The effect of hydrogen on hot carrier radiation immunity of MOS devices

Abstract

The effects of hydrogen on the stability of the SiSiO 2 system are studied using electrical measurements and SIMS analysis of high temperature hydrogen or deuterium annealed MOS devices and capacitors. The effect of hydrogen anneal at 400°C is mainly to reduce the interface state density by passivating the Si dangling bonds. It was found, however, that hydrogen at high temperatures (− 800°C) creates an excess of SiH bonds reaching levels of 10 13 cm −2. While the passivating effect is well known, it is shown here unambiguously that the hydrogen bonds at the interface are precursors for generation of new trapping states under hot carrier or radiation stress conditions. Consequently, MOS devices which were processed with high temperature steps with hydrogen are more susceptible to hot carrier and radiation induced degradation.