Laterally Non-Uniform Doping Profiles in MOSFETs: Modeling and Analysis

As MOSFET dimensions continue to shrink, the promise of further optimizing device performance and the problem of the Reverse Short Channel Effect point to the need for an understanding of the effect of laterally non-uniform profiles on device output characteristics. A semi-analytical model is developed to calculate the current of a device with a laterally nonuniform channel profile, from which a threshold voltage is extracted. The model is tuned to match the results of a two-dimensional numerical simulator. Using this model and the same numerical simulator, the Reverse Short Channel Effect is shown to be caused by a potential barrier at the source. The model is used to explore the relationship between the shape of the lateral doping profile and the shape of the resulting threshold voltage versus channel length curve. By closely fitting data from real devices exhibiting a Reverse Short Channel Effect, the model is able to extract lateral doping profiles for these devices. Thesis Supervisor: Dimitri A. Antoniadis Title: Professor of Electrical Engineering