An Accurate Model for the Short Channel Insulated Gate Field-Effect Transistor.
STANFORD UNIV CALIF STANFORD ELECTRONICS LABS
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An accurate short channel Insulated gate field-effect transistor IGFET model is described which includes the effect of the drain depletion region on device characteristics in both triode and saturation regions. Calculation of deviations from the classical triode and saturation equations caused by interaction between the drain depletion region and the surface inversion region in devices constructed on lightly doped 10 to the 16th powercu cm substrates is reduced from an analytically untractable two-dimensional field problem to the solution of two simple one-dimensional field problems. In the saturation region, deviation from the classical saturation response is computed from a simple but accurate analytic expression for channel length as modified by the drain depletion region. This bias dependent channel length modifies the forward transfer coefficient of the device such that Beta f V sub G, V sub D. Continuity between triode and saturation characteristics is utilized to define a bias dependent effective threshold voltage V sub TE f V sub G, V sub D, which replaces the classical turn-on voltage in the triode region equation. The overall result is a simple, physically derived model which is shown to accurately describe the terminal characteristics of short channel IGFETs in terms of the geometrical channel length of the device. Author
- Electrical and Electronic Equipment