The optical properties of blue InGaN-based light-emitting diodes aged at high current levels have been studied by electroluminescence and cathodoluminescence. The onset of a broad optical band peaked at about 3.1 eV in devices aged without a heat sink ~junction temperature higher than 300 °C! has been correlated to an electrothermal threshold effect. The band is attributed to the dissociation of Mg–H complexes inside the p-type layers and to the consequent formation of Mg-related metastable complexes acting as acceptors. Subsequent electron-beam irradiation determines the almost complete quenching of the band

This work presents the results of an extensive DC current aging and failure analysis carried out on blue InGaN/GaN LEDs which identify failure mechanisms related to package degradation, changes in effective doping profile, and generation of deep levels. DLTS and photocurrent spectra indicate the creation of extended defects in devices aged at very high current density

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This paper presents failure modes observed in long‐term aging of high‐brightness GaN/InGaN LEDs. The blue LEDs submitted to DC aging test present large decrease of emitted optical power and increase of diode reverse leakage current. Increase of parasitic series resistance, suggesting contact degradation, has also been found in stressed sample, together with apparent carrier density increases and reduction of the junction depletion width. Furthermore stressed LEDs present modification of a specific trap property: trap activation energy decreases from 340 meV in the virgin sample down to 75 meV in the stressed sample. Generation of non‐radiative recombination centers seems to be one of the dominant failure mechanisms responsible for the observed electrical and optical LED degradations.

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