Reactive ion etching of Germanium using SF6/CHF3/He gas mixture

摘要

The effect of CHF3 gas flow rate on the trench shape and etch rate was studied for germanium-based device fabrication. In this study, a sidewall tilt angle larger than 80° with the trench depth of 300nm was achieved by optimizing the flow rate ratio of SF6/CHF3/He gas mixture. Then, based on the experimental results, a Linear Reactive Ion Etching (RIE) Model was proposed to predict the optimized composition of the SF6/CHF3/He gas mixture to obtain steep trenches with low etch rate, which may provide the guideline for the germanium etching process design.