Intrinsic Defects in Annealed Unintentionally Doped Epitaxial 4H-SiC

Annealing series were performed to investigate the thermal behaviors of intrinsic defects in unintentionally doped 4H-SiC prepared by Low Pressure Chemical Vapor Deposition (LPCVD). Only one Electron Spin Resonance (ESR) peak and a wider green-yellow photoluminescence (PL) band are detected, which means the native defects consist of carbon vacancy (V_C) and complex-compounds-related V_C. The total concentration of intrinsic defects is increased and reaches its maximum at 1573 K, then decreased with elevating anneal temperature. The variety of the intrinsic defects is attributed to the process of stabilizing intrinsic defects and a strong interaction among the intrinsic defects during the annealing.