The enhanced surface area of silicon nanotexture is an important metric for solar cell integration as it affects multiple properties including optical reflectance, dopant diffusion, and surface recombination. Silicon nanotexture is typically characterized by its surface-area-to-projected-area ratio or enhanced area factor (EAF). However, traditional approaches for measuring EAF provide limited statistics, making correlation studies difficult. In this article, silicon's dominant ultraviolet reflectance peak, R(E2), which is very sensitive to surface etching, is applied to EAF spatial mapping. A clear decay correlation between R(E2) and EAF is shown for multiple textures created using reactive ion etching and metal catalyzed chemical etching. This correlation is applied to R(280 nm) reflectance mapping to yield accurate, high-resolution full-wafer EAF spatial mapping of silicon nanotextures. R(280 nm) mapping is also shown to be sensitive enough to correlate the impact of nanotexture spatial variation on post-diffusion sheet resistance. Finite-difference time-domain simulations of several nanoscale pyramid textures confirm a decay band for R(E2) versus EAF, consistent with our measurements. We suggest that R(E2) mapping may prove useful for other silicon nanotexture properties and applications where EAF is important.

中文翻译：

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使用紫外线反射率绘制硅纳米纹理表面积图


硅纳米结构表面积的增加是太阳能电池集成的一个重要指标，因为它影响多种特性，包括光学反射率、掺杂剂扩散和表面复合。硅纳米纹理的典型特征是其表面积与投影面积之比或增强面积系数（EAF）。然而，测量 EAF 的传统方法提供的统计数据有限，使得相关性研究变得困难。在本文中，硅的主要紫外反射峰 R(E2) 对表面蚀刻非常敏感，被应用于 EAF 空间映射。对于使用反应离子蚀刻和金属催化化学蚀刻创建的多个纹理，R(E2) 和 EAF 之间显示出明显的衰减相关性。这种相关性应用于 R(280 nm) 反射映射，以产生硅纳米纹理的精确、高分辨率全晶圆 EAF 空间映射。 R（280 nm）映射也被证明足够敏感，可以将纳米纹理空间变化对后扩散薄层电阻的影响关联起来。对几种纳米级金字塔纹理的有限差分时域模拟证实了 R(E2) 与 EAF 的衰减带，与我们的测量结果一致。我们认为 R(E2) 映射可能对 EAF 很重要的其他硅纳米纹理特性和应用有用。