Impact of varying electric field: tunneling in deep submicron nMOSFET

The scaling is usually done without corresponding reduction in the supply voltage in the circuit and thus the thin oxide in the MOS structure has shown a large level of electron/hole tunnel injection. The use in the MOS technology of thin oxide films subject to high field has increased the carrier transport within the insulator and these leakage's not only increase the power loss but also are concerned with the reliability of the oxide and in turn with the device. The tunneling current has been found to be dependent on the pulse width of the voltage pulse applied and also depends upon how fast the pulses are being applied. In this work, the variation of the field is assumed to be sinusoidal, i.e. a sinusoidal varying voltage is being superimposed on a static voltage. Since the charge trapping in the gate oxide and at the interface caused by oxide field leads to changes of both the oxide field and shape of tunneling barrier. This results in the variation of the constants of the FN equation. The FN current equation is being modified and found to be dependent on the frequency. It has been found that the ratio of the tunneling current goes on decreasing as the frequency of the varying field is increased