Reliability of compound semiconductor microwave field-effect devices: failure mechanisms and test methods

The outstanding development of compound semiconductor technology led to the commercial availability of GaAs MESFETs and, more recently, of MMICs and HEMTs. The most promising applications of these devices have been found in fields where high reliability is imperative, namely the military, aerospace and telecommunications area. Although MESFET failure mechanisms have been carefully investigated, many doubts are still to be removed as far as MMIC and HEMT technologies are concerned. Moreover, the design and realization of a suitable test set-up is required to safely life-test active microwave devices, due to their potential instability both during electrical characterization and life tests with bias applied and to the high temperature at which these tests are usually carried out.