Ultrathin silicon oxynitride films grown by Ar/N2O remote plasma processing

Abstract

On-line Auger electron spectroscopy, secondary ion mass spectroscopy, and angle-resolved x-ray photoelectron spectroscopy (ARXPS) were employed to determine the concentration, spatial distribution, and local chemical bonding of nitrogen in ultrathin oxynitride films grown by Ar/N2O remote plasma processing. Nitrogen incorporation in the films occurs primarily at the Si–SiO2 interface irrespective of rf power (5–50 W); however, the interfacial nitrogen concentration increases with rf power. Up to 0.6 monolayers of nitrogen atoms, bonded as (Si–)3N, are incorporated at the interface. Atomic oxygen generated in N2O plasma decomposition scavenges nitrogen from the bulk of the film, effectively confining nitrogen to a very narrow region near the substrate. A very small concentration of nitrogen, bonded as (Si–)2N–O, is detected on the top surface of the film by ARXPS.