MOS structure with a P+P profile

Abstract

A simple semi-analytical method is proposed to compute the principal characteristics of non-uniformly doped MOS devices. By considering an inversion layer with a non-zero width it is possible t o compute the complete C-U curve. The influence of the doping profile on the characteristics of such structures is shown. The high frequency C-U curve calculated by means of the method leads to a more accurate definition of the threshold voltage. Finally, t h e described model may be applied to compute the drain current of non-uniformly doped P+P MOS transistors in good agreement with the experimental values.Le modble semi-analytique simple propose ici est destine au calcul des principales caractbristiques de structures MOS 8, dopage non-uniforme. La prise en compte d'une largeur non nulle de zone d'inversion permet d'6tablir la courbe C-U dans son entikrete.On montrera comment le profil d'impuretbs influence le comportement de tels dispositifs; d'autre part, sur base de courbes C-U haute frbquence 6tablies 8, partir du modble, on pourra prbciser la notion de forte inversion dans ces m6mes structures. Enfin, la mbthode proposbe est appliqnb avec succbs au calcul du courant de transistors MOS B dopage nonuniforme.