Abstract:
Modeling of charge quantization and effects of wave function penetration into gate oxide on
the properties of ultra thin body double gate (OG) MOSFET in deep submicron regime are
studied. Self-eonsistent modeling of double gate MOS inversion layer has been performed,
taking into account the effects of wave function penetration on the solutions of both
Schrodinger and Poisson equations. A solver, based on Finite Element Method, has been
applied for the solution of both Schrodinger and Poisson equations that is much faster and
efficient than conventional Schrodinger-Poisson solver. The developed numerical solver has
been applied to fully depleted OG MOSFET (both n-MOS & p-MOS) for analyzing
electrostatics ofthe device such as, inversion layer charge, average penetration depth, surface
potential and gate capacitance, and hence wave function penetration effects have been
revealed by comparing the results with those of without penetration. Finally, the results have
been compared with established numerical solver. The solver has the capability of analyzing
both symmetric and asymmetric DGMOS structures. Average penetration depth for half of the
silicon film and gate capacitance has been calculated. Wave function penetration effects with
the variation of substrate doping, silicon film thickness and dielectric thickness has been
illustrated. It has been shown that the concept of volume inversion is not accurate for thicker
semiconductor region, Average penetration depth is overestimated and capacitance is
underestimated if the penetration effect is not in consideration. Also it has been shown that
the penetration effect is not same for different oxide thickness, semiconductor thickness and
doping density and the reasons are discussed in details.
