Analysis on Generation of Localized Step-Bunchings on 4H-SiC(0001)Si Face by Synchrotron X-Ray Topography

Abstract

Surface roughening regions running like scratches are often observed locally after epitaxy film grown on a very flat 4H-SiC wafer surfaces. We investigated generation mechanism of such roughening surface by using X-ray topography and confocal optical microscopy. We found that lattice defects were often introduced during CMP at local regions, and those local regions cannot be recognized by optical microscopy, since very flat surface can be observed. By H2 etching which is preprocess of epitaxy film growth, those lattice defects are almost etched off, but local rough surface consists of pits and step bunching regions appear like scratches, and those local pits and surface roughening regions grew up to step bunching during epitaxy film growth.