The effective mass issues in light nitride silicon oxide

Abstract

On the basis of the first-principle calculations, the band-structure properties of light nitride silicon oxide are studied. The average effective electron mass near the bottom of the conduction band is observed to increase exponentially with nitrogen atom concentration. The defect-like energy levels are also observed within the band gap. Due to these levels, the leakage current caused by defect-like states within the band gap may make a larger contribution to the gate leakage current. And thus interpreting the experimental tunnelling current with a single leakage mechanism is not practical. The results also show that a silicon oxynitride dielectric film with a special nitrogen atom concentration can greatly extend the oxide-equivalent thickness.