Effect of Quantum Mechanical Correction on Drain Current of Ultra Thin Body SOI MOSFET.

Abstract

Impact of Quantum Mechanical correction in surface potential based compact model on the drain current of UTB SOI MOSFET is studied here. Drain current of FD SOI MOSFET is also observed here. As surface potential based compact model we have selected such a model which incorporate the effect of substrate charge explicitly and it also assumed that the silicon film is always fully depleted and the back silicon film surface is never inverted. We have considered a QM correction model (which is basically used in nanoscale MOSFETs) to the surface potential based compact model of Karim and Haque where the effect of wave function penetration into the gate dielectric is taken into account. In our work we have incorporated the effect of this correction on the drain current characteristics of UTB SOI MOSFET. After the inclusion of QM correction in to the front surface potential (sf) of UTB SOI MOSFET increase of sf is observed. Furthermore, QM correction ofsf shows the decrease of drain current of the UTB SOI MOSFET in comparison with the drain current obtain from the semi-classical compact model. For UTB SOI MOSFET, before including QM correction to sf  , a maximum relative error of about 0.6% is obtained between the analytical solution of three surface potentials and iterative solution of exact Poisson equations. In strong inversion, the percentage deviation between saturated drain current of the semi-classical model and quantum corrected model is around 12 – 16%.