Increased hot-carrier degradation of NMOSFETs under very fast transient stressing

The authors investigate hot-carrier induced degradation of sub-micron NMOSFETs under conditions of drain and gate bias with sub-nanosecond switching times. The results are compared with estimates based on the quasi-static sum of static stresses. Hot-carrier degradation in NMOSFETs subject to sub-nanosecond transient stressing is more severe than estimates based on the quasi-static model suggest. This increased degradation is interpreted as electron traps created by hot holes during the low gate voltage phase followed by electron injecting and trapping during the high gate voltage phase. No detrapping effect was observed during subsequent transient stressing.<>