In situ etch treatment of bulk surface for epitaxial layer growth optimization
Homoepitaxial bulk 4H SiC-off-axis commercial wafers were investigated after in situ hydrogen etching on a hot wall chemical vapor deposition (HWCVD).We have performed test etching on several process conditions in order to study the surface defects reduction or transformation. A detailed map of bulk defects has been obtained by optical microscopy inspection to mark interesting position of investigated area and to identify the same area after chemical etching, with the aim to compare the defect evolution after hydrogen etching in the reactor. The highlighted defects area was analysed by means of atomic force microscopy and Micro Raman spectroscopy in order to obtain morphological and structural information. On the etched surface bulk wafer a epilayer was grown by HWCVD reactor to study the development of marked defects. The etched surfaces show a significant defect density reduction and present a good surface morphology.
etching epitaxial layer growth sic