Unique ESD behavior and failure modes of AlGaN/GaN HEMTs

Abstract

Present experimental study reports various failure modes under ESD stress conditions and distinct ESD behavior of AlGaN/GaN HEMTs for the first time. Effect of MESA isolation and gate finger on the ESD behavior of HEMTs is analyzed. Effect of pulse width on ESD robustness and snapback voltage is observed and a unique power law like behavior is found. Cumulative nature of device degradation under ESD stress condition is discovered. Correlation between depth of snapback and failure threshold with % device degradation is found. Finally, impact of inverse piezoelectric effect in AlGaN/GaN system, fringing electric field, role of contact resistivity, temperature and field induced contact metal migration and premature breakdown of parasitic MESA Schottky junction are studied in context to AlGaN/GaN HEMT failure ESD conditions.