Asymmetry in the SiO2 tunneling barriers to electrons and holes

Abstract

The potential barriers of ultrathin (%40 Å) SiO2 layers to electrons and holes tunneling between the semiconductor and the metal have been measured independently on the same MOS samples by a new experimental technique introduced in this paper. The method combines dark measurements of current and capacitance versus voltage with measurements of photocurrent suppression under optical illumination. The results show that the tunneling barriers for holes are consistently much larger than those for electrons.