nitride semiconductor growth substrate in an embodiment of the present invention. FIG. 2A is a cross-sectional view schematically showing a state in each step according to the method for manufacturing the nitride semiconductor growth substrate in the embodiment of the present invention. FIG. 2B is a cross-sectional view schematically showing a state in each step according to the method for manufacturing the nitride semiconductor growth substrate in the embodiment of the present invention. FIG. 2C is a cross-sectional view schematically showing a state in each step according to the method for manufacturing the nitride semiconductor growth substrate in the embodiment of the present invention. FIG. 2D is a cross-sectional view schematically showing a state in each step according to the method for manufacturing the nitride semiconductor growth substrate in the embodiment of the present invention. FIG. 2E is a cross-sectional view schematically showing a state in each step according to the method for manufacturing the nitride semiconductor growth substrate in the embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a structure in which a nitride semiconductor layer is grown on a nitride semiconductor growth substrate of the present invention. FIG. 4A is an explanatory diagram for explaining the formation of a nitride semiconductor layer using the nitride semiconductor growth substrate in the embodiment of the present invention. FIG. 4B is an explanatory diagram illustrating formation of a nitride semiconductor layer using the nitride semiconductor growth substrate in the embodiment of the present invention. FIG. 4C is an explanatory diagram illustrating formation of a nitride semiconductor layer using the nitride semiconductor growth substrate in the embodiment of the present invention. FIG. 4D is an explanatory diagram illustrating formation of the nitride semiconductor layer using the nitride semiconductor growth substrate in the embodiment of the present invention. FIG. 5 is a characteristic diagram showing a symmetric reflection spectrum from (0002) by X-ray diffraction. FIG. 6 is a cross-sectional view schematically showing a state in which an AlGaN / GaN heterostructure is formed on the nitride semiconductor growth substrate of the present invention. FIG. 7 is a cross-sectional view schematically showing a state in which an AlGaN / GaN heterostructure and electrodes are formed on the nitride semiconductor growth substrate of the present invention. FIG. 8 is a characteristic diagram showing a result of measuring a current flowing when a voltage is applied between the electrode 701 and the electrode 702 shown in FIG. FIG. 9 shows measurement by forming an electrode metal on the surface of the sample on which n-type InGaN is grown and on the rear surface of the substrate on the template substrate obtained by growing AlN on the conductive silicon substrate shown in Non-Patent Document 6. FIG. 6 is a characteristic diagram showing the current / voltage characteristics obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a nitride semiconductor growth substrate according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a configuration of a nitride semiconductor growth substrate in an embodiment of the present invention.

The substrate for growing a nitride semiconductor includes a substrate 101 made of a material different from a nitride semiconductor, a semiconductor thin film 102 made of AlN formed on the substrate 101, and an Al formed on the semiconductor thin film 102. _{And a} cap layer 103 made of ₂ O ₃ . The cap layer 103 is formed in contact with the surface of the semiconductor thin film 102. The cap layer 103 is formed so as to cover the semiconductor thin film 102. The substrate 101 is made of, for example, silicon.

  The cap layer 103 has a role of protecting the surface of the semiconductor thin film 102. In addition, the cap layer 103 is generated at the interface between the substrate 101 and the semiconductor thin film 102 due to the mismatch between the substrate 101 and the semiconductor thin film 102, and threading dislocations propagating in the semiconductor thin film 102 toward the surface are generated. , And has a function of stopping propagation to the nitride semiconductor layer formed (grown) thereon. Thus, for example, if an AlN layer is grown on the cap layer 103, this layer can be brought into a state with a lower threading dislocation density. As a result, by growing the AlN layer using the nitride semiconductor growth substrate of the present embodiment, the resistivity can be increased and a higher breakdown voltage can be realized for application to a high power transistor.

  Next, a method for manufacturing a nitride semiconductor growth substrate in an embodiment of the present invention will be described with reference to FIGS. 2A to 2C. 2A to 2C are cross-sectional views schematically showing states in respective steps according to the method for manufacturing a nitride semiconductor growth substrate in the embodiment of the present invention.

  First, for example, the surface of the substrate 101 made of single crystal silicon is terminated with hydrogen atoms by pretreatment with HF or the like.

  Next, as shown in FIGS. 2A, 2B, and 2C, a semiconductor thin film 102 made of AlN is formed on the substrate 101 (first step). For example, the semiconductor thin film 102 is formed using an ECR (Electron Cycrotron Resonance) plasma film forming apparatus.

  First, the substrate 101 that has been pretreated as described above is loaded (arranged) in the film forming chamber of the ECR plasma film forming apparatus. The substrate temperature is room temperature (about 20 to 25 ° C.). Next, the ECR plasma film forming apparatus is operated to deposit Al single atoms 202 in Ar plasma on the substrate 101 whose surface is terminated with hydrogen 201 as shown in FIG. 2A. As a result of the deposition of the Al monoatom 202, hydrogen that has terminated the surface of the substrate 101 by the pretreatment is replaced with Al, and an Al monoatomic film in which Al is bonded to Si on the surface of the substrate 101 as shown in FIG. 2B. 203 is formed.

  Next, using Al and nitrogen, as shown in FIG. 2B, Al single atoms 202 and N single atoms 204 are deposited in Ar plasma. As a result of this deposition, the Al monoatomic film 203 deposited at an early stage is homogenized with AlN, and the Al monoatomic film disappears. As shown in FIG. 2C, a semiconductor thin film 102 made of AlN is formed. In addition, reflecting the combined state of Al and Si, the formed semiconductor thin film 102 is not polycrystalline or amorphous, but becomes a single crystal that inherits the lattice information of the single crystal silicon constituting the substrate 101. Thus, the formation of the semiconductor thin film 102 proceeds in an epitaxial growth, at least close to the epitaxial growth. In other words, the semiconductor thin film 102 may be epitaxially grown on the substrate 101.

Next, as shown in FIGS. 2D and 2E, a cap layer 103 made of Al ₂ O ₃ is formed on the semiconductor thin film 102 so as to contact the surface of the semiconductor thin film 102 and cover the semiconductor thin film 102 (second step). First, as shown in FIG. 2D, Al single atoms 202 and oxygen (O) atoms 205 are deposited in Ar plasma in the film forming chamber of the ECR plasma film forming apparatus described above. As a result, as shown in FIG. 2E, a cap layer 103 made of Al ₂ O ₃ is formed. The formed cap layer 103 also inherits the lattice information of the semiconductor thin film 102 and is formed as a crystal rather than an amorphous material.

  In the method for manufacturing a nitride semiconductor growth substrate in the above-described embodiment, the essential point is the Al monoatomic film 203 formed at the initial stage of deposition. The hydrogen termination treatment is optimal for removing and protecting the oxide film on the surface of the substrate 101 made of silicon, but the hydrogen atoms bonded to the silicon surface are not limited to room temperature, but are almost at a temperature of about 600 ° C. It cannot be removed. For this reason, if the deposition of AlN is started with hydrogen terminated, a sufficiently high quality AlN crystal cannot be obtained.

  On the other hand, when the Al monoatomic film 203 is initially formed, Al atoms are easily replaced with hydrogen on the surface of the substrate 101 due to its high activity, thereby forming a uniform Al monoatomic film 203. Is easy. In this state, the semiconductor thin film 102 made of high-quality AlN can be formed.

  Even if hydrogen atoms can be easily removed and the silicon surface can be exposed, if an AlN film is formed by supplying Al and nitrogen without forming an Al monoatomic film, so-called group III polarity is obtained. AlN having the surface and the group V polar surface on the surface side is formed at the same time, and the semiconductor thin film 102 made of high-quality AlN crystal cannot be obtained. On the other hand, by forming the Al monoatomic film 203, a uniform group III polar surface can be formed, and the semiconductor thin film 102 made of high-quality AlN can be formed. As described above, the formation of the Al monoatomic film 203 is a very important process in the above-described embodiment. Note that it is important that the Al monoatomic film 203 covers the entire surface of the substrate 101. Therefore, the Al monoatomic film 203 only needs to be formed to have a thickness that is sufficient to cover the entire area of the substrate 101. In addition, the upper limit of the thickness of the Al monoatomic film 203 is 2 monolayers.

  In the above-described embodiment, each layer is formed at room temperature (for example, 20 ° C.), but is not limited to this temperature. In the above-described embodiment, it is a so-called effect that a nitride semiconductor growth substrate can be formed even at about room temperature, and the temperature in forming each layer described above may be lower than room temperature or higher. Good.

  In the above-described embodiment, an ECR plasma film forming apparatus is used as the film forming apparatus. However, the present invention is not limited to this, and various sputtering apparatuses including a plasma-assisted chemical vapor deposition apparatus and a magnetron sputtering apparatus, Alternatively, any device can be used as long as it can appropriately form each layer described above, such as an MBE device or an MOCVD device into which oxygen is introduced.

  Next, the effect in the nitride semiconductor layer growth using the nitride semiconductor growth substrate in the embodiment of the present invention will be described. By using the nitride semiconductor growth substrate in the embodiment of the present invention, for example, as shown in FIG. 3, the AlN layer 104 and the GaN layer 105 can be formed in a high quality state. FIG. 3 is a cross-sectional view schematically showing a structure in which a nitride semiconductor layer is grown on a nitride semiconductor growth substrate of the present invention.

  Hereinafter, the formation of the AlN layer 104 and the GaN layer 105 will be described with reference to FIGS. 4A to 4D. 4A to 4D are explanatory views for explaining the formation of the nitride semiconductor layer using the nitride semiconductor growth substrate in the embodiment of the present invention. 4A to 4D schematically show states (cross sections) in each step.

  First, the substrate 101 (nitride semiconductor growth substrate) on which the semiconductor thin film 102 and the cap layer 103 are formed is loaded into the growth chamber of a well-known MOCVD apparatus, and the growth is performed in a state where hydrogen gas is supplied into the growth chamber. The indoor pressure (growth chamber pressure) is maintained at about 9806.65 Pa (0.1 atm). Next, in this state, the substrate temperature is raised to a temperature at which a nitride semiconductor such as AlN or GaN is epitaxially grown (about 1000 ° C.).

In the process of raising the substrate temperature, ammonia is introduced into the growth chamber when the substrate temperature reaches about 500 ° C. As a result, as shown in FIG. 4A, ammonia 401 is supplied to the surface of the substrate 101 (cap layer 103). Thus, the cap layer 103 is altered by being exposed to the ammonia 401 at a high temperature. A part of Al ₂ O ₃ constituting the cap layer 103 is replaced by AlN when O is replaced by N, and the cap layer 103 is not formed only by the Al ₂ O ₃ layer 131 as shown in FIG. 4B. Instead, the state changes to a state in which the AlN layers 132 are scattered in an island shape.

Next, when the substrate temperature reaches the growth temperature, as shown in FIG. 4C, in addition to ammonia 401, when trimethylaluminum (TMAl) 402 is supplied as an Al raw material, the growth of the AlN layer 104 is started. Here, the propagation of threading dislocations to the growing AlN layer 104 is inhibited by the cap layer 103 in which the AlN layer 132 is formed in an island shape in the Al ₂ O ₃ layer 131. Inhibition of the threading dislocation propagation, Al ₂ in O ₃ layer 131 Al ₂ O ₃ layer 131 itself serves as a stopper for the threading dislocation. In the AlN layer 132, the dislocation propagation direction is bent in a direction parallel to the surface of the substrate 101 due to the island shape, thereby suppressing the propagation of threading dislocations in the growth direction.

  Next, after the AlN layer 104 is grown as described above, the supply of TMAl 402 is stopped and, as shown in FIG. 4D, trimethyl gallium (TMGa) 403 is supplied as a Ga raw material, so Growth begins.

  Next, the results of evaluating the crystallinity of the GaN layer 105 fabricated as described above by X-ray diffraction will be described with reference to FIG. FIG. 5 is a characteristic diagram showing a symmetric reflection spectrum from (0002) by X-ray diffraction. In FIG. 5, (a) shows the measurement result in the GaN layer 105, and (b) shows the measurement result in the GaN layer according to the prior art. As can be seen by comparing FIGS. 5A and 5B, the GaN layer 105 formed using the nitride semiconductor growth substrate in the embodiment of the present invention has higher strength and a half-width. It is understood that high (high quality) crystallinity is obtained.

Further, when the dislocation density in GaN is estimated from the half-value width of the asymmetric reflection spectrum, the dislocation density is about 5 × 10 ¹¹ cm ^{−2 in the} conventional technique, but in the GaN layer 105, it is 4 × 10 ⁹ cm ^−2. It was about two orders of magnitude improved. The dislocation density in the GaN layer 105 is improved because the propagation of high-density threading dislocations in the semiconductor thin film 102 made of AlN on the substrate 101 is inhibited by the cap layer 103 and does not propagate to the AlN layer 104. This is because the AlN layer 104 has a low dislocation density.

  Next, an example in which a HEMT having an AlGaN / GaN heterostructure is formed on the nitride semiconductor growth substrate in the embodiment of the present invention will be described. FIG. 6 is a cross-sectional view schematically showing a state in which an AlGaN / GaN heterostructure is formed on the nitride semiconductor growth substrate of the present invention.

As shown in FIG. 6, an AlN layer 104 and a GaN layer 105 are formed on a cap layer 103 in a state composed of an Al ₂ O ₃ layer 131 and a plurality of island-like AlN layers 132, and the GaN layer 105 is formed. On top of this, an AlGaN layer 106 made of n-type AlGaAs is formed. Electrons are stored as 2DEG 151 in the GaN layer 105 close to the heterojunction interface between the GaN layer 105 and the AlGaN layer 106.

  A HEMT can be configured by forming a source electrode and a drain electrode on the AlGaN layer 106 having the AlGaN / GaN heterostructure described above and further forming a gate electrode therebetween. In this HEMT, the current flowing between the source and the drain can be controlled by changing the density of 2DEG 151 by the gate voltage.

  When this HEMT is used for high power applications, it is required that the leakage current to the substrate is small when the voltage is increased. Here, in the AlGaN / GaN heterostructure described above, as shown in FIG. 7, an electrode 701 is formed on the surface of the AlGaN layer 106, an electrode 702 is formed on the back surface of the substrate 101, and a voltage is applied between these electrodes. The current flowing at the time (= leakage current) was evaluated (measured). The measurement results are shown in FIG. FIG. 8B shows the leakage current measurement result similar to that described above for the AlGaN / GaN heterostructure according to the prior art.

As shown in FIG. 8B, the leakage current value when 200 V was applied was 65 mA / cm ² in the prior art, but as shown in FIG. It was reduced by two orders of magnitude to / cm ² . This reflects the increase in resistivity due to the low dislocations in the AlN layer grown on the nitride semiconductor growth substrate of the present invention.

As described above, according to the present invention, the cap layer made of Al ₂ O ₃ is formed on the semiconductor thin film made of AlN formed on the substrate made of a different material. With a template substrate using a substrate made of a material and AlN, an element having good characteristics using a nitride semiconductor containing Ga can be formed.

  The present invention is not limited to the embodiment described above, and many modifications and combinations can be implemented by those having ordinary knowledge in the art within the technical idea of the present invention. It is obvious. For example, in the above-described embodiment, a substrate made of single crystal silicon is used, and a semiconductor thin film made of AlN is formed thereon. However, the present invention is not limited to this. A crystal substrate such as ZnO may be used. The cap layer may be made of an oxide of Ga or In.

  DESCRIPTION OF SYMBOLS 101 ... Substrate, 102 ... Semiconductor thin film, 103 ... Cap layer.

Claims (7)

A first step of forming a semiconductor thin film made of AlN on a substrate made of a material different from a nitride semiconductor;
A second step of forming a cap layer on the semiconductor thin film in contact with the surface of the semiconductor thin film and covering the semiconductor thin film;
The method for manufacturing a nitride semiconductor growth substrate, wherein the cap layer is made of an oxide of Al, Ga, or In. In the manufacturing method of the substrate for nitride semiconductor growth according to claim 1,
The method for manufacturing a substrate for growing a nitride semiconductor, wherein the cap layer is made of Al ₂ O ₃ . The method for manufacturing a nitride semiconductor growth substrate according to claim 2,
The substrate is made of silicon;
The first step includes
Hydrogen terminating the surface of the substrate;
Forming a monolayer of Al on the surface of the hydrogen-terminated substrate;
And a step of depositing AlN on the monoatomic film and forming the semiconductor thin film in which the monoatomic film is homogenized on the deposited AlN. In the method for manufacturing a nitride semiconductor growth substrate according to claim 1 or 2,
A method for manufacturing a nitride semiconductor growth substrate, wherein the substrate is made of silicon. A substrate made of a material different from the nitride semiconductor;
A semiconductor thin film made of AlN formed on the substrate;
A cap layer formed on and in contact with the surface of the semiconductor thin film on the semiconductor thin film; and
The nitride semiconductor growth substrate, wherein the cap layer is made of an oxide of Al, Ga, or In. The nitride semiconductor growth substrate according to claim 5,
The nitride semiconductor growth substrate, wherein the cap layer is made of Al ₂ O ₃ . The nitride semiconductor growth substrate according to claim 5 or 6,
The substrate for growing a nitride semiconductor, wherein the substrate is made of silicon.