Silicon carbide wafer and method of forming the same

Patent metadata

Field	Value
Publication number	US-12466019-B2
Application number	US-202519008639-A
Country	US
Kind code	B2
Filing date	Jan 3, 2025
Priority date	Jan 10, 2024
Publication date	Nov 11, 2025
Grant date	Nov 11, 2025

Abstract

A silicon carbide wafer having a seed end and a dome end opposite to the seed end. In the silicon carbide wafer, a basal plane dislocation (BPD) density detected by potassium hydroxide (KOH) etching is less than 550 pcs/cm 2 at both the seed end and the dome end, and a basal plane dislocation (PL-BPD) density detected by photoluminescence is less than 2000 pcs/cm 2 at both the seed end and the dome end.

First claim

What is claimed is:

1 . A silicon carbide wafer, having a seed end and a dome end opposite to the seed end, wherein
a basal plane dislocation (BPD) density detected by potassium hydroxide (KOH) etching is less than 550 pcs/cm 2 at both the seed end and the dome end, and a basal plane dislocation (PL-BPD) density detected by photoluminescence is less than 2000 pcs/cm 2 at both the seed end and the dome end.

2 . The silicon carbide wafer according to claim 1 , wherein for the basal plane dislocation (BPD) density detected by potassium hydroxide (KOH) etching, a difference ratio D of a first base plane dislocation density BPD1 at the seed end to a second base plane dislocation density BPD2 at the dome end is required to satisfy the following equation (1):

D
=

(

BPD
⁢
1

-

BPD
⁢
2

)

/
BPD
⁢
1

≤

26
⁢

%
.

(
1
)

3 . The silicon carbide wafer according to claim 1 , wherein for the basal plane dislocation (PL-BPD) density detected by photoluminescence, a difference ratio PL-D of a first base plane dislocation density PL-BPD1 at the seed end to a second base plane dislocation density PL-BPD2 at the dome end is required to satisfy the following equation (2):

PL
-
D

=

(

PL
-

BPD
⁢
1

-
PL
-

BPD
⁢
2

)

/
PL

-

BPD
⁢
1

≤

16
⁢

%
.

(
2
)

4 . The silicon carbide wafer according to claim 3 , wherein the difference ratio PL-D of the first base plane dislocation density PL-BPD1 at the seed end to the second base plane dislocation density PL-BPD2 at the dorm end is 14% or less.

5 . The silicon carbide wafer according to claim 3 , wherein the difference ratio PL-D of the first base plane dislocation density PL-BPD1 at the seed end to the second base plane dislocation density PL-BPD2 at the dorm end is 12% or less.

6 . The silicon carbide wafer according to claim 3 , wherein the difference ratio PL-D of the first base plane dislocation density PL-BPD1 at the seed end to the second base plane dislocation density PL-BPD2 at the dorm end is 10% or less.

7 . The silicon carbide wafer according to claim 1 , wherein the basal plane dislocation (BPD) density detected by the potassium hydroxide (KOH) etching is less than 200 pcs/cm 2 at both the seed end and the dome.

8 . The silicon carbide wafer according to claim 1 , wherein the basal plane dislocation (PL-BPD) density detected by the photoluminescence is less than 1000 pcs/cm 2 at both the seed end and the dome end.

9 . The silicon carbide wafer according to claim 1 , wherein a wafer diameter of the silicon carbide wafer is 150 mm, 200 mm, or 300 mm.

10 . The silicon carbide wafer according to claim 1 , wherein the silicon carbide wafer has a through-spiral dislocation (TSD) density of 5 pcs/cm 2 or less, a bar stacking fault (BSF) density of 5 pcs/wafer or less, and a stacking fault (SF) density of 5 pcs/wafer or less.

11 . The silicon carbide wafer according to claim 1 , wherein a warp of the silicon carbide wafer is less than 40 μm, a bow is within a range of +/−20 μm, and a triangle defect density is less than 0.1 pcs/cm 2 .

12 . A method of forming a silicon carbide wafer, comprising:
providing a raw material containing a carbon element and a silicon element and a seed crystal located above the raw material in a reactor; performing a growth process of silicon carbide crystal, wherein the growth process comprises heating the reactor and the raw material to form a silicon carbide crystal on the seed crystal, in the growth process, controlling an axial temperature gradient (ΔTz) of the silicon carbide crystal in a range of 20° C./cm to 150° C./cm, and controlling a radial temperature gradient (ΔTx) of the silicon carbide crystal in a range of 10° C./cm to 100° C./cm; and after slicing and polishing the silicon carbide crystal, obtaining a silicon carbide wafer.

13 . The method according to claim 12 , wherein in the growth process, the axial temperature gradient (ΔTz) of the silicon carbide crystal is controlled to be in a range of 20° C./cm to 100° C./cm, and the radial temperature gradient (ΔTx) of the silicon carbide crystal is controlled to be in a range of 10° C./cm to 80° C./cm.

14 . The method according to claim 12 , wherein a temperature gradient difference (ΔTz−ΔTx) between the axial temperature gradient and the radial temperature gradient of the silicon carbide crystal is in a range of 10° C./cm to 50° C./cm.

Assignees

• Globalwafers Co Ltd

Inventors

• Lin Ching-Shan

Classifications

• H10P90/123 Primary

  by grinding or lapping · CPC title

• H10P90/129

  by polishing · CPC title

• B32B3/00

  Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form · CPC title

• C30B33/00

  After-treatment of single crystals or homogeneous polycrystalline material with defined structure (C30B31/00 takes precedence) · CPC title

• C30B23/02

  Epitaxial-layer growth · CPC title