Inelastic electron tunneling spectroscopy: Capabilities and limitations in metal–oxide–semiconductor devices

We report on inelastic electron tunneling spectroscopy of a tunneling metal–oxide–semiconductor (MOS) device over an extended energy range compared to previous results. We have clearly observed the vibrations of the hydrogen-passivated (111)Si Pb center in this extended energy range. The assignment of this mode has been confirmed by a comparison with infrared experiments. Capabilities and limitations of the technique to detect and observe molecular vibrations in tunneling MOS devices are discussed.