Bismuth-doped semi-insulating group iii nitride wafer and its production method

Patent metadata

Field	Value
Publication number	US-2016130720-A1
Application number	US-201514981292-A
Country	US
Kind code	A1
Filing date	Dec 28, 2015
Priority date	Apr 7, 2006
Publication date	May 12, 2016
Grant date	—

Abstract

The present invention discloses a semi-insulating wafer of Ga x Al y In 1-x-y N (0≦x≦1, 0≦x+y≦1) which is doped with bismuth (Bi). The semi-insulating wafer has the resistivity of 10 4 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 10 5 cm −2 . The invention also disclose the method of fabricating the semi-insulating group III nitride bulk crystals and wafers.

First claim

What is claimed is:

1 . A method of growing a bismuth doped group III nitride bulk crystal having a surface area greater than 10 mm 2 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.

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

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

4 . A method according to claim 3 wherein the crystallized group III nitride has a dislocation density less than 10 5 cm −2 .

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

6 . A method according to claim 5 wherein the crystallized group III nitride has a dislocation density less than 10 5 cm −2 .

7 . A method according to claim 1 wherein the crystallized group III nitride has a dislocation density less than 10 5 cm −2 .

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

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

10 . A method according to claim 1 wherein the mineralizer contains sodium.

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

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

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

14 . A method according to claim 1 wherein the crystallized group III nitride has a resistivity of 10 4 ohm-cm or higher.

15 . A 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.

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

17 . A method according to claim 16 and further comprising polishing a surface of the wafer on which a device is to be fabricated.

Assignees

• Sixpoint Materials Inc
• Seoul Semiconductor Co Ltd

Inventors

• Hashimoto Tadao
• Letts Edward
• Hoff Sierra

Classifications

• H10P90/123

  by grinding or lapping · CPC title

• H10P14/2908

  Nitrides · CPC title

• C30B7/105 Primary

  using ammonia as solvent, i.e. ammonothermal processes · CPC title

• B24B37/042

  operating processes therefor · CPC title

• C30B29/403

  AIII-nitrides · CPC title