Electronic defect states at ultrathin SiO 2/Si interfaces from photoelectron yield spectroscopy

Abstract

The energy distribution of defect states for ultrathin thermally-grown SiO 2/Si(100) interfaces has been quantified by using the total photoelectron yield spectroscopy which enables us to detect the electronic states as low as 10 10 cm −2 eV −1. We have demonstrated that, for as-grown 2.5–4.5 nm-thick SiO 2/Si(100), there exist electronic defect states with a density of 10 11−10 12 cm −2 eV −1 near midgap. It is also found that oxide thinning in a 0.1% HF solution at room temperature eliminates significantly the electronic states above midgap and subsequent 800°C annealing in dry N 2 for 5 min regenerates partly the defect states. These observations suggest the hydrogen passivation of the defect states during the dilute HF treatment and the thermal dissociation of the hydrogen passivation by 800°C annealing.