Three-dimensional simulation of VLSI MOSFET´s: The three dimensional simulation program WATMOS

A computer simulation program based on a three dimensional model for MOSFET devices was developed. The simulated device structure is quite general and both physical and geometrical parameters can be varied. This program was used succesfully to study a number of fundamental properties of small geometry devices. The three dimensional simulations revealed a new insight into small geometry devices. Some of these results include, "side-walk" effect due to the field oxide charge; \´saddle-point\´ related to punchthrough current locus, the punchthrough current as a function of device width varies exponentially; "wedge" like effective channel width the potential and the electric field distributions, avalanch breakdown and threshold voltage are significantly different from those calculated using two dimensional analysis.