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

A method for producing a silicon carbide single crystal ingot which comprises growing a silicon carbide single crystal on a seed crystal by a sublimation recrystallization method,

• wherein
• an X-ray rocking curve measurement of a main surface of a 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 Pn 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 Ωn−Ω0 is calculated as a respective peak shift value, in which Ω0 is an angle at a certain reference measurement point P0 and Ωn is an angle at a measurement point Pn other than P0 among these measurement points;
• a relationship between the position of the measurement point Pn (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 Pn 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 the seed crystal.