Abstract

A fully physical electro-thermal model is described. I combines he fast, quasi-2-dimensional Leeds Physical Model of MESFETs and HEMTs, with the compact Leeds thermal impedance ma rix model of time-dependent heat flow in complex 3-dimensional systems.The coupled electro-thermal model is applied o the design optimisation of multigate power FETs. In particular,he possibility of reducing emperature variation between gate fingers by non uniform spacing is examined. The implications for improved efficiency, and for possible reduction of thermal intermodulation distortion and improvement of reliability are discussed. The model is validated experimentally by comparison of simulated results agains infrared thermal images of power FETs.