Effects of polysilicon gate doping concentration on plasma charging damagein ultrathin gate oxides

Effects of poly-gate doping concentration on plasma charging damage in ultr athin gate oxides were investigated. While the charge-to-breakdown (Q(bd)) value under gate injection stress polarity (-V-g) is independent of the dop ing concentration, eb, under substrate injection stress polarity (+V-g) sho ws a noticeable improvement with increasing doping concentration. However, our results show that plasma-induced oxide degradation is actually aggravat ed with increasing poly-gate doping concentration. These seemingly inconsis tent observations can be explained by the lowering of plasma charging poten tial in the case of insufficient poly-gate doping. (C) 1999 The Electrochem ical Society. S1099-0062(99)10-079-8. All rights reserved.