Anodic Dissolution during Electrochemical Carrier‐Concentration Profiling of Silicon

Abstract

The anodic dissolution process of silicon in aqueous ammonium‐bifluoride solution during electrochemical carrier‐concentration profiling has been investigated for samples of various crystal orientation as well as dopant type and concentration. The effective dissolution valence and the surface roughness of the etched crater bottom was measured in dependence on the electrode potential, the dissolution current density, the electrolyte concentration, and, as necessary for the anodic dissolution of n‐type material, the illumination intensity. Regions where well‐controlled electrochemical etching occurs producing smooth and flat etched surfaces were defined for all these parameters. An optimized set of parameters for electrochemical carrier‐concentration profiling leading to an effective dissolution valence of for silicon of both polarities is given.