BIAXIALLY-ORIENTED SIC COMPOSITE SUBSTRATE AND COMPOSITE SUBSTRATE FOR SEMICONDUCTOR DEVICE

摘要

A biaxially-oriented SiC composite substrate 10 comprises: a first biaxially-oriented SiC layer 20 that includes a threading screw dislocation and a basal plane dislocation; and a second biaxially-oriented SiC layer 30 that is formed continuously from the first biaxially SiC layer 20 and that contains 1×10¹⁶ atoms/cm³ - 1×10¹⁹ atoms/cm³ of a rare earth element. The defect density of the surface of the second biaxially-oriented SiC layer 30 is smaller than the defect density of the first biaxially-oriented SiC layer 20.