Reliability investigation of metal-semiconductor diodes in an E/D pHEMT process

Abstract

Metal-semiconductor diodes may be realized by various techniques, depending on application and processing technology. MIA-COM has recently developed an Enhancement/Depletion (EID) pHEMT process, used primarilyfor control circuits. In this process, both D-mode and E-mode FETs are configured as diodes, to serve functions such as voltage level shifting in digital logic circuits. We report here on a reliability study of E-mode FETs configured as diodes, and subjected to both high temperature and forward bias accelerated stress. Different failure modes observed during accelerated life tests of two diode configurations are discussed, and the causesfor aging are analyzed