Study of Electron Mobility in 4H-SiC Buried-Channel MOSFETs

The effects of several factors on mobility in 4H-SiC buried-channel (BC) MOSFETs are studied.A simple model that gives a quantitative analysis of series resistance effects on the effective mobility and field-effect mobility is proposed.A series resistance not only decreases field-effect mobility but also reduces the gate voltage corresponding to the peak field-effect mobility.The dependence of the peak field-effect mobility on series resistance follows a simple quadratic polynomial.The effects of uniform and exponential interface state distributions in the forbidden band on field-effect mobility are analyzed with an analytical model.The effects of non-uniform interface states can be ignored at lower gate voltages but become more obvious as the gate bias increases.