This paper describes a detailed analysis of the time-dependent degradation kinetics of GaN-based high electron mobility transistors submitted to reverse-bias stress. We show that: (1) exposure to reverse-bias may induce recoverable changes in gate leakage and threshold voltage, due to the accumulation of negative charge within the AlGaN layer, and of positive charge at the AlGaN/GaN interface. (2) Permanent degradation consists in the generation of parasitic leakage paths. Several findings support the hypothesis that permanent degradation is due to a defect percolation process: (2(a)) for sufficiently long stress times, degradation occurs even below the “critical voltage” estimated by step stress experiments; (2(b)) before permanent degradation, gate current becomes noisy, indicating an increase in defect concentration; and (2(c)) time to breakdown strongly depends on the initial defectiveness of the samples.
Time-dependent degradation of AlGaN/GaN high electron mobility transistors under reverse bias / Meneghini, M.; Stocco, A.; Bertin, M.; Marcon, D.; Chini, Alessandro; Meneghesso, G.; Zanoni, E.. - In: APPLIED PHYSICS LETTERS. - ISSN 1077-3118. - STAMPA. - 100:3(2012), pp. 033505-1-033505-3. [10.1063/1.3678041]
Time-dependent degradation of AlGaN/GaN high electron mobility transistors under reverse bias
CHINI, Alessandro;
2012
Abstract
This paper describes a detailed analysis of the time-dependent degradation kinetics of GaN-based high electron mobility transistors submitted to reverse-bias stress. We show that: (1) exposure to reverse-bias may induce recoverable changes in gate leakage and threshold voltage, due to the accumulation of negative charge within the AlGaN layer, and of positive charge at the AlGaN/GaN interface. (2) Permanent degradation consists in the generation of parasitic leakage paths. Several findings support the hypothesis that permanent degradation is due to a defect percolation process: (2(a)) for sufficiently long stress times, degradation occurs even below the “critical voltage” estimated by step stress experiments; (2(b)) before permanent degradation, gate current becomes noisy, indicating an increase in defect concentration; and (2(c)) time to breakdown strongly depends on the initial defectiveness of the samples.Pubblicazioni consigliate
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