The influence of temperature, KF concentration, and relation rate on the photoanodic dissolution of a rotating disk n-type Si electrode in water/ethanol/HF solutions has been studied. The dissolution process was found to be under mixed kinetic and diffusion control. The overall reaction takin,a place at a current peak, characteristic for the anodic dissolution of Si in HF solutions, was split into two reactions: the anodic oxidation of Si to an oxide and the chemical dissolution of this oxide by HF. This dissolution reaction was second order in HF concentration. A Koutecky-Levich-like equation for a second order reaction was derived. The peak current was analyzed according to this equation. A good agreement between calculated and experimental data was obtained. (C) 2000 The Electrochemical Society. All rights reserved.