Hydrogen etching influence on 4H-SiC homo-epitaxial layer for high power device

The surface preparation of 4H-SiC substrate plays a crucial role for the epitaxial growth. In the present work, the Hydrogen etching influence on 4H-SiC surface of substrate before the growth process was studied. The epi-layer was grown with a commercial low-pressure, hot-wall Chemical Vapor Deposition (CVD) reactor by Tokyo Electron Limited. The etching time of the surface was increased until three time (x3) respect with the value (x1) usually adopted for the growth. Photoluminescence and optical inspection analyses show a clear relationship between the etching time and the defectivity (stacking faults, carrots, comets, triangles and pits). Atomic Force Microscope (AFM) measurements also show an increase of step bunching with the etching time.