Electrical current instability at gate breakdown in GaAs MESFET

The gate burnout (irreversible breakdown) of GaAs MESFET has been studied using two-dimensional (2-D) numerical simulation and experimental measurements of 10 ns pulsed gate-drain I-V characteristics, it is shown, that at some critical level of gate avalanche current the gate current instability appears. The instability results in formation of the negative differential conductivity (NDC) region on the S-shape gate-drain I-V characteristic, spatial instability of avalanche current and formation of high density current filaments. At some critical length of n/sup +/-contact regions a spatial instability results in spontaneous formation of multiple spatial-periodic filaments.