Effect of the electrolyte composition on properties of porous silicon layers

It is shown, on the basis of the IR spectra, that introducing HCl into elec trolyte (water-ethanol solution of HF, intended for the anodic formation of porous silicon) leads to variations in the chemical composition of the sur face of produced layers. It is discovered that the oxygen content in silico n-hydrogen surface compounds decreases, which leads to an increase in hydro phobicity and a decrease in the rate of natural oxidation of silicon by wat er molecules present in the environment. It is assumed that chloride ions t ake part in the electrochemical dissolution of silicon. The assumption is c onfirmed by variations in the polarization dependences and by the decrease in the effective charge spent for transferring silicon atoms from the cryst al lattice into solution.