Analytic Oxide Capacitance Model of Double- and Surrounding-Gate Metal-Oxide-Semiconductor Field-Effect Transistors in Linear Region by Considering Inversion-Layer Capacitance

Inversion charge (Q(i)) and oxide capacitance (C'(ox)) of undoped (or lightly doped) or doped double-gate (DG) and surrounding-gate (SG) metaloxide- semiconductor field-effect transistors (MOSFETs) with long channel were analytically modeled by considering inversion-layer capacitance (C(i)) in linear region. The Q(i) model of DG and SG MOSFETs was derived with a closed-form as a function of gate bias (V(GS)), threshold voltage (V(th)), and body structure factor (n) using one-dimensional (1D) Poisson's equation considering the mobile carrier. The n which reflects silicon body structure effect is 1 for DG MOSFETs and less than 1 for SG MOSFETs irrespective of channel doping (N(b)). From the derived Q(i) model considering the C(i) effect, the C'(ox) was modeled and applied to the I(D)-V(GS) model of undoped or doped DG and SG MOSFETs in linear region. The compact current model using our proposed C'(ox) predicted more accurately the on-current behavior than that with the oxide capacitance (C(ox)) in linear region. (C) 2010 The Japan Society of Applied Physics