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/sub g/, ideality factor n, barrier height /spl Phi//sub b/) degrades rapidly whereas the device parameters such as maximum drain saturation current I/sub dss/, open channel resistance R/sub g/, below the gate, pinch-off-voltage V/sub p0/ etc., remain fairly unchanged; (2) for TiPtAu gate MESFET, for suitable annealing, the Schottky diode characteristics (ideality factor n, barrier height /spl Phi//sub b/) remains stable whereas the device parameters such as maximum drain saturation current I/sub dss/, open channel resistance below the gate R/sub g/, pinch-off-voltage V/sub p0/, the transconductance g/sub m/ etc. degrade rapidly; (3) the increase in gate series resistance R/sub 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.