A parametric technique for trap characterization in AlGaN/GaN HEMTs

International audienceA new parametric and cost-effective technique is developed to decouple the mechanisms behind current degradation in AlGaN/GaN high-electron mobility transistors (HEMTs) under a normal device operation: self-heating and charge trapping. Our unique approach investigates charge trapping using both source (IS) and drain (ID) transient currents for the first time. Two types of charge-trapping mechanisms are identified: 1) bulk charge trapping occurring on a timescale of less than 1 ms and 2) surface charge trapping with a time constant larger than a millisecond. Through monitoring the difference between IS and ID, a bulk charge-trapping time constant is found to be independent of both drain (V DS ) and gate (V GS ) biases. Surface charge trapping is found to have a much greater impact on slow degradation than bulk trapping and self-heating. At a short timescale (1 ms), the dynamic ON-resistance degradation is predominantly limited by surface charge trapping