Drain current limitations and temperature effects in GaAs MESFETs

The maximum drain current and the corresponding knee voltage that play an important role in determining the maximum power handling capability of a GaAs MESFET are defined in a practical manner. Simple and yet accurate enough expressions are derived for them in terms of device geometrical and material parameters. The relationship between the maximum and zero-gate-bias drain currents is also presented. Theoretical values of dc parameters are in excellent agreement with their measured values. Important findings on the temperature dependence of these parameters are also shown.