An improved analytic model for the metal-insulator-semiconductor tunnel junction

Two improvements to a comprehensive analytic model that describes the steady-state current in a metal-insulator-semiconductor tunnel junction are reported. The first modification replaces the conventional two-band representation of the thin oxide band structure with a one-band model. In this approach, the electron barrier height for tunneling is always less than the hole barrier height by an amount equal to the semiconductor bandgap. The second improvement enables the energy dependence of the electron and hole tunneling probability factors to be taken into account. This is accomplished by expressing the tunneling probabilities as short-series expressions. The capability of the model to accurately predict the current-voltage characteristics of MIS tunnel junctions is demonstrated by simulating the DC performance of a tunnel emitter transistor. The results are in good agreement with experimental data