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

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 ( V th ) 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.