Abstract
The ultrasonic microspectroscopy (UMS) technology was applied to evaluation of 4H-SiC single crystals. We prepared six specimens with two (001)-plane substrates, two (110)-plane substrates, a (114) 7° off plane substrate, and a polyhedron block cut from crystal ingot grown by sublimation method. Significant differences between measured and published velocities of bulk waves and leaky surface acoustic waves were observed for all propagation directions and modes. Using measured bulk wave velocities, we determined elastic constants and density of this crystal exhibiting a few percent differences from the published constants. We suggested that this UMS technology had an ability to detect and evaluate the effects of the typical defects in SiC single crystals such as poly-type inclusions and micropipes.
