This paper reports an extensive analysis of the short-term effects of extremely high driving current on the performance and reliability of commercial high-power blue LEDs. To this aim, five different groups of devices, having different structures and chip areas, were submitted to increasing levels of bias current, until catastrophic failure was reached. For the first time we provide information (i) on the reliability limits of LEDs outside the safe-operating area, (ii) on the related failure processes, and (iii) on the impact of current and temperature in determining the degradation of the devices. In addition, the results of failure analysis indicate that for almost all devices, failure occurs in correspondence of a major current injection point, often determined by the presence of crowding phenomena. Failure is ascribed to the high localized power dissipation and temperature. Device layout and intrinsic defects may favour the observed degradation processes.

中文翻译：

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高功率蓝色 GaN LED 在极高温度和电流应力下的效率和灾难性故障

本文报告了对极高驱动电流对商用大功率蓝光 LED 的性能和可靠性的短期影响的广泛分析。为此，具有不同结构和芯片面积的五组不同的器件接受了越来越高的偏置电流，直到发生灾难性故障。我们首次提供以下信息：(i) 安全工作区域外 LED 的可靠性限制，(ii) 相关故障过程，以及 (iii) 电流和温度对确定设备退化的影响. 此外，故障分析结果表明，对于几乎所有设备而言，故障发生在一个主要电流注入点的对应位置，通常是由拥挤现象的存在决定的。故障归因于高局部功耗和温度。器件布局和固有缺陷可能有利于观察到的退化过程。