Low Temperature Nitridation of Si Oxide Utilizing Activated Nitrogen

Abstract

Oxynitride or nitride films are promising materials as a substitute for silicon dioxide because of their high dielectric constant and blocking effect on B penetration. The purpose of this work is to fabricate ultrathin oxynitride films by nitridation of thermal oxide utilizing activated nitrogen at very low temperature. We analyzed nitrogen concentration in the films using X-ray photoelectron spectroscopy. It was confirmed that 9.6 at.%nitrogen was introduced, and that NSi2O was dominant in nitrided films at temperatures as low as 400°C. We succeeded in decreasing the leakage current by one order of magnitude by nitridation of films with thicknesses of 40–60 nm.