A temperature accelerated life test on Upright Metamorphic Ga_0.37In_0.63P/Ga_0.83In_0.17As/Ge triple‐junction solar cells has been carried out. The acceleration has been accomplished by subjecting the solar cells to temperatures (125, 145 and 165°C) significantly higher than the nominal working temperature inside a concentrator (90°C), while the nominal photo‐current (500×) has been emulated by injecting current in darkness. The failure distributions have been fitted to an Arrhenius–Weibull model resulting in an activation energy of 1.39 eV. Accordingly, a 72 years warranty time for those solar cells for a place like Tucson (AZ, USA), was determined. After the ALT, an intense characterization campaign has been carried out in order to determine the failure origin. We have detected that temperature soak alone is enough to degrade the cell performance by increasing the leakage currents, the series resistance, and the recombination currents. When solar cells were also forward biased an increase of series resistance together with a reduction of short circuit current is detected. The failure analysis shows that: a) several metallization sub‐products concentrate in several regions of front metal grid where they poison the silver, resulting in a two times reduction of the metal sheet resistance; b) the metal/cap layer interface is greatly degraded and there is also a deterioration of the cap layer crystalline quality producing a huge increase of the specific front contact resistance, c) the decrease of short circuit current is mainly due to the GaInP top subcell degradation.

中文翻译：

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直立变质Ga0.37In0.63P / Ga0.83In0.17As / Ge三结太阳能电池的温度加速寿命测试和失效分析

直立变质Ga _0.37 In _0.63 P / Ga _0.83 In _0.17的温度加速寿命测试已经进行了As / Ge三结太阳能电池。通过使太阳能电池经受的温度（125、145和165°C）显着高于聚光器内部的标称工作温度（90°C）来实现加速，同时模拟了标称光电流（500倍）通过在黑暗中注入电流。失效分布已拟合到Arrhenius-Weibull模型，其激活能量为1.39 eV。因此，对于像图森（美国亚利桑那州）这样的地方，已经确定了这些太阳能电池的72年保修时间。ALT之后，为了确定故障原因，进行了深入的表征活动。我们已经检测到，仅通过温度浸泡就足以通过增加泄漏电流，串联电阻来降低电池性能，和重组电流。当太阳能电池也被正向偏置时，会检测到串联电阻的增加以及短路电流的减少。失效分析表明：a）几种金属化副产品集中在前部金属格栅的多个区域中，这些区域毒化了银，导致金属薄层电阻降低了两倍。b）金属/盖层界面大大退化，并且盖层的结晶质量也有所下降，从而导致正面比电阻大大增加，c）短路电流的减小主要归因于GaInP顶部子电池降解。a）几种金属化副产品集中在前金属格栅的多个区域中，这些区域会毒化银，导致金属薄层电阻降低两倍；b）金属/盖层界面大大退化，并且盖层的结晶质量也有所下降，从而导致正面比电阻大大增加，c）短路电流的减小主要归因于GaInP顶部子电池降解。a）几种金属化副产品集中在前金属格栅的多个区域中，这些区域会毒化银，导致金属薄层电阻降低两倍；b）金属/盖层界面大大退化，并且盖层的结晶质量也有所下降，从而导致正面比电阻大大增加，c）短路电流的减小主要归因于GaInP顶部子电池降解。