Nature of traps in gate silicon oxynitride of MOS devices

The goal of present work is to understand the nature of the main traps in gate SiO/sub x/N/sub y/ with the quantum-chemical simulation (MINDO/3). We used the cluster approximation and have studied the electronic structure of the clusters taking onto account the atomic relaxation in different charge states of defects. To simulate the effect of chemical composition on the capturing properties of the /spl equiv/Si/sub 2/N/spl middot/ defect in silicon oxynitride clusters with different numbers of oxygen and nitrogen atoms in the second co-ordination sphere were considered. For simulation of the Si/sub 3/N/sub 4/ bulk electronic structure we used the Si/sub 20/N/sub 28/H/sub 36/ cluster.