Comparison of zincblende-phase GaN, cubic-phase SiC, and GaAs MESFETs using a fullband Monte Carlo Simulator

We present a theoretical study of metal-semiconductor field-effect transistor (MESFET) devices for three different materials: zincblende-phase gallium nitride (ZB-GaN), cubic-phase silicon carbide (3C-SiC) and gallium arsenide (GaAs). The dc breakdown voltage of comparable MESFETs made with the two wide bandgap materials, ZB-GaN and 3C-SiC are compared to that made with the well studied material, GaAs. In this way, the GaAs calculations serve as a control, enabling an accurate comparison of the device behaviors. The simulations are performed with a new, generalized, self-consistent, full-band Monte Carlo simulator. The new simulator includes fully numerical scattering rates and a fully numerical, overlap-based final-state selection process. A 0.1 (mu)m gate-length MESFET is used for all of the simulations, and rectangular wells of lightly doped material are used to model interface states. The calculated dc breakdown voltages of the ZB-GaN, 3C-SiC, and GaAs MESFETs are 18, 16, and 5 V respectively. The previously estimated factor-of-four difference between the breakdown voltage of ZB-GaN and GaAs devices is verified.