Reliability of nitrided Si–SiO2 interfaces formed by a new, low-temperature, remote-plasma process

Abstract

Controlled amounts of nitrogen atoms have been incorporated at Si–SiO2 interfaces by a new, low-temperature (300 °C), remote-plasma process, and corresponding improvements in device reliability are reported. Interfacial nitrogen-atom concentrations, up to 1×1015 cm−2, were obtained by a predeposition, remote plasma-assisted oxidation using mixtures of N2O and O2. Auger electron spectroscopy and secondary ion mass spectrometry studies to analyze N-atom concentrations at Si–SiO2 interfaces are discussed. Also, the results of electrical testing of submicron, n-channel metal–oxide–silicon field-effect transistors fabricated with this new process technology are reported. We found that the incorporation of N atoms at the Si–SiO2 interface increased current drive capability at high gate voltages but did not affect the threshold voltage of devices or the peak channel transconductance, gm. Device reliability, as measured by resistance to peak gm degradation after hot-carrier stressing, was found to increase with increasing N-atom concentrations at the Si–SiO2 interface.