Transition of conduction mechanism from band to variable-range hopping conduction due to Al doping in heavily Al-doped 4H-SiC epilayers

Abstract

Abstract We investigate the transition of the conduction mechanism from band and nearest-neighbor hopping (NNH) conduction to variable-range hopping (VRH) conduction in heavily Al-doped 4H-SiC epilayers with increasing Al concentration (C Al). In a sample with C Al of 1.8 × 1020 cm−3, the dominant conduction mechanisms at high and low temperatures were band and VRH conduction, respectively, whereas in samples with lower C Al values they were band and NNH conduction, respectively, and in samples with higher C Al values VRH conduction was dominant over the entire range of measurement temperatures examined (20–600 K).