Influences of thermal annealing, the electrolyte pH, and current density on the interface state density distribution of anodic MOS structures

Abstract

/p-Si MOS structures were prepared in 0.1 M K2SO4 electrolyte with a pH of 7 (the 0.1 M KOH solution was buffered with H2SO4) at current densities of 3, 5, and 7 mA/cm2 and with four different pH values of the electrolyte at 3 mA/cm2. It is found that thermal annealing at a relatively low temperature can be used to improve the anodic MOS characteristics. Moreover, of the pH and current density it followed that the pH has a dominant role in the interface electrical properties. The lowest interface state densities at the maximum and the midgap positions are 7.1×1011 and 2.7×1010 eV-1cm-2 for a sample made with pH=7, J=3 mA/cm2. The characteristics of this sample seem satisfactory for device applications of anodized p-Si.