# US 9,435,051 B2 · Bismuth-doped semi-insulating group III nitride wafer and its production method

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,435,051 B2
- Document ID: US9435051B2
- Status: Granted
- Kind: B2
- Application number: 14/981,292
- Filed: 2015-12-28
- Published: 2016-05-12
- Granted: 2016-09-06
- Earliest claimed: 2012-08-24
- Assignees: SixPoint Materials, Inc.; Seoul Semiconductor Co., Ltd.
- Applicants: Sixpoint Materials, Inc.; Seoul Semiconductor Co., Ltd.
- Inventors: Tadao Hashimoto; Edward Letts; Sierra Hoff
- Web page: https://patentgrep.com/patent/US9435051B2

## CPC

- C30B 7/105: {using ammonia as solvent, i.e. ammonothermal processes}
- B24B 37/042: {operating processes therefor}
- B28D 5/00: Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor (working by grinding or polishing B24; for artistic purposes B44B)
- C30B 9/00: Single-crystal growth from melt solutions using molten solvents (by normal or gradient freezing C30B11/00; by zone-melting C30B13/00; by crystal pulling C30B15/00; on immersed seed crystal C30B17/00; by liquid phase epitaxial growth C30B19/00; under a protective fluid C30B27/00)
- C30B 28/04: from liquids
- C30B 29/403: {AIII-nitrides}
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10D 62/854: further characterised by the dopants
- H10D 62/86: being Group II-VI materials, e.g. ZnO
- H10P 14/2908: {Nitrides}
- H10P 90/123: {by grinding or lapping}
- 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
- B24B: MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING (grinding of gear teeth B23F, of screw-threads B23G1/36; by electro-erosion B23H; abrasive or related blasting B24C; tools for grinding, buffing or sharpening B24D; polishing compositions C09G1/00; abrasives C09K3/14; electrolytic etching or polishing C25F3/00; grinding arrangements for use on assembled railway tracks E01B31/17); DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B28D: WORKING STONE OR STONE-LIKE MATERIALS
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The present invention discloses a semi-insulating wafer of GaxAlyIn1-x-yN (0≦x≦1, 0≦x+y≦1) which is doped with bismuth (Bi). The semi-insulating wafer has the resistivity of 104 ohm-cm or more. Although it is very difficult to obtain a single crystal ingot of group III nitride, the ammonothermal method can grow highly-oriented poly or single crystal ingot of group III nitride having the density of dislocations/grain boundaries less than 105 cm−2. The invention also disclose the method of fabricating the semi-insulating group III nitride bulk crystals and wafers.

## Claims

### Claim 1

A method of growing a bismuth doped group III nitride bulk crystal having a surface area greater than 10 mm2 and thickness greater than 200 microns comprising:
a. placing a group III containing nutrient in a high-pressure reactor;
b. placing a mineralizer in the high-pressure reactor;
c. placing at least one seed crystal in the high-pressure reactor;
d. placing a bismuth-containing dopant in the high-pressure reactor;
e. placing ammonia in the high-pressure reactor;
f. sealing the high-pressure reactor;
g. providing sufficient heat to the ammonia to create a supercritical state of ammonia; and
h. crystallizing group III nitride on the seed crystal, wherein a sufficient amount of the bismuth-containing dopant is present such that the crystallized group III nitride is semi-insulating.

### Claim 2 (depends on 1)

The method according to claim 1 wherein the bismuth-containing dopant is selected from metallic bismuth and bismuth doped group III nitride.

### Claim 3 (depends on 2)

The method according to claim 2 wherein the group III nitride crystallized on the seed crystal is GaN.

### Claim 4 (depends on 3)

The method according to claim 3 wherein the crystallized group III nitride has a dislocation density less than 105 cm−2.

### Claim 5 (depends on 1)

The method according to claim 1 wherein the group III nitride crystallized on the seed crystal is GaN.

### Claim 6 (depends on 5)

The method according to claim 5 wherein the crystallized group III nitride has a dislocation density less than 105 cm−2.

### Claim 7 (depends on 1)

The method according to claim 1 wherein the crystallized group III nitride has a dislocation density less than 105 cm−2.

### Claim 8 (depends on 1)

The method according to claim 1 wherein the seed crystal is GaN.

### Claim 9 (depends on 1)

The method according to claim 1 wherein the mineralizer contains alkali metal.

### Claim 10 (depends on 1)

The method according to claim 1 wherein the mineralizer contains sodium.

### Claim 11 (depends on 1)

The method according to claim 1 wherein the growth temperature is between 500 and 600° C.

### Claim 12 (depends on 1)

The method according to claim 1 wherein the seed crystal is a c-plane seed crystal.

### Claim 13 (depends on 1)

The method according to claim 1 wherein the crystallized group III nitride has a thickness of more than 200 microns.

### Claim 14 (depends on 1)

The method according to claim 1 wherein the crystallized group III nitride has a resistivity of 104 ohm-cm or higher.

### Claim 15 (depends on 1)

The method according to claim 1 wherein the crystallized group III nitride has an optical absorption coefficient higher than 10 cm−1 throughout the visible wavelength range.

### Claim 16 (depends on 1)

A method of fabricating a bismuth doped group III nitride semi-insulating wafer comprising slicing the bismuth doped group III nitride hulk crystal formed by the method of claim 1 to form a wafer.

### Claim 17 (depends on 16)

The method according to claim 16 and further comprising polishing a surface of the wafer on Which a device is to he fabricated.