The effect of image potential on electron transmission and electric current in the direct tunneling regime of ultra-thin MOS structures

摘要

The direct tunneling current through ultra-thin gate dielectrics is modeled by calculating the transmission coefficient of an idealized potential barrier that is modified by the image force. A numerical solution to the Schrodinger equation shows that the barrier lowering induced by image-potential affects the tunneling current largely. An analytical ex- pression for the current is obtained within the Wentel-Kramers-Brillouin approximation. The effects of image force on the direct tunneling current are found to increase with the applied voltage across oxide (V_ox) and to decrease with the oxide thickness (T_ox).