Severe silicon lifetime degradation was found after its high-temperature treatment in III-V material growth chambers for the fabrication of III-V/Si multijunction solar cells. Further improvement of the cell efficiency requires insights into the root cause of such lifetime degradation and how to protect the silicon lifetime accordingly. While the exact origins of such degradation remain largely unknown, most published work concluded that extrinsic impurities that diffuse into the silicon bulk during the thermal treatment are the sole reason. In this article, we show that while not necessarily present in every float-zone silicon wafer, grown-in defects that can be thermally activated is also a key mechanism behind the observed silicon lifetime degradation during anneal in our molecular beam epitaxy chamber. As such, annealing of the silicon wafer in the furnace at 1000 °C to annihilate the grown-in defects, together with the deposition of a SiNX diffusion barrier to prevent the extrinsic impurities from diffusing into the silicon bulk, are both required to preserve the silicon lifetime throughout the III-V material growth steps.

中文翻译：

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外延生长室热处理过程中生长缺陷在硅少数载流子寿命退化中的作用


在用于制造 III-V/Si 多结太阳能电池的 III-V 材料生长室中进行高温处理后，发现硅的寿命严重下降。进一步提高电池效率需要深入了解寿命下降的根本原因以及如何相应地保护硅寿命。虽然这种退化的确切根源在很大程度上仍然未知，但大多数已发表的研究得出的结论是，在热处理过程中扩散到硅块中的外在杂质是唯一的原因。在本文中，我们表明，虽然不一定存在于每个浮区硅片中，但可热激活的生长缺陷也是分子束外延室退火期间观察到的硅寿命下降的关键机制。因此，需要在 1000 °C 的炉中对硅片进行退火以消除生长缺陷，同时沉积 SiNX 扩散阻挡层以防止外来杂质扩散到硅块中，以保持硅片的质量。整个 III-V 族材料生长步骤中的硅寿命。