Oxide field and thickness dependence of trap generation in 9–30 nm dry and dry/wet/dry oxides

Abstract

The oxide electric field and thickness dependencies of the oxide electron trap generation rate measured on 86–315 Å thick 900 °C dry oxide and 850 °C dry/wet/dry oxide stressed by substrate electron injection at average dc oxide fields of 1–9 MV/cm are reported. A minimum in the steady-state gate voltage shift versus oxide electric field is discovered which suggests a balance of the field-dependent electron trap charging and discharging rates with the generation rate of oxide traps by oxide field-accelerated hot electrons. The thickness and field dependencies of trap charging, discharging, and generation are compared for two industrial oxidation processes, 900 °C dry and 850 °C dry/wet/dry oxides, and are shown to have similar trap generation rates. A new two-trap generation-charging-discharging model is proposed and shown to give excellent agreement with the experimental data.