Method for preparing silicon carbide wafer and silicon carbide wafer

Patent metadata

Field	Value
Publication number	US-2021123843-A1
Application number	US-202016915621-A
Country	US
Kind code	A1
Filing date	Jun 29, 2020
Priority date	Oct 29, 2019
Publication date	Apr 29, 2021
Grant date	—

Abstract

A method for preparing a SiC ingot includes: disposing a raw material and a SiC seed crystal facing each other in a reactor having an internal space; subliming the raw material by controlling a temperature, a pressure, and an atmosphere of the internal space; growing the SiC ingot on the seed crystal; and collecting the SiC ingot after cooling the reactor. The wafer prepared from the ingot, which is prepared from the method, generates cracks when an impact is applied to a surface of the wafer, the impact is applied by an external impact source having mechanical energy, and a minimum value of the mechanical energy is 0.194 J to 0.475 J per unit area (cm2).

First claim

What is claimed is:

1 . A method for preparing a wafer, comprising:
disposing a raw material and a SiC seed crystal facing each other in a reactor having an internal space; subliming the raw material by controlling a temperature, a pressure, and an atmosphere of the internal space; growing the SiC ingot on the seed crystal; collecting the SiC ingot after cooling the reactor; grinding an edge of the SiC ingot; and cutting the ground SiC ingot to prepare the wafer, wherein a thermal conductivity of the reactor is 120 W/mK or less.

2 . The method of claim 1 , wherein the growing the SiC ingot on the seed crystal or the cooling the reactor is performed in an inert gas atmosphere having a flow in a direction from the raw material to the seed crystal.

3 . The method of claim 2 , wherein the growing the SiC ingot on the seed crystal is performed in the inert gas atmosphere having a flow rate of 70 sccm to 330 sccm.

4 . The method of claim 2 , wherein cooling the reactor is performed in the inert gas atmosphere having a flow rate of 1 sccm to 300 sccm.

5 . The method of claim 3 , wherein the temperature of the internal space is increased at a temperature increase rate of 1° C./min to 10° C./min.

6 . The method of claim 4 , wherein the cooling the reactor is performed at a cooling rate of 1° C./min to 10° C./min.

7 . A wafer prepared from the method of claim 1 ,
wherein when an impact is applied to a surface of the wafer, cracks are generated at the surface, wherein the impact is applied by an external impact source having mechanical energy, and wherein a minimum value of the mechanical energy is 0.194 J to 0.475 J per unit area (cm 2 ).

8 . The wafer of claim 7 , wherein an area of the surface to which the impact is applied is 100 mm 2 or less.

9 . The wafer of claim 7 , wherein the minimum value of the mechanical energy is 0.233 J to 0.475 J per unit area (cm 2 ).

10 . The wafer of claim 7 , wherein the wafer comprises a 4H-SiC structure and has a diameter of 4 inches or more.

11 . The wafer of claim 7 , wherein the impact is applied by dropping the external impact source on the surface of the wafer at a predetermined height from the surface of the wafer.

12 . The wafer of claim 7 , wherein the wafer has a micropipe (MP) density of 1.5/cm 2 or less.

13 . The wafer of claim 7 , wherein the wafer has a threading edge dislocation (TED) density of 10,000/cm 2 or less.

14 . The wafer of claim 7 , wherein the wafer has basal plane dislocation (BPD) density of 5,000/cm 2 or less.

15 . The wafer of claim 7 , wherein the thickness of the wafer is 300 μm to 600 μm.

16 . The wafer of claim 7 , wherein the wafer is substantially a single crystal 4H-SiC structure.

17 . A wafer prepared from the method of claim 1 ,
wherein the wafer has a crack-generated drop height of 100 mm or more, and wherein the crack-generated drop height is measured by a Dupont impact tester with the wafer having a thickness of 360 μm and a hammer having a weight of 25 g.

18 . The wafer of claim 17 , wherein the crack-generated drop height is measured by the Dupont impact tester with a concave die having a diameter of 4 mm.

19 . The wafer of claim 17 , wherein the crack-generated drop height is 150 mm or more.

20 . The wafer of claim 17 , wherein the wafer comprises a 4H-SiC structure and has a diameter of 4 inches or more.

Assignees

• Skc Co Ltd

Inventors

• Park Jong Hwi
• Shim Jongmin
• Yang Eun Su
• Lee Yeon Sik
• Jang Byung Kyu
• Choi Jung Woo
• Ko Sang Ki
• Ku Kap-Ryeol
• Kim Jung-Gyu

Classifications

• H10D62/8325

  Silicon carbide · CPC title

• B28D5/00

  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) · CPC title

• B24B29/02

  designed for particular workpieces · CPC title

• C30B23/02 Primary

  Epitaxial-layer growth · CPC title

• B24B9/065

  of thin, brittle parts, e.g. semiconductors, wafers · CPC title