Optimising the Rectification Ratio of Schottky Diodes in N-Sic and N-Si by TCAD

Finite element modelling has been used to optimise the current/ voltage (I/V) characteristics of metal/ n-SiC and metal/ n-Si diodes incorporating a thin interfacial layer. The electrical properties of the diodes have been examined in relation to the polytype of SiC (3H, 4H or 6C), the doping level, N A , (10 15 - 10 18 cm 3 ) of the substrate, the defect state density, D it and the work function of the Schottky metal, F m . The modelling by Technology Computer-Aided Design (TCAD) has shown that the presence of an interfacial insulating layer with a thickness of 1.0 nm has reduced the reverse leakage current of the diode by a factor of ~10 2 in Si and 10 13 (from 10 -19 A to 10 -6 A) for SiC with only a minor reduction (~ 0.8 times) in the forward current in SiC. The properties of the diodes have been modelled at room temperature without thermal annealing.