This paper demonstrates that when InGaN LEDs are submitted to a constant reverse bias, they can show a time-dependent breakdown, that leads to the catastrophic failure of the devices. By submitting green and blue LEDs to constant voltage stress in the range between -40 V and -60 V we demonstrate that: (i) under reverse bias conditions, current is focused on localized paths, whose positions can be identified by electroluminescence measurements, and that originate from the presence of extended defects; (ii) during a constant voltage stress, the reverse current of the LEDs gradually increases; (iii) for longer stress times, all devices show a time-dependent breakdown; (iv) time-to-failure has an exponential dependence on stress voltage, and is Weibull-distributed.

Investigation of the time-dependent failure of InGaN-based LEDs submitted to reverse-bias stress

De Santi, Carlo;Meneghini, Matteo;Renso, Nicola;Buffolo, Matteo;Trivellin, Nicola;Meneghesso, Gaudenzio;Zanoni, Enrico
2017

Abstract

This paper demonstrates that when InGaN LEDs are submitted to a constant reverse bias, they can show a time-dependent breakdown, that leads to the catastrophic failure of the devices. By submitting green and blue LEDs to constant voltage stress in the range between -40 V and -60 V we demonstrate that: (i) under reverse bias conditions, current is focused on localized paths, whose positions can be identified by electroluminescence measurements, and that originate from the presence of extended defects; (ii) during a constant voltage stress, the reverse current of the LEDs gradually increases; (iii) for longer stress times, all devices show a time-dependent breakdown; (iv) time-to-failure has an exponential dependence on stress voltage, and is Weibull-distributed.
Proceedings of SPIE - The International Society for Optical Engineering
9781510606890
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11577/3251074
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