US 12,345,660 B2
Method for evaluating crystal defects in silicon carbide single crystal wafer
Yutaka Shiga, Annaka (JP); Toru Takahashi, Annaka (JP); and Hisao Muraki, Annaka (JP)
Assigned to SHIN-ETSU HANDOTAI CO., LTD., Tokyo (JP)
Appl. No. 18/280,825
Filed by SHIN-ETSU HANDOTAI CO., LTD., Tokyo (JP)
PCT Filed Feb. 25, 2022, PCT No. PCT/JP2022/007910
§ 371(c)(1), (2) Date Sep. 7, 2023,
PCT Pub. No. WO2022/196292, PCT Pub. Date Sep. 22, 2022.
Claims priority of application No. 2021-042104 (JP), filed on Mar. 16, 2021.
Prior Publication US 2024/0142390 A1, May 2, 2024
Int. Cl. G01N 21/95 (2006.01); C30B 29/36 (2006.01); C30B 33/10 (2006.01); H01L 21/66 (2006.01)
CPC G01N 21/9505 (2013.01) [C30B 29/36 (2013.01); C30B 33/10 (2013.01); H01L 22/12 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method for evaluating crystal defects in a silicon carbide single crystal wafer, the method comprising steps of:
etching a silicon carbide single crystal wafer with melted KOH so that a size of an etch pit due to a threading edge dislocation is 10 to 50 μm;
obtaining microscopic images by automatic photographing at a plurality of positions on a surface of the silicon carbide single crystal wafer after the etching;
determining presence or absence of a defect dense part in each of all the obtained microscopic images based on a continued length of the etch pit formed by the etching; and
classifying all the obtained microscopic images into microscopic images having the defect dense part and microscopic images not having the defect dense part to evaluate a dense state of crystal defects in the silicon carbide single crystal wafer.