Ternary mixtures of water, amine, and complexing agent have been found to etch silicon. The silicon etch rate has been investigated.as a function of variations in both solution and material parameters. A parallel investigation has been concerned with the etching characteristics of silicon samples coated with silicon dioxide films. Applications of this etching system to semiconductor device technology has provided a tool for the chemical shaping of silicon as well as the evaluation of protective surface films on silicon substrates.