Optimization of etch depth and anisotropy ofIn0.53Ga0.47AsbyCH4/H2reactive ion etching is investigated using a central composite experimental design. Etching characteristics are examined by considering the general trends and main effects of pressure, flow rate, andCH4concentration factors on etch depth and sidewall profile responses. Predictive models are developed using regression analysis for etch depth and sidewall profile responses. These models can be used to predict with 95% confidence etch depth and sidewall profile within approximately 56 nm and 0.16 rad.