Iodine-Ethanol Surface Passivation for Measurement of Millisecond Carrier Lifetimes in Silicon Wafers with Different Crystallographic Orientations
Iodine-Ethanol Surface Passivation for Measurement of Millisecond Carrier Lifetimes in Silicon Wafers with Different Crystallographic Orientations
复制标题
碘-乙醇表面钝化测量不同晶体取向硅片的毫秒载流子寿命
DOI：
10.1002/pssa.201900257
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Al-Amin M
中科院分区：
文献类型：
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作者：
Al-Amin M
为了改进硅器件的制造工艺，有必要准确地监测大量少数载流子的寿命，这就需要很好地控制表面重组，理想情况下，最小化。良好的表面钝化可以通过热氧化或电介质沉积（例如，Al2O3， SiNx和无定形Si）来实现，但这些钝化形式会改变所研究材料的寿命。各种方案可以在不改变体积的情况下暂时钝化表面，在本文中，探讨了碘-乙醇（I-E）临时表面钝化方案的优点。开发了一种在钝化前制备晶圆片表面的方法。为了优化预处理工艺，对同一铸锭上不同厚度的3-5 Ω cm浮区晶圆进行了一系列实验。这使得材料的整体寿命可以在1015cm - 3注入下测量为46 ms，表面复合速度为6.5±0.3 cm s - 1。然后将I-E钝化与最近开发的超强酸衍生的暂时钝化方案进行比较。尽管后者在（100）取向基板上表现优异，但I-E在（111）取向基板上的表现要好得多，使其成为（111）取向晶圆的更好选择，例如用于功率器件的晶圆。
To improve silicon device fabrication processes, it is necessary to monitor bulk minority carrier lifetimes accurately, and this requires surface recombination to be well controlled and, ideally, minimized. Good surface passivation can result from thermal oxidation or by deposition of dielectrics (e.g., Al2O3, SiNx, and amorphous Si), but these forms of passivation can modify the lifetime of the material under investigation. Various schemes can passivate surfaces on a temporary basis without modifying the bulk, and, in this article, the virtues of the iodine–ethanol (I–E) temporary surface passivation scheme are explored. A procedure for preparing the wafer surfaces prior to passivation is developed. For the optimized pretreatment, a series of experiments on 3–5 Ω cm float‐zone wafers cut from the same ingot with different thicknesses is conducted. This enables the material's bulk lifetime to be measured at 1015cm−3injection as 46 ms, with the surface recombination velocity being 6.5 ± 0.3 cm s−1. I–E passivation is then compared to a recently developed superacid‐derived temporary passivation scheme. Although the latter is superior on (100)‐orientation substrates, I–E performs much better on (111)‐orientation substrates, making it a better choice for (111)‐orientation wafers, such as those used for power devices.