Identification of the Structures and Sources of Shockley-Type In-Grown Stacking Faults in 4H-SiC Epilayers

Shockley-type in-grown stacking faults (IGSFs) in 4H-SiC epilayers are studied. Most of the IGSFs are observed to be of triangular shape in the samples. Detailed optical features of two types of IGSFs are revealed by room temperature cathodoluminescence (RTCL) and low-temperature photoluminescence (LTPL). Energy gaps (E-gx) of the two types of IGSFs are deduced to be 2.511 and 2.764eV from their emission wavelengths. They are identified to be of (6, 2) and (4, 4) types, respectively. The nucleation sites and propagation of the IGSFs are tracked by back etching and defect-selective-etching (DSE), and threading screw dislocations (TSDs) are frequently observed at the nucleation sites of the Shockley-type IGSFs. The nucleation mechanism of these IGSFs is discussed, and the TSDs are suggested to be the major sources of the IGSFs.