Surface morphology of 3C-SiC heteroepitaxial layers grown by LPCVD on Si substrates

3C-SiC heteroepitaxial layers have been grown by low pressure CVD (LPCVD) method on Si substrates to develop electronic device grade epilayers. Surface morphology of these layers and cleaved surfaces were investigated by etching in molten NaOH using Nomalski microscope, SEM, and AFM. It is noted that by LPCVD method single-domain growth of 3C-SiC epilayers can be achieved even on nearly on-axis Si (001) substrates though micro-steps with several hundreds nm height are seen on the surfaces. The etch pit densities at this single domain region are estimated to be in the order of 10(4)cm(-2). This value is four order of magnitude less than that of atmospheric pressure CVD (APCVD) layers. The schematic crystallographic structures of the micro-steps and the models of lattice images of (110) plane near the steps are proposed.