Cu Contamination Effect in Oxynitride Gate Dielectrics

We have studied the effect of Cu contamination in oxynitride gate dielectrics. Compared to thermal SiO 2 with a physical thickness of 3-5 nm, the oxynitride shows a much improved Cu contamination resistance. Furthermore, the Cu contamination resistance increases with increasing nitrogen content. The mechanism of improved gate dielectric resistance to Cu is due to the strong diffusion barrier properties of oxynitride as observed by secondary ion mass spectroscopy.