CN-121992506-A - Gallium nitride single crystal substrate and method for producing same

Abstract

A gallium nitride single crystal substrate and a method for manufacturing the same. The subject is to maintain high thermal conductivity even in a high-temperature environment for a gallium nitride single crystal substrate. A gallium nitride single crystal substrate having a low-index crystal plane (0001) closest to a main surface, wherein R1 (H) is 80W/mk or more and 120W/mk or less, and R2 (H) is 80W/mk or more and 110W/mk or less, when R1 (H) is the thermal conductivity in the thickness direction of the main surface at 200 ℃ and R2 (H) is the thermal conductivity in the in-plane direction at 200 ℃.

Inventors

• HARUKI HIROYUKI
• SATO TAKASHI
• Kitamura Hisarang
• FUJIMOTO TETSUHIRO

Assignees

• 住友化学株式会社

Dates

Publication Date

20260508

Application Date

20251027

Priority Date

20241101

Claims (4)

1. 1. A gallium nitride single crystal substrate, which is a gallium nitride single crystal substrate having a low-index crystal plane (0001) plane nearest to a main surface, When the thermal conductivity in the thickness direction of the main surface at 200 ℃ is R1 (H) and the thermal conductivity in the in-plane direction at 200 ℃ is R2 (H), R1 (H) is 80W/mk or more and 120W/mk or less, and R2 (H) is 80W/mk or more and 110W/mk or less.
2. 2. The gallium nitride single crystal substrate according to claim 1, wherein when a thermal conductivity in a thickness direction of the main surface at 25 ℃ is R1 (L), R1 (L) is 120W/mk or more, The R1 (H) and the R1 (L) meet the requirement that (R1 (L) -R1 (H))/R1 (L) is less than or equal to 0.5.
3. 3. The gallium nitride single crystal substrate according to claim 1, wherein when the thermal conductivity in the in-plane direction at 25 ℃ is R2 (L), R2 (L) is 150W/mk or more, The R2 (H) and the R2 (L) meet the requirement that (R2 (L) -R2 (H))/R2 (L) is less than or equal to 0.6.
4. 4. A method for producing a gallium nitride single crystal substrate, comprising the steps of: (a) A step of preparing a base substrate formed of a gallium nitride single crystal having a low-index crystal plane (0001) closest to the main surface, and (B) A step of epitaxially growing a gallium nitride single crystal on the main surface of the base substrate, In the (b), a source gas for forming the gallium nitride single crystal is supplied to the base substrate under an ammonia-containing atmosphere having a growth pressure of 1atm or more and 1.5atm or less, and ammonia is supplied from the periphery of a support member that supports the base substrate.

Description

Gallium nitride single crystal substrate and method for producing same Technical Field The present invention relates to a gallium nitride single crystal substrate and a method for producing the same. Background Group III nitride semiconductors typified by gallium nitride (GaN) are widely used as materials constituting semiconductor devices such as light-emitting devices and electronic devices. In order to improve the quality (semiconductor characteristics and the like) of a semiconductor device made of a group III nitride semiconductor, it is desirable to manufacture a semiconductor laminate or a nitride semiconductor self-supporting substrate for manufacturing the semiconductor device with good crystal quality. In order to spread the generated heat, a semiconductor device may be mounted on a heat sink. A GaN single crystal substrate used in a semiconductor device is required to have high thermal conductivity from the viewpoint of improving thermal conductivity to a heat sink (for example, patent document 1). Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2008-179536 Disclosure of Invention Problems to be solved by the invention However, in an environment where a semiconductor device is actually used, the temperature may rise due to the operation of the device. On the other hand, the thermal conductivity of GaN single crystal substrates has been measured under room temperature conditions so far, and no attention has been paid to measurement under high temperature conditions. Accordingly, the present inventors have studied the thermal conductivity of gallium nitride and have found that the thermal conductivity of gallium nitride tends to decrease with an increase in temperature when the temperature is changed. Accordingly, in order for a GaN single crystal substrate used in a semiconductor device to exhibit a desired heat dissipation property even when the temperature of the semiconductor device increases, it is required to maintain a high thermal conductivity. The purpose of the present invention is to provide a technique for maintaining high thermal conductivity even in a high-temperature environment for a gallium nitride single crystal substrate. Solution for solving the problem According to one embodiment of the present invention, there is provided a gallium nitride single crystal substrate, which is a gallium nitride single crystal substrate having a low-index crystal plane (0001) plane closest to a main surface, When the thermal conductivity in the thickness direction of the main surface at 200 ℃ is R1 (H) and the thermal conductivity in the in-plane direction at 200 ℃ is R2 (H), R1 (H) is 80W/mk or more and 120W/mk or less, and R2 (H) is 80W/mk or more and 110W/mk or less. According to another aspect of the present invention, there is provided a method for producing a gallium nitride single crystal substrate, comprising: (a) A step of preparing a base substrate formed of a gallium nitride single crystal having a low-index crystal plane (0001) closest to the main surface, and (B) A step of epitaxially growing a gallium nitride single crystal on the main surface of the base substrate, In the above (b), the source gas for forming the gallium nitride single crystal is supplied to the base substrate under an ammonia-containing atmosphere having a growth pressure of 1atm or more and 1.5atm or less, and ammonia is supplied from the periphery of a support member for supporting the base substrate. ADVANTAGEOUS EFFECTS OF INVENTION According to the present invention, the gallium nitride single crystal substrate can maintain high thermal conductivity even in a high-temperature environment. Drawings Fig. 1A is a schematic cross-sectional view showing a part of a method for manufacturing a gallium nitride single crystal substrate according to an embodiment of the present invention. Fig. 1B is a schematic cross-sectional view showing a part of a method for manufacturing a gallium nitride single crystal substrate according to an embodiment of the present invention. Fig. 1C is a schematic cross-sectional view showing a part of a method for manufacturing a gallium nitride single crystal substrate according to an embodiment of the present invention. Fig. 2 is a flowchart showing a method for producing a gallium nitride single crystal substrate according to the present embodiment. Fig. 3 is a schematic configuration diagram illustrating an HVPE apparatus. Fig. 4 is a diagram showing the thermal conductivity R1 in the thickness direction at 25 ℃ and 200 ℃ for the embodiment. Fig. 5 is a diagram showing the thermal conductivity R2 in the in-plane direction at 25 ℃ and 200 ℃ for the embodiment. Description of the reference numerals 1. Gallium nitride monocrystal substrate (GaN substrate) 10. Base substrate 11. Growth layer Detailed Description < Findings obtained by the present inventors > First, an explanation will be given of findings obtained by the present inventors.