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

摘要

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 /spl times/ 10/sup 17/cm/sup -3/ and 0.1 /spl mu/m thick. The doping concentration of both source and drain is 2 /spl times/ 10/sup 19/ cm/sup -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 /spl mu/m length, and the space between source and drain is 0.4 /spl mu/m. The characteristics of the drain current I/sub d/ versus drain-source voltage V/sub DS/ for gate-source voltages varying from 0 to 6 V in 1 V step is obtained by Monte Carlo simulations. At V/sub DS/ = 15 V and V/sub GS/ = 0 V, The drain current I/sub d/ is 5.03 A/cm, which is higher value. The transconductance G/sub m/, versus V/sub GS/ characteristics are also analyzed by Monte Carlo simulations. The G/sub m/-V/sub GS/ curve is bell shaped and the maximum G/sub m/, is 112 ms/mm at V/sub DS/ = 15 V and V/sub GS/ = 1.5 V. The current gain cutoff frequency f/sub T/ is 98 GHz at V/sub DS/ = 15 V and V/sub GS/ = 0 V.