Experimental and theoretical study of buried channel MOS structures

Abstract

The shape of the potential and space charge density distributions within buried channel MOS structures, obtained from a one‐dimensional numerical solution of Poisson's equation, allows to understand the low‐ and high‐ frequency behaviour and the experimental C–U curves of such structures. The same numerical analysis is also found to be very helpful in the search of a suitable strong surface inversion condition for this type of MOS structures; one may then build up a quite simple theoretical model which leads to the computation of the drain current of buried channel MOS transistors. Experimental devices were made by the SILOX technique. A least squares method is used to determine the actual parameters of the structures. This allows then to compare the results of the theoretical model with the experimental data.