Analytical treatment of MOSFET source—Drain resistance

Series resistance in the metal-oxide-semiconductor field-effect transistor becomes increasingly important as design rules shrink. Material properties associated with the interconnect metal, the semiconductor, and the interface separating the two regions thus assume greater importance. An analytical formulation of the resistance in terms of these material properties is thus quite desirable. We formulate and solve a two-dimensional model of current flow by the method of matched asymptotic expansions. The major utility of this solution is provided by higher order corrections to the standard transmission line model of current flow in the ohmic contact region. We find that present methods for the extraction of material properties from experimental measurements with a transmission line model analysis would be enhanced by the inclusion of higher order terms we present here.