1 November 2016 Optimization of plasma etching of SiO2 as hard mask for HgCdTe dry etching
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Proceedings Volume 10157, Infrared Technology and Applications, and Robot Sensing and Advanced Control; 101573L (2016) https://doi.org/10.1117/12.2247502
Event: International Symposium on Optoelectronic Technology and Application 2016, 2016, Beijing, China
Abstract
HgCdTe is one of the dominating materials for infrared detection. To pattern this material, our group has proven the feasibility of SiO2 as a hard mask in dry etching process. In recent years, the SiO2 mask patterned by plasma with an auto-stopping layer of ZnS sandwiched between HgCdTe and SiO2 has been developed by our group. In this article, we will report the optimization of SiO2 etching on HgCdTe. The etching of SiO2 is very mature nowadays. Multiple etching recipes with deferent gas mixtures can be used. We utilized a recipe containing Ar and CHF3. With strictly controlled photolithography, the high aspect-ratio profile of SiO2 was firstly achieved on GaAs substrate. However, the same recipe could not work well on MCT because of the low thermal conductivity of HgCdTe and CdTe, resulting in overheated and deteriorated photoresist. By decreasing the temperature, the photoresist maintained its good profile. A starting table temperature around -5°C worked well enough. And a steep profile was achieved as checked by the SEM. Further decreasing of temperature introduced profile with beveled corner. The process window of the temperature is around 10°C. Reproducibility and uniformity were also confirmed for this recipe.
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Yiyu Chen, Yiyu Chen, Zhenhua Ye, Zhenhua Ye, Changhong Sun, Changhong Sun, Shan Zhang, Shan Zhang, Wen Xin, Wen Xin, Xiaoning Hu, Xiaoning Hu, Ruijun Ding, Ruijun Ding, Li He, Li He, } "Optimization of plasma etching of SiO2 as hard mask for HgCdTe dry etching", Proc. SPIE 10157, Infrared Technology and Applications, and Robot Sensing and Advanced Control, 101573L (1 November 2016); doi: 10.1117/12.2247502; https://doi.org/10.1117/12.2247502
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