Bias acceleration model of drain resistance degradation in InP-based HEMTs

We formulated a lifetime of InP-based HEMTs in drain resistance increase using a bias E dependence model. Several bias accelerated tests at several bias points clarified that both an electric field and current density are necessary for a resistance increase in the drain side of a device. The obtained results suggest the degradation mechanism is that hot electrons created by impact ionization ionize impurities and those impurities are extracted by gate-drain electric field. The ionized impurities result in carrier donor passivation in the n-type InAlAs region and drain resistance increase. We reduced contamination in the fabrication process and thereby achieved long-lifetime HEMTs. In-addition, in a reliability study of 40 Gbit/s InP-HEMT ICs, a low operating voltage design was adopted and lifetime of over 1×10⁶ h at 100°C was obtained.