Vanadium doping using VCl 4 source during the chloro-carbon epitaxial growth of 4H-SiC

Abstract

Semi-insulating 4H-SiC epitaxial layers were produced by chloro-carbon epitaxial growth at an intermediate growth temperature of 1450 °C and at high growth temperatures of 1600 °C, enabling growth rates of 6 and in excess of 60 μm/h, respectively. Vanadium tetrachloride was used as the source of vanadium doping. In epitaxial layers otherwise dominated by nitrogen donors, vanadium-acceptor compensation mechanism was achieved, providing resistivities in excess of 10 5 Ω cm in fully compensated epilayers. Partial compensation enabled control of n-type doping in a wide range, down to around 10 14 cm −3 in epilayers with N 2 donor concentration of 1×10 15 cm −3. The domination of deep levels of vanadium was confirmed by photoluminescence spectroscopy. The limits for vanadium concentration consistent with degradation-free epilayer morphology were established to be around 1–1.5×10 17 and slightly less than 1×10 17 cm −3 for the growth at 1450 and 1600 °C, respectively.