Two dimensional numerical simulation of a non-isothermal GaAs MESFET

Graduation date: 1992The low thermal conductivity of gallium arsenide compared to silicon\ud results in self-heating effects in GaAs MESFETs that limit the electrical\ud performance of such devices for high power applications. To date, analytical\ud thermal models of self heating in GaAs MESFETs are based on the assumption\ud of a uniformly heated channel. This thesis presents a two dimensional analysis\ud of the electrothermal effect of this device based on the two dimensional\ud power density distribution in the channel under various bias conditions. The\ud numerical simulation is performed using the finite difference technique. The\ud results of the simulation of an isothermal MESFET without heat effects is\ud compared with various one dimensional analytical models in the literature.\ud Electro thermal effects into the two-dimensional isothermal MESFET model\ud allowed close examination of the temperature profile within the MESFET. The\ud large gradient in power distribution results in a localized heat source within the\ud channel which increases the overall channel temperature, which shows that the\ud assumption of a uniformly heated channel is erroneous, and may lead to an\ud underestimation of the maximum channel temperature