An analytical one-dimensional model for lightly doped drain (LDD) MOSFET devices

Abstract

An analytic one-dimensional model for lightly doped drain (LDD) MOSFET devices is presented. This model decomposes the LDD device into an intrinsic MOSFET in series with n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> source and drain diffusion. A conventional charge control model with a pseudo two-dimensional approach was used to calculate the current flow in the intrinsic MOSFET. The voltage drops in the n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> source and drain, including both IR drops and voltage drop across the depletion region of the drain were calculated analytically. By reconstructing all the voltage drops across contact, source/drain, and channel regions, the calculated drain currents as a function of terminal voltages agree well with experimental data. Device optimization is also presented by using this analytical model for "full" LDD and As-P double diffused LDD structures.