GROWTH AND CHARACTERIZATION OF ANODIC OXIDES ON SI(100) FORMED IN 0.1M HYDROCHLORIC-ACID

Anodic oxides of thickness 1-10 nm have been grown on Si(100) using an odic oxidation at room temperature. The electrolyte was 0.1 M HCl. The effects of the anodic potential, growth time, external visible illumi nation intensity, substrate doping type, and density on the oxide thic kness were determined. Coulometric and etching experiments suggest tha t no silicon is lost to the 0.1 M HCl solution. Under sufficient visib le illumination, the oxide thickness was independent of dopant level f or n-type substrates and only weakly dependent for p-type substrates. These results suggest that this technique can be used for accurate dop ant profiling, when combined with cyclical etch back and four-point pr obe electrical measurements. In the dark, the oxide thickness was subs tantially reduced for n-type substrates. This suggests that this techn ique can be used for lateral delineation of n- and p-type regions on p atterned wafers. The as grown oxides were characterized by x-ray photo electron spectroscopy, ellipsometry, and x-ray reflectometry. The subs trates were characterized by Mott-Schottky analysis which, together wi th electrochemical polarization curves, assisted in a qualitative desc ription of the oxide growth as a function of doping density and type. Flatband potentials obtained from Mott-Schottky analysis were obtained at pH 1.1 and 11.7, and show a pH dependence of approximately 60 mV/p H unit, which in contrast to previously reported data indicates an ide al behavior. (C) 1996 American Institute of Physics.