Simulation study of GaN n-MOSFETs by two-dimensional full band Monte Carlo approach

Electrical properties of GaN n-MOSFET are presented by simulation study using the two-dimensional full band Monte Carlo approach. The band structure was calculated by the first-principle total-energy pseudopotential method within local-density-functional formalism. The various scatterings, such as polar optical scattering, impurity scattering, acoustic phonon scattering, and intervalley scattering, were included in the simulation. The vertical structure of the GaN n-MOSFET is Au/SiO2 (50 nm)/GaN with the channel of 300 nm length. The simulation results showed that the device is normally off with a threshold voltage of about +3.0 V. IDS is about 4.96 A/cm at VDS=15 V and VGS=5 V. The maximum transconductance is about 0.44 S/cm at VGS=13.75 V and VDS=12 V. The maximum current gain cutoff frequency fT is about 86 GHz at VGS=8.75 V and IDS=2 A/cm.