The voltage-doping transformation: a new approach to the modeling of MOSFET short-channel effects

It is shown that the influence of the drain-source field on the potential barrier height is physically equivalent to and can be replaced by a reduction in channel doping concentration according to a formula derived from the two-dimensional Poisson equation. The actual barrier height for any drain bias and channel length, on which the derived equation depends, can be calculated easily using well-known one-dimensional (long-channel) solutions. This simple but general procedure, called the voltage-doping transformation (VDT), is shown to lead to analytically calculated potential distributions in fairly good agreement with two-dimensional numerical simulation. An application of the VDT to threshold voltage (V/sub tj/) calculations also is shown. The V/sub th/ model is compared with measurements taken on implanted n-MOSFETs with various channel lengths. Good agreement demonstrates the accuracy of both the VDT and the new V/sub th/ model.<
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