The effects of nitrogen implantation into P/sup +/ poly-silicon gate on gate oxide properties

We have studied the effects of nitrogen implantation into P/sup +/ poly-silicon gate on gate oxide properties in detail for the surface channel PMOS below 0.25 /spl mu/m. It was founded that boron penetration through the gate oxide film can be effectively suppressed by nitrogen implantation into P/sup +/ poly-silicon gate. Moreover the generation of interface states and traps can be also reduced by nitrogen implantation. Therefore the resistance against the hot carrier injection can be dramatically improved. These improvements would be due to the incorporation of nitrogen into gate oxide film and the reduction of boron and fluorine atoms in the gate oxide film. >