Threshold voltage of narrow channel field effect transistors

A new effect associated with Metal-Oxide-Silicon Field-Effect-Transistors (MOS-FET's) is presented in this paper. MOS-FET's show an increase of threshold voltage with decreasing ratio of channel width to gate depletion width. This narrow channel effect is explained by means of geometrical edge effects. With decreasing channel width the transition from the field oxide depletion region to the gate oxide depletion region becomes comparable to the gate width and cannot be neglected in the derivation of the threshold voltage equation.A theoretical model is given to explain the influence of decreasing channel width on the threshold voltage as well as on other electrical parameters. This theoretical model is in good agreement with experimental results given in this paper.