Systematic Investigation of 4H-SiC Trench Properties Dependence on Channel Concentration, Crystallographic Plane, and MOS Interface Treatment

摘要

We have systematically investigated the trench properties of 4H-SiC for p-type channel doping level formed by epitaxial growth, crystallographic plane, and MOS interface treatment. Our results show that the channel mobilities on the (1-100), (11-20), (-1100), and (-1-120) planes gradually decreased in the range from 1 × 10~(16) to 1 × 10~(17) cm~(-3) as the epitaxial channel concentration increased. An inevitable tradeoff existed between channel mobility (field-effect mobility, μ_(FE)) and threshold voltage in trench MOSFETs. Furthermore, the maximum μ_(FE) at a channel concentration of 1 × 10~(17) cm~(-3) was 95 cm~2·V~(-1)·s~(-1) on the (11-20) plane with wet + hydrogen (H_2) annealing, 83 cm~2·V~(-1)·s~(-1) on the (1-100) plane with wet + H_2 annealing and 57 cm~2·V~(-1)·s~(-1) on the (1-100) plane with nitric oxide annealing.