Plasma damage immunity of thin gate oxide grown on very lightly N/sup +/ implanted silicon

Plasma damage immunity of gate oxide grown on very low dose (2/spl times/10/sup 13//cm/sup 2/) N/sup +/ implanted silicon is found to be improved compared to a regular gate oxide of similar thickness. Both hole trapping and electron trapping are suppressed by the incorporation of nitrogen into the gate oxide. Hole trapping behavior was determined from the relationship between initial electron trapping slope (IETS) and threshold voltage shifts due to current stress. This method is believed to be far more reliable than the typical method of initial gate voltage lowering during current stress.