A Unified Quasi-3D Subthreshold Behavior Model for Multiple-Gate mosfets

Based on the quasi-3D potential approach, a unified subthreshold-potential, threshold-voltage, and subthreshold-current model is developed for multiple-gate
mosfet
s including a quadruple-gate, triple-gate, and omega-gate
mosfet
. This work indicates that the scaling-length-oriented subthreshold current roll-up Δ
I
_sub
and threshold voltage roll-off Δ
V
_th
provide the physical insight into well-controlled short-channel effects (SCEs) in terms of effective scaling length
λ
_eff
according to the scaling factor. Besides the decreased minimum conducting channel potential Φ
_C
,min
, the smaller scaling-length-induced effective channel width/height (
W
_eff
/
H
_eff
) reflects the smaller effective conducting cross-sectional area, which reduces the subthreshold current degradation due to the increased subthreshold resistance
R
_sub
. By accounting for the coupling factor in the quasi-3D potential approach,
W
_eff
,
H
_eff
, and Φ
_C
,min
will be increased to some extent to decrease
R
_sub
, which, hence, degrades the subthreshold behavior more extensively in response to SCEs.