Reliability investigation and characterization of failure modes in Schottky diodes

Schottky diodes may be realized by various techniques, depending on application and processing technology. M/A-COM has recently developed an enhancement/depletion (E/D) pHEMT process, used primarily for control circuits around its mature RF circuitry. We report here a reliability study of two diodes (configured using E-FETs), subjected to both high temperature and forward bias accelerated stress. Different failure modes observed during accelerated life tests of the two diode configurations are discussed, and the causes for aging are analyzed. Results of the stress test are backed by equivalent circuit modeling using ADS™. The differences in the effect of these failure modes on circuit performance are discussed.