Method for evaluating quality of sic single crystal body and method for producing silicon carbide single crystal ingot using the same

Patent metadata

Field	Value
Publication number	US-2020010974-A1
Application number	US-201816306129-A
Country	US
Kind code	A1
Filing date	Mar 29, 2018
Priority date	Mar 30, 2017
Publication date	Jan 9, 2020
Grant date	—

Abstract

A method for evaluating the quality of a SiC single crystal by a non-destructive and simple method; and a method for producing a SiC single crystal ingot with less dislocation and high quality with good reproducibility utilizing the same. The method for evaluating the quality of a SiC single crystal body is based on the graph of a second polynomial equation obtained by differentiating a first polynomial equation, the first polynomial equation approximating the relation between a peak shift value and a position of the measurement point and the peak shift value being obtained by an X-ray rocking curve measurement. The method for producing a SiC single crystal ingot manufactures a SiC single crystal ingot by a sublimation recrystallization method using, as a seed crystal, the SiC single crystal body evaluated by the evaluation method.

First claim

1 . A method for evaluating the quality of a SiC single crystal body composed of a disc-shaped silicon carbide single crystal,
which comprises conducting an X-ray rocking curve measurement of a main surface of the SiC single crystal body on a predetermined diffraction surface; obtaining an angle Ω at a plurality of measurement points P n on a diameter of the main surface, wherein the Ω is an angle between an X-ray incident direction and the main surface when a diffraction peak is exhibited; and calculating the difference (Ω n −Ω 0 ) as a respective peak shift value, in which Ω 0 is an angle at a certain reference measurement point P 0 and Ω n is an angle at a measurement point P n other than P 0 among these measurement points; obtaining a relation between the location of the measurement point P n (X) on the diameter of the main surface and the peak shift value (Y) as a first polynomial equation; linearly differentiating the first polynomial equation to obtain a second polynomial equation, and evaluating the quality of the SiC single crystal body based on these polynomial equations.

2 . The method for evaluating the quality of a SiC single crystal body according to claim 1 , wherein, when the second polynomial equation is expressed as a graph in which the Y axis indicates the inclination of the first polynomial equation and the X axis indicates the position of the measurement point P n on the diameter of the main surface of the SiC single crystal body, the quality is evaluated by determining whether the graph of the second polynomial equation passes Y=0 or not.

3 . The method for evaluating the quality of a SiC single crystal body according to claim 2 , wherein the quality is evaluated by determining whether a graph representing the second polynomial equation passes Y=0 twice or not.

4 . The method for evaluating the quality of a SiC single crystal body according to claim 2 , wherein the quality is evaluated by determining whether a function of a peak shift value (Y) in the first polynomial equation has an extreme value.

5 . The method for evaluating the quality of a SiC single crystal body according to claim 1 , wherein, when the second polynomial equation is expressed as a graph in which the Y axis indicates the inclination of the first polynomial equation and the X axis indicates the position of the measurement point on the diameter of the main surface of the SiC single crystal body, the quality is evaluated by a difference between a maximum value and a minimum value of the inclination (Y).

6 . The method for evaluating the quality of a SiC single crystal body according to claim 1 , wherein the degree of the first polynomial equation is 4 or more.

7 . The method for evaluating the quality of a SiC single crystal body according to claim 1 , wherein the reference measurement point P 0 is a center point of the main surface of the SiC single crystal body.

8 . The method for evaluating the quality of a SiC single crystal body according to claim 1 , wherein the dislocation of the SiC single crystal body is a basal surface dislocation.

9 . A method for producing a silicon carbide single crystal ingot in which a silicon carbide single crystal is grown on a seed crystal by a sublimation recrystallization method,
wherein an X-ray rocking curve measurement of a main surface of the SiC single crystal body composed of a disc-shaped silicon carbide single crystal is previously conducted on a predetermined diffraction surface; an angle Ω is obtained at a plurality of measurement points P n on a diameter of the main surface, wherein the Ω is an angle formed between an X-ray incident direction and the main surface when a diffraction peak is exhibited; the difference (Ω n −Ω 0 ) is calculated as a respective peak shift value, in which Ω 0 is an angle at a certain reference measurement point P 0 and Ω n is an angle at a measurement point P n other than P 0 among these measurement points; a relationship between the position of the measurement point P n (X) on the diameter of the main surface and the peak shift value (Y) is obtained as a first polynomial equation; the first polynomial equation is linearly differentiated to obtain a second polynomial equation, and when thus obtained second polynomial equation is expressed as a graph in which the Y axis indicates the inclination of the first polynomial equation and the X axis indicates the position of the measurement point P n on the diameter of the main surface of the SiC single crystal body, the SiC single crystal body whose graph does not pass Y=0 twice or more is used as a seed crystal.

Assignees

• Showa Denko Kk

Inventors

• Nakabayashi Masashi
• Ushio Shoji

Classifications

• C30B29/36

  Carbides · CPC title

• G01N23/2076

  for spectrometry, i.e. using an analysing crystal, e.g. for measuring X-ray fluorescence spectrum of a sample with wavelength-dispersion, i.e. WDXFS · CPC title

• C30B23/002 Primary

  Controlling or regulating · CPC title

• G01N2223/60

  Specific applications or type of materials · CPC title

• G01N23/207 Primary

  Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions · CPC title