Direct tunneling currents through gate dielectrics in deep submicron MOSFETs

Abstract

A direct tunneling model through gate dielectrics in CMOS devices in the frame of WKB approximation is reported. In the model, an improved one-band effective mass approximation is used for the hole quantization, where valence band mixing is taken into account. By comparing to the experiments, the model is demonstrated to be applicable to both electron and hole tunneling currents in CMOS devices. The effect of the dispersion in oxide energy gap on the tunneling current is also studied. This model can be further extended to study the direct tunneling current in future high-k materials.