Silicon oxynitride films prepared by plasma nitridation of silicon and their application for tunnel metal-insulator-silicon diodes

Abstract

Silicon oxynitride films in the thickness range 1–6 nm have been prepared by nitridation of silicon in a NH3/H2 plasma at a temperature of 340 °C. An O/N ratio of 1.5 and a significantly smaller amount of excess silicon compared to ultrathin thermal silicon oxide films was found by Auger electron spectroscopy. Silicon oxynitride films of only 1.3 nm in thickness turned out to be good oxidation barriers up to 980 °C and revealed excellent resistance against electron irradiation. Aluminum/silicon oxynitride/p-silicon and aluminum/silicon oxide/p-silicon tunnel metal-insulator-silicon (MIS) diodes were prepared and a nearly identical I-V behavior was observed. However, significantly increased stability of the tunnel MIS diodes with silicon oxynitride was found after life testing at 250 °C. For the two diode structures the different behavior of both series and shunt resistance during the heat treatment is discussed.