A simple new method based on the measurement of charge pumping technique is proposed to separate and quantify experimentally the effects of oxide-trapped charges and interface-trapped charges on threshold voltage degradation in p-channel metal-oxide-semiconductor field-effect transistors (pMOSFETs) under hot-carrier stress.Further,the experimental results verify the validness of this method.It is shown that,all three mechanisms of electron trapping effect,hole trapping effect and interface trap generation play important roles in p-channel MOSFETs degradation.It is noted that interface-trapped charge is still the dominant mechanism for hot-carrier-induced degradation in p-channel MOSFETs,while a significant contribution of oxide-trapped charge to threshold voltage is demonstrated and quantified.
The effect of neutral trap on tunneling currentin ultrathin MOSFETs is investigated by num erical analy- sis.The barrier variation arisen by neutral trap in oxide layer is described as a rectangular potential well in the con- duction band of Si O2 .The different barrier variation of an ultrathin metal- oxide- sem iconductor(MOS) structure with oxide thickness of4nm is numerically calculated.It is shown that the effect of neutral trap on tunneling cur- rent can not be neglected.The tunneling current is increased when the neutral trap exists in the oxide layer.This simple m odel can be used to understand the occurring mechanism of stress induced leakage current.
