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. (C) 2012 American Institute of Physics. [doi:10.1063/1.3678041]

Time-dependent degradation of AlGaN/GaN high electron mobility transistors under reverse bias

MENEGHINI, MATTEO;STOCCO, ANTONIO;BERTIN, MARCO;MENEGHESSO, GAUDENZIO;ZANONI, ENRICO
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. (C) 2012 American Institute of Physics. [doi:10.1063/1.3678041]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2518077
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