Method for reducing hot-electron-induced degradation of device characteristics

摘要

Hot-electron-induced degradation of a semiconductor device (10) is reduced by converting the silicon surface (18) to a fluorinated-silicon compound interface region (23). The fluorinated-silicon compound interface region (23) is formed by etching the device (10) in a fumer (30) using anhydrous hydrofluoric acid. After a sacrificial oxide is grown over the silicon surface (18), the device (10) is placed in a container (32). A mixture of nitrogen, moistened nitrogen and nitrogen/anhydrous hydrofluoric acid is injected into the container (32) to conduct the etch. The anhydrous hydrofluoric acid converts the silicon to a fluorinated-silicon compound, such as H2SiF6, and water. The fluorinated-silicon compound interface region (23) has stronger molecular bonds than the typical hydrogen-silicon formed at the oxide/silicon interface and is, therefore, less likely to be broken apart by hot-electrons.