Vanadium doping using VCl4 source during the chloro-carbon epitaxial growth of 4H-SiC

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 105 Ω cm in fully compensated epilayers. Partial compensation enabled control of n-type doping in a wide range, down to around 1014 cm−3 in epilayers with N2 donor concentration of 1×1015 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 1–1.5×1017 and slightly less than 1×1017 cm−3 for the growth at 1450 and 1600 °C, respectively.