Three-Dimensional Imaging of Extended Defects in 4H-SiC by Optical Second-Harmonic Generation

This paper demonstrates optical second-harmonic generation (SHG) and two-photon excited photoluminescence (2P-PL) imaging of 3C-SiC inclusions forming triangular and carrot-type defects in 4H-SiC epilayers. Triangular defects exhibit clear SHG images because 3C-SiC is SHG active, but not 4H-SiC host crystal in c-axis incidence. A carrot defect provides SHG and 2P-PL images in different regions in a basal-plane fault area. The spectrums of the SHG and 2P-PL are also investigated, and their emission mechanisms discussed.