Cross-sectional observation of stacking faults in 4H-SiC by KOH etching on nonpolar face, cathodoluminescence imaging, and transmission electron microscopy

Abstract

To evaluate the evolution of stacking faults (SFs) in 4H-SiC along the c-axis growth direction, techniques that can be used to determine the precise position of SFs and their fault types from cross-sectional nonpolar faces are urgently required. In this research, we have studied the feasibility of using cathodoluminescence (CL) imaging and face molten KOH etching to obtain information on the SF density and SF types. Particular attention has been paid to the possibility of determining the stacking sequence of SFs using their CL signatures or the geometrical properties of their KOH etch figures. Transmission electron microscopy (TEM) has been employed to clarify the atomic arrangement of SFs beneath the KOH etch figures, and a model is proposed to explain the formation of linear etch patterns during KOH etching due to the existence of SFs.