Two dimensional full band, ensemble Monte Carlo simulation of wurtzite GaN MESFETs

We performed a two-dimensional full band, ensemble Monte Carlo simulation of a GaN metal-semiconductor field effect transistor (MESFET). The substrate is the wurtzite n-GaN with a background doping density 3 × 10¹⁷cm^-3 and 0.1 μm thick. The doping concentration of both source and drain is 2 × 10¹⁹ cm^-3. Au is assumed for the gate material. The Schottky contacts are formed between Au and wurtzite GaN. The Schottky barrier height of Au/GaN is assumed to be 0.98 eV. The gate is 0.1 μm length, and the space between source and drain is 0.4 μm. The characteristics of the drain current I_d versus drain-source voltage V_DS for gate-source voltages varying from 0 to 6 V in 1 V step is obtained by Monte Carlo simulations. At V_DS = 15 V and V_GS = 0 V, The drain current I_d is 5.03 A/cm, which is higher value. The transconductance G_m, versus V_GS characteristics are also analyzed by Monte Carlo simulations. The G_m-V_GS curve is bell shaped and the maximum G_m, is 112 ms/mm at V_DS = 15 V and V_GS = 1.5 V. The current gain cutoff frequency f_T is 98 GHz at V_DS = 15 V and V_GS = 0 V.