Formation of high-quality nitrided silicon dioxide films using electron-cyclotron resonance chemical vapor deposition with nitrous oxide and silane

High-quality silicon dioxide films with nitrogen at the Si/SiO2 interface have been produced by plasma-enhanced chemical vapor deposition using an electron-cyclotron resonance source with silane and nitrous oxide. The nitride layer, which amounts to approximately one monolayer, is produced by a plasma nitridation process that dominates over chemical vapor deposition during the initial stages of growth. X-ray photoelectron spectroscopy has been used to show that the nitrogen atoms are bonded to three silicon atoms and the N-O bond concentration is below the detection limit. Fourier transform infrared spectroscopy indicates that the films have excellent bulk properties. Interface state densities of 2 x 10(11) eV(-1) cm(-2) have been obtained by capacitance-voltage analysis of aluminum capacitors. We discuss the prospects for reducing this level by optimizing the process.