Reliability comparison of 28 V-50 V GaN-on-SiC S-band and X-band technologies

This paper discusses the reliability performance of Wolfspeed GaN/AlGaN high electron mobility transistor (HEMT) MMIC released process technologies, fabricated on 100 mm high purity semi-insulating (HPSI) 4H-SiC substrates. The intrinsic reliability performances of the 28 V and 40 V technologies, with 400 nm and 250 nm gate length, have been characterized with DC accelerated life test (DC-ALT), for which ohmic contact inter-diffusion is the wear-out mechanism, and is accelerated by temperature and current. The intrinsic reliability performance of the 50 V technologies, with 400 nm gate length, have been characterized with RF-ALT, for which source-connected second field plate void coalescence is the wear-out mechanism which is accelerated by temperature. In spite of the differences in the accelerated test methodologies and wear-out mechanisms, all of the Wolfspeed GaN-on-SiC technologies demonstrate high and similar predicted lifetimes at their respective maximum recommended operating conditions. The reliability performance is supported with successful technology qualifications with zero failures, and volume manufacturing with a demonstrated low field failure rate.