Chemical etching and anodic oxidation of (100) silicon in alkaline solution: the role of applied potential

A discrepancy in the results of the potential dependence of the chemical et ch rate of (100) Si in alkaline solutions has been investigated. In contras t to previous work at high temperature, the etch rate of p-type silicon is found to be constant in the range negative with respect to the open-circuit potential while the etch rate of the n-type semiconductor decreases marked ly. In line with some previous suggestions, this difference is accounted fo r by differences in the potential distribution at the semiconductor/solutio n interface, as revealed by electrical impedance measurements under etching conditions. The potential dependence of the anodic current, which is attri buted to electron injection from an intermediate of the chemical etching re action, is also considered.