The spreading resistance of MOSFET´s

A simple mathematical expression for source and drain spreading resistance near the channel end of MOSFET´s has been derived by calculating the capacitance of the same geometry, using the analogy between the resistivity of conductors and the permittivity of dielectrics (R = ρε/C). Furthermore, it is shown qualitatively and experimentally that the value of the resistivity, which is the most influential parameter in the equation derived, should be determined by a doping concentration equal to the inversion channel carrier concentration, rather than by the source and drain bulk properties.