Suppression of boron penetration for p(+) stacked poly-Si gates by using inductively coupled N-2 plasma treatment

Abstract

Nitridation of the stacked poly-Si gates by the inductively coupled N-2 plasma (ICNP) treatments has been shown to suppress the boron penetration and improve the gate oxide integrity. The ICNP treatments on the stacked poly-Si layers would create the nitrogen-rich layers not only between the stacked poly-Si layers but also in the gate oxide after post implant anneal, thus resulting in effective retardation of boron diffusion. In addition, the position of ICNP treatment closer to gate oxides leads to higher nitrogen peaks in the gate oxide region, resulting in further suppression of boron penetration and improvement of gate oxide reliability.