GaN SINGLE CRYSTAL AND METHOD FOR MANUFACTURING GaN SINGLE CRYSTAL

Patent metadata

Field	Value
Publication number	US-2017327971-A1
Application number	US-201715663276-A
Country	US
Kind code	A1
Filing date	Jul 28, 2017
Priority date	Feb 6, 2015
Publication date	Nov 16, 2017
Grant date	—

Abstract

A new GaN single crystal is provided. A GaN single crystal according to the present embodiment comprises a gallium polar surface which is a main surface on one side and a nitrogen polar surface which is a main surface on the opposite side,
wherein on the gallium polar surface is found at least one square area, an outer periphery of which is constituted by four sides each with a length of 2 mm or more, and, when the at least one square are is divided into a plurality of sub-areas each of which is a square of 100 μm×100 μm, pit-free areas account for 80% or more of the sub-areas.

First claim

1 . A method for producing a GaN single crystal, comprising the steps of:
(S1) preparing a seed comprising a nitrogen polar surface of GaN; (S2) forming a pattern mask on the nitrogen polar surface of the prepared seed, the pattern mask comprising a plurality of linear openings arranged in parallel to each other at a constant pitch; and (S3) growing GaN crystals on the nitrogen polar surface on which the pattern mask is formed, by an ammonothermal method, wherein in the step (S3), the GaN crystals grow from inside the openings of the pattern mask, then spread laterally over the pattern mask, and coalesce with each other while forming a void between the pattern mask and the crystals.

2 . The production method according to claim 1 ,
wherein in the pattern mask formed in the step (S2), an extending direction of the linear openings form an angle within a range of 12°±5° with one of intersection lines between the nitrogen polar surface of the seed and the M-planes thereof.

3 . The production method according to claim 1 ,
wherein the pattern mask is a stripe type, a rhomboid grid type, or a hexagonal grid type.

4 . The production method according to claim 1 ,
wherein the constant pitch is 4 mm or more and 20 mm or less.

5 . The production method according to claim 1 ,
wherein the size of the void in the c-axis direction is 1 mm or more.

6 . The production method according to claim 1 ,
wherein in the step (S3) mineralizer is used, and the mineralizer comprises an ammonium fluoride.

7 . The production method according to claim 6 ,
wherein the mineralizer further comprises ammonium halide selected from ammonium chloride, ammonium bromide, and ammonium iodide.

8 . A method for producing a GaN single crystal, comprising the steps of:
(S1) preparing a seed comprising a nitrogen polar surface of GaN; (S2) forming a rhomboid grid type pattern mask on the nitrogen polar surface of the prepared seed; and (S3) growing GaN crystals on the nitrogen polar surface on which the pattern mask is formed, by an ammonothermal method, wherein the rhomboid grid type pattern mask comprises a plurality of first linear openings extending along a first extending direction at a constant pitch and a plurality of second linear openings extending along a second extending direction at a constant pitch, and wherein in the step (S3), the GaN crystals grow from inside the openings of the pattern mask, then spread laterally over the pattern mask, and coalesce with each other while forming a void between the pattern mask and the crystals.

9 . The production method according to claim 8 ,
wherein the pitch between the first linear openings is 3 mm or more and 20 mm or less.

10 . The production method according to claim 9 ,
wherein the pitch between the second linear openings is 3 mm or more and 20 mm or less.

11 . The production method according to claim 8 ,
wherein, when an extending direction of one of intersection lines between the nitrogen polar surface and the M-planes of the seed is selected as a reference direction, an angle formed between the first extending direction and the reference direction is within a range of 12°±5°.

12 . The production method according to claim 11 ,
wherein an angle formed between the second extending direction and the reference direction is within a range of 72°±5°.

13 . The production method according to claim 8 ,
wherein an angle formed between the first extending direction and the second extending direction is 60°.

14 . The production method according to claim 8 ,
wherein the size of the void in the c-axis direction is 1 mm or more.

15 . The production method according to claim 8 ,
wherein in the step (S3) mineralizer is used, and the mineralizer comprises an ammonium fluoride.

16 . The production method according to claim 15 ,
wherein the mineralizer further comprises ammonium halide selected from ammonium chloride, ammonium bromide, and ammonium iodide.

17 . A method for producing a GaN single crystal, comprising the steps of:
(S1) preparing a seed comprising a nitrogen polar surface of GaN; (S2) forming a hexagonal grid type pattern mask on the nitrogen polar surface of the prepared seed; and (S3) growing GaN crystals on the nitrogen polar surface on which the pattern mask is formed, by an ammonothermal method, wherein the hexagonal grid type pattern mask comprises a plurality of first linear openings extending along a first extending direction at a constant pitch, a plurality of second linear openings extending along a second extending direction at a constant pitch, and a plurality of third linear openings extending along a third extending direction at a constant pitch, and wherein in the step (S3), the GaN crystals grow from inside the openings of the pattern mask, then spread laterally over the pattern mask, and coalesce with each other while forming a void between the pattern mask and the crystals.

18 . The production method according to claim 17 ,
wherein in the step (S3) mineralizer is used, and the mineralizer comprises an ammonium fluoride.

19 . The production method according to claim 18 ,
wherein the mineralizer further comprises ammonium halide selected from ammonium chloride, ammonium bromide, and ammonium iodide.

20 . The production method according to claim 17 ,
wherein the size of the void in the c-axis direction is 1 mm or more.

Assignees

• Mitsubishi Chem Corp

Inventors

• Fujisawa Hideo
• Mikawa Yutaka
• Kawabata Shinichiro
• Namita Hideo
• Mochizuki Tae

Classifications

• H10P14/3416

  Nitrides · CPC title

• H10P14/2921

  being crystalline insulating materials · CPC title

• H01L21/0254

  Electricity · mapped topic

• C30B29/38

  Nitrides · CPC title

• C30B25/18

  characterised by the substrate · CPC title