Generation of Si–SiO2 interface states by high electric field stress from low (100 K) to high (450 K) temperatures

Abstract

The temperature dependence (in the range 100–450 K) of the generation of fast interface states at the Si–SiO2 interface by high electric field stress in metal–oxide-semiconductor capacitors when electrons are injected by Fowler–Nordheim tunneling from the Si substrate (n type Si, with a positively biased gate) and from the gate (p type Si, with a negatively biased gate) was analyzed. In both cases, two different temperature regimes can be distinguished, which correspond to two mechanisms responsible for the creation of fast interface states. At stress temperature Ts larger than 180 K, a temperature-activated regime is shown to be consistent with a diffusion of hydrogen-related species, while for Ts<180 K, a nonactivated regime seems consistent with the trapped-hole model. The diffusion coefficients of these hydrogen-related species in the intermediate Ts range 180 K<Ts<300 K were determined. It is DH≊10−14–10−11 cm2/s, in good agreement with the extrapolated values from the known data for the hydrogen diffusion in SiO2 determined at higher temperatures.