CROSS-SECTIONAL SCANNING TUNNELING SPECTROSCOPY OF CLEAVED, SILICON-BASED METAL-OXIDE-SEMICONDUCTOR JUNCTIONS

Cross-sectional scanning tunneling spectroscopy experiments were perfo rmed under air-ambient conditions on cleaved Si-based metal-oxide-semi conductor (MOS) junctions. With the scanning tunneling microscope tip in the vicinity of the oxide-semiconductor interface, the electric hel d-induced depletion region was found to pinch-off the tunneling curren t similar to the effect in a MOS field-effect transistor (MOSFET) wher e increasing gate bias reduces the channel current. In this study, the experimentally observed dependence of the tip-semiconductor I-V chara cteristics on the gate bias was interpreted within a transfer-Hamilton ian tunneling model representing the tip-semiconductor junction and in cluding both tip-induced band-bending and gate bias effects. (C) 1996 American Vacuum Society.