Semiconductor multilayer and device fabrication is a complex task in electronics and opto-electronics. Layer dry etching is one of the process steps to achieve a specific lateral device design. In situ and real-time monitoring of etch depth will be necessary if high precision in etch depth is required. Nondestructive optical techniques are the methods of choice. Reflectance anisotropy spectroscopy equipment has been used to monitor the accurate etch depth during reactive ion etching of III/V semiconductor samples in situ and real time. For this purpose, temporal Fabry–Perot oscillations due to the etch-related shrinking thickness of the uppermost layer have been exploited. Earlier, we have already reported an etch-depth resolution of ±16.0 nm. By the use of a quadruple-Vernier-scale measurement and an evaluation protocol, now we even improve the in situ real-time etch-depth resolution by a factor of 20, i.e., nominally down to ±0.8 nm.

中文翻译：

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干涉测量原位 III/V 半导体干蚀刻深度控制，最佳精度为 ±0.8 nm，使用四倍游标尺度测量

半导体多层膜和器件制造是电子和光电子领域的一项复杂任务。层干蚀刻是实现特定横向器件设计的工艺步骤之一。如果需要高精度的蚀刻深度，则需要原位实时监测蚀刻深度。无损光学技术是首选方法。反射各向异性光谱设备已被用于监测原位III/V 半导体样品反应离子蚀刻过程中的准确蚀刻深度和实时。为此，由于最上层与蚀刻相关的收缩厚度而产生的时间法布里-珀罗振荡已被利用。早些时候，我们已经报道了 ±16.0 nm 的蚀刻深度分辨率。通过使用四倍游标尺度测量和评估协议，现在我们甚至将原位实时蚀刻深度分辨率提高了 20 倍，即名义上低至 ±0.8 nm。