Browsing by Author "Lu, Li-Fang"

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A parabolic potential barrier-oriented compact model for the kappa T-B layer's width in nano-MOSFETs
(2008-05-01)
Chen, Ming-Jer
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Lu, Li-Fang
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
On the basis of a parabolic potential profile around the source-channel junction barrier of nanoscale MOSFETs, a new compact model is physically derived, which links the width of thermal energy kappa T-B layer (a critical zone in the context of the backscattering theory) to the geometrical and bias parameters of the devices. The proposed model is supported by experimental data and by a critical analysis of various simulation works presented in the literature. The only fitting parameter remains constant in a wide range of channel length (10-65 nm), gate voltage (0.4-1.2 V), drain voltage (0.2-1.2 V), and temperature (100 K-500 K). The confusing temperature-dependent issues in the open literature are straightforwardly clarified.
On the Mean Free Path for Backscattering in k(B)T Layer of Bulk Nano-MOSFETs
(2008-12-01)
Chen, Ming-Jer
;
Lu, Li-Fang
;
Hsu, Chih-Yu
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We perform Monte Carlo particle simulations on a silicon conductor for the purposes of reexamining the channel backscattering in bulk nano-MOSFETs. The resulting mean free path lambda(0) for backscattering in a long and near-equilibrium conductor is constant, regardless of the potential profile. However, the apparent mean free path lambda(1) in a local quasi-ballistic k(B)T layer depends on the curvature of the potential profile. In a linear potential profile, the lambda(1) extracted in a wide range of the conductor length (15 to 100 nm) and lattice temperature (150 to 300 K) is found to fall below lambda(0). The carrier heating as the origin of reduced mean free path is inferred from the simulated carrier velocity distribution near the injection point. Strikingly, the mean free paths in a parabolic potential profile remain consistent: lambda(1) = lambda(0) This indicates the absence or weakening of the carrier heating in the layer of interest, valid only for the parabolic potential barrier.