Topographic and Reflectometric Investigation of Crystallographic Defects and Surface Roughness in 4H Silicon Carbide Homoepitaxial Layers Deposited at Various Growth Rates

Abstract

Undoped 4H silicon carbide epitaxial layers were deposited by means of CVD method with growth rates of 2 µm/h, 5 µm/h and 11 µm/h at 1540• and 0• o-cut 4H-SiC (00 · 1) substrates. The structural defects were studied before and after growth of the epitaxial layers by means of conventional Lang topography, synchrotron white beam and monochromatic beam topography and by means of X-ray specular reectometry. The topographic investigations conrmed the continuation of the dislocations in the epitaxial deposit on the 8• and 4• o-cut substrates without new extended defects. The important dierence occurred in the surface roughness of the epitaxial layers, which increased for higher growth rates. The epitaxial layers grown on 0• o-cut substrates at analogous condition contained usually other SiC polytypes, but the inuence of the growth rate on the distribution of the polytypes was observed.