# US 2026/0193809 A1 · Method for producing aln single crystal substrate and aln single crystal substrate

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- Number: US 2026/0193809 A1
- Document ID: US20260193809A1
- Status: Published application
- Kind: A1
- Application number: 19/557,227
- Filed: 2026-03-05
- Published: 2026-07-09
- Earliest claimed: 2023-09-06
- Assignees: NGK Insulators, Ltd.
- Applicants: Ngk Insulators, Ltd.
- Inventors: Kyohei ATSUJI; Hiroharu KOBAYASHI; Yosuke SATO
- Web page: https://patentgrep.com/patent/US20260193809A1

## CPC

- C30B 1/02: by thermal treatment, e.g. strain annealing (C30B1/12 takes precedence)
- C30B 1/12: by pressure treatment during the growth
- C30B 29/403: {AIII-nitrides}
- C30B 23/00: Single-crystal growth by condensing evaporated or sublimed materials
- C30B 33/06: Joining of crystals
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR

## Abstract

There is provided a method for producing an AlN single crystal substrate including the steps of providing an AlN bonded body composed of an AlN seed crystal and an AlN sintered body; and subjecting the AlN bonded body to a heat treatment to grow an AlN single crystal from the AlN seed crystal.

## Claims

### Claim 1

A method for producing an AlN single crystal substrate, comprising the steps of:
providing an AlN bonded body composed of an AlN seed crystal and an AlN sintered body; and
subjecting the AlN bonded body to a heat treatment to grow an AlN single crystal from the AlN seed crystal.

### Claim 2 (depends on 1)

The method for producing an AlN single crystal substrate according to claim 1, wherein the AlN sintered body is provided by a method comprising the steps of:
(a1) mixing an AlN powder and a powder containing at least one rare earth element to prepare a mixed powder having an AlN content of 95% by weight or more;
(a2) shaping the mixed powder into a predetermined shape to prepare a green body, and
(a3) firing the green body to prepare an AlN sintered body with an average crystal grain size of 1 to 40 μm.

### Claim 3 (depends on 1)

The method for producing an AlN single crystal substrate according to claim 1, wherein the step of growing an AlN single crystal from the AlN seed crystal comprises growing an AlN single crystal over an entire region of the AlN sintered body.

### Claim 4 (depends on 1)

An AlN single crystal substrate produced by the method according to claim 1.

### Claim 5 (depends on 4)

The AlN single crystal substrate according to claim 4, wherein the AlN single crystal substrate has a size with a diameter of 100 mm or more.

### Claim 6 (depends on 4)

The AlN single crystal substrate according to claim 4, wherein an X-ray rocking curve full width at half maximum of a (002) plane of the AlN single crystal on at least one surface of the AlN single crystal substrate is 20 to 350 arcsec.

### Claim 7 (depends on 4)

The AlN single crystal substrate according to claim 4, wherein an X-ray rocking curve full width at half maximum of a (102) plane of the AlN single crystal on at least one surface of the AlN single crystal substrate is 20 to 500 arcsec.

### Claim 8 (depends on 4)

The AlN single crystal substrate according to claim 4, wherein at least one surface of the AlN single crystal substrate has a defect density of 1.0×103 to 1.0×107 cm−2.

### Claim 9 (depends on 4)

A device comprising the AlN single crystal substrate according to claim 4.