ESD Reliability of AlGaN/GaN HEMT Technology

This experimental study reports new aspects of electrostatic discharge (ESD) behavior in AlGaN/GaN HEMTs. The role of Schottky gate and MESA is investigated using special test structures. Influence of piezoelectric field, carrier trapping, and self-heating on ESD behavior is studied. A unique power-law-like behavior is found. Linear scaling of failure current with source-drain spacing is reported. Spot measured drain-to-source DC current is realized as an important parameter to monitor degradation. Unique degradation trends are observed for the first time and a correlation between snapback depth and % degradation is established. Cumulative nature of device degradation is discovered. Change from soft to hard failure with an increase in pulsewidth (PW) is reported. Finally, the cause of snapback instability observed in device, at low PW, is discussed.