Modeling and characterization of direct tunneling hole current through ultrathin gate oxide in p-metal-oxide-semiconductor field-effect transistors

Abstract

We report the calculation of hole direct tunneling (DT) current from the inversion layer in a p-metal-oxide-semiconductor field-effect transistor based on a solid physical background. Our results are in good agreement with those obtained from carrier separation measurements over a wide range of oxide thicknesses in the ultrathin regime. The effect of valence band mixing on hole quantization in an inversion layer in a Si substrate is properly accounted for by an improved one-band effective mass approximation. A modified Wentzel-Kramers-Brillouin approximation to calculate the hole transmission probability is used by adopting a more accurate dispersion equation in the oxide gap. Our method is general, simple, and computationally efficient. It may even be used to calculate the hole DT current in other gate dielectric materials. © 2001 American Institute of Physics.