Degradation and regeneration of recombination parameters can occur in the bulk and at the surfaces of silicon solar cells. This article focuses on the time-resolved analysis of the recombination properties of textured 1.7 Ω cm boron-doped p-type Cz-Si and 5 Ω cm phosphorus-doped n-type Cz-Si wafers, where the surfaces are passivated by n+ poly-Si on interfacial oxide layers exposed to a rapid thermal annealing (RTA) step in a conventional firing furnace. We observe a thermally activated instability in the lifetime over the entire examined injection range. Our experiments show that minority carrier injection (e.g., by illumination) is not required. Degradation in the surface passivation quality of the poly-Si on oxide layer—corresponding to an increase of the saturation current density J0 by up to a factor of five—causes the degradation of the effective lifetime. Interestingly, the surface passivation fully regenerates under prolonged annealing and finally improves even beyond the initial state. Both the extent of the lifetime degradation and the change in J0 depend on the postprocessing treatment temperature which we varied between 80 and 400 °C. Our results indicate that two different processes are responsible for the degradation and the regeneration. Reference samples which did not receive an RTA treatment show no degradation of the surface passivation quality. The RTA treatment applied therefore triggers the degradation effect. A large improvement of the surface passivation quality under prolonged annealing (e.g., at 400 °C) is observed for all samples examined in this study.

中文翻译：

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p型和n型Cz-Si在光照和暗退火下n+掺杂多晶硅表面钝化的降解和再生

复合参数的降解和再生可能发生在硅太阳能电池的本体和表面。本文重点介绍纹理化 1.7 Ω cm 硼掺杂 p 型 Cz-Si 和 5 Ω cm 磷掺杂 n 型 Cz-Si 晶片的复合特性的时间分辨分析，其中表面被 n+ 多晶硅钝化-Si 暴露于传统焙烧炉中的快速热退火 (RTA) 步骤的界面氧化层上。我们在整个检查的注射范围内观察到寿命中的热激活不稳定性。我们的实验表明不需要少数载流子注入（例如，通过照明）。氧化层上多晶硅表面钝化质量的下降——对应于饱和电流密度 J0 的增加高达五倍——导致有效寿命的下降。有趣的是，表面钝化在长时间的退火下完全再生，最终改善甚至超过初始状态。寿命退化的程度和 J0 的变化都取决于我们在 80 到 400 °C 之间变化的后处理温度。我们的结果表明两个不同的过程负责降解和再生。未接受 RTA 处理的参考样品显示表面钝化质量没有下降。因此，应用的 RTA 处理会触发降解效应。