A new degradation mechanism of PM-HEMT's subsequent to hot electron stress tests or high temperature storage tests is presented. A noticeable increase in drain-to-source current, I DS, is observed after the tests. We show that this I DS variation is slowly recoverable and is correlated with the presence of deep levels in the device. Stress tests cause a variation of trapped charge. Trapping of holes created by impact-ionization and/or thermally stimulated electron detrapping induce a variation of the net negative trapped charge, leading to a decrease in the threshold voltage, V T and a consequent increase in I DS. The correlation between g mΔV T and ΔI DS clearly demonstrates that the variation of trapped charge induced by hot electron teste is localized under the gate.
Trapped charge modulation: a new cause of instability in AlGaAs/InGaAs/GaAs pseudomorphic HEMT’s / Meneghesso, G; Canali, C; Cova, Paolo; DE BORTOLI, E; Zanoni, E.. - In: IEEE ELECTRON DEVICE LETTERS. - ISSN 0741-3106. - 17:(1996), pp. 232-234. [10.1109/55.491839]
Trapped charge modulation: a new cause of instability in AlGaAs/InGaAs/GaAs pseudomorphic HEMT’s
COVA, Paolo;
1996-01-01
Abstract
A new degradation mechanism of PM-HEMT's subsequent to hot electron stress tests or high temperature storage tests is presented. A noticeable increase in drain-to-source current, I DS, is observed after the tests. We show that this I DS variation is slowly recoverable and is correlated with the presence of deep levels in the device. Stress tests cause a variation of trapped charge. Trapping of holes created by impact-ionization and/or thermally stimulated electron detrapping induce a variation of the net negative trapped charge, leading to a decrease in the threshold voltage, V T and a consequent increase in I DS. The correlation between g mΔV T and ΔI DS clearly demonstrates that the variation of trapped charge induced by hot electron teste is localized under the gate.File | Dimensione | Formato | |
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