Effects of interface states on the non-stationary transport properties of Schottky contacts and metal-insulator-semiconductor tunnel diodes

The effects of interface states on the non-stationary transport properties (capacitance and conductance) of Schottky contacts and metal-insulator-semiconductor (MIS) tunnel diodes are studied. Our study is based upon a detailed analysis of the various carrier-exchange mechanisms taking place at a metal-semiconductor contact and incorporates all the effects of the non-equilibrium and non-stationary population of the interface states. The theory offers an unambiguous interpretation of the experimental results in the whole range of biases and frequencies. The relevance of our results for the determination of the density of interface states from capacitance and conductance measurements and for the evaluation of the effects of the interfacial layer thickness in MIS tunnelling diodes has been considered.