Degradation in InAs–AlSb HEMTs Under Hot-Carrier Stress

InAs-AlSb high-electron mobility transistors stressed with hot carriers may exhibit shifts in the peak transconductance toward more negative gate-voltages. The devices are most degradation prone in operating conditions with high longitudinal (in the direction of IDS) electric fields in the channel. Room-temperature annealing, gate current, and channel-mobility measurements suggest the presence of a metastable defect in the top AlSb layer. Device simulations and first-principles quantum-mechanical calculations are used to investigate the physical nature of the defects responsible for degradation. Metastable configurations of substitutional and interstitial oxygen have charge states and transition energies consistent with the degradation trends.