Effect of high gate current density and temperature stress on performance of GaAs MESFETs with TiAl and TiPtAu gate

Effect of high gate current density and temperature stress on performance of GaAs MESFETs with TiAl and TiPtAu Gate is presented. Experimental results show that (1). The TiAl gate Schottky diode characteristics (gate series resistance R_g, ideality factor n, barrier height Φ_b) degrades rapidly whereas the device parameters such as maximum drain saturation current I_dss, open channel resistance R_g, below the gate, pinch-off-voltage V_p0 etc., remain fairly unchanged; (2) for TiPtAu gate MESFET, for suitable annealing, the Schottky diode characteristics (ideality factor n, barrier height Φ_b) remains stable whereas the device parameters such as maximum drain saturation current I _dss, open channel resistance below the gate R_g, pinch-off-voltage V_p0, the transconductance g_m etc. degrade rapidly; (3) the increase in gate series resistance R_g is a the main factor that leads to increase in ideality factor n of TiAl and TiPtAu gate Schottky diodes. The parameter degradation of the two types of MESFETS is different