MIS TUNNEL ADMITTANCE WITH AN INHOMOGENEOUS DIELECTRIC

A suitable equivalent circuit which incorporates the losses in the oxi de layer of MIS tunnel structures is presented. The frequency dependen ce of the forward capacitance-voltage and conductance-voltage characte ristics also are investigated while taking into account the parallel i mpedance attributed to the insulating layer. In fact, the latter is in cluded in the model as a conductance in parallel with a capacitance, t he contribution of which can be subtracted from the crudely measured d ata. The admittance expression of an ideal MIS tunnel diode can be rea dily derived as a special case from the more general proposed relation s. The effect of the oxide conductance on the overall structure capaci tance is shown to be appreciable at low frequencies. The effect is suc h that the capacitance falls rapidly as the frequency decreases, where as the conductance increases with frequency in the low frequency limit .