Reliability characteristics of pHEMT resulting from electron interaction with interface states under the gate

The hot electron degradation of pHEMT devices was compared in this study with recent results of stress testing of MESFETs. The off-state (two terminal) stress condition caused failures in pHEMT transistors, as was the case with two terminal stress of MESFETs. The three-terminal stress of pHEMTs led also to hot electron degradation, while similar stress did not affect the performance of MESFETs. The significant difference in the reliability of these two groups of devices is linked to interaction of electron flow in the channel with interface states in the transistor structure.