Comparison between Polishing Etching of On and Off-Axis C and Si-Faces of 4H-SiC Wafers
Crystallographic quality of the epitaxial layers depends on the process temperature, partial pressures of active components and the surface polarity and also on the crystallographic quality of the subsurface layer resulting from the preparation of the substrate. The polishing etching in hydrogen-propane atmosphere of 4H-SiC substrate of different orientations and polarity was studied. The optimization of the polishing etching has been achieved with respect to the flow of C3H8, the duration and the temperature of the process. The investigation of the surface of SiC substrate before and after in situ polishing-etching in H2+C3H8 atmosphere was carried out by Nomarski interference contrast microscopy (DIC) and atomic force microscope (AFM).
Amador Pérez-Tomás, Philippe Godignon, Miquel Vellvehí and Pierre Brosselard
K. Kościewicz et al., "Comparison between Polishing Etching of On and Off-Axis C and Si-Faces of 4H-SiC Wafers", Materials Science Forum, Vols. 615-617, pp. 597-600, 2009