A PHYSICALLY-BASED MODEL FOR QUANTIZATION EFFECTS IN HOLE INVERSION-LAYERS

As MOS devices have been successfully scaled to smaller feature sizes, thinner gate oxides and higher levels of channel doping have been use d in order to simultaneously satisfy the need for high drive currents and minimal short-channel effects, With the onset and development of d eep submicron (less than or equal to 0.25 mu m gate length) technology , the combination of the extremely thin gate oxides (t(ox) less than o r equal to 10 nm) and high channel doping levels (greater than or equa l to 10(17) cm(-3)) results in transverse electric fields at the Si/Si O2 interface that are sufficiently large, even near threshold, to quan tize the motion of inversion layer carriers near the interface. The ef fects of quantization are well known and begin to impact the electrica l characteristics of the deep submicron devices at room temperature wh en compared to the traditional classical predictions which do not take into account these quantum mechanical (QM) effects, For accurate devi ce simulations, quantization effects must be properly accounted for in today's widely used moment-based device simulators, This paper descri bes a new computationally efficient three-subband model that predicts the effects of quantization on the terminal characteristics in additio n to the spatial distribution of holes within the inversion layer. The predictions of this newly developed model agree very well with both t he predictions of a self-consistent Schrodinger-Poisson solver and exp erimental measurements of QM effects in MOS devices.