The effect of subsurface doping on gate oxide charging damage

The effect of wells and substrate type on gate oxide charging damage during plasma processing, and more specifically plasma immersion ion implantation, is modeled. The simulation combines the equations governing the plasma currents and integrated circuit device models to determine the gate oxide stressing voltage during implantation. Depending on the substrate type and the surface potential (V/sub s/), a depletion region may exist, reducing the gate oxide voltage, and hence the gate oxide damage. In addition, well structures, by the nature of their capacitance, modulate V/sub s/, altering the oxide stressing voltage. For most PIII implant conditions, gate oxides with p-type channel doping will be damaged more than those oxides with n-type channel doping. Experimental results confirm the substrate and well effects on plasma charging damage.