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

摘要

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 x 10(20) 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). (C) 2019 The Japan Society of Applied Physics