A charge sheet model for MOSFETs with an abrupt retrograde channel Part I. Drain current and body charge

Analytical solutions to drain current, depletion and inversion charges for MOSFETs with an ideally abrupt retrograde doping profile in the channel are derived based on the charge sheet model. The validity of the analytical solutions is confirmed by comparing the modeling results with simulation data obtained using numerical calculations; the modeling and simulation results are in excellent agreement. It is shown that the inclusion of an intrinsic surface layer in the channel causes a voltage shift in the drain current, in accordance with experimental observations. For the depletion charge, an analytical expression principally identical to that for the uniformly doped body case is found with a simple replacement of the surface potential, ψ_s, by the potential at the interface between the intrinsic surface layer and the doped substrate, ψ_ξ.