InxGa1-xSb n-channel MOSFET: effect of interface states on CV characteristics

The capacitance-voltage (CV) characteristics of InGaSb based n-MOSFET are investigated by quantum mechanical calculation solving 1D self-consistent Schrodinger-Poisson equation using Silvaco's ATLAS device simulation package. The charge density profile is determined with and without wave function penetration within the oxide layer and Neuman boundary condition. Quasi-static CV characteristics are studied both for the positive and negative interface charge densities. The results obtained from the simulation demonstrate that the significant shift in threshold voltage entirely depends on the polarity of the interface charge density. The oxide-dependent gate capacitance is also explained by simulating first eigen energy with and without wave function penetration.