The Fundamental MOSFET Model

Abstract

Metal-oxide-semiconductor field-effect transistor (MOSFET) is the most important device in VLSI (very-large-scale integrated circuit). The fundamental part of MOSFET is MOS diode, and we analyze the surface potential model of the diode, which emerges threshold voltage. We then analyze the drain current model considering carrier velocity saturation at the drain edge. We further analyze channel length modulation, velocity overshoot, and source-drain series resistance. We finally show the scaling theory of the device, which shows a guide line to minimize the device ensuring device operation.

Keywords: Channel length modulation, Depletion approximation, Drain current, Electric field dependent carrier velocity, Electron affinity, Flat band state, Gradual channel approximation, MOS diode, MOSFET, Oxide charge, Poisson equation, Scaling theory, Scattering theory, Source/drain resistance, Subthreshold swing, Vacuum energy level, Velocity overshoot, Work function.