A simple model for computer simulation of Schottky-barrier diodes

To simulate the electrical characteristics of metal-semiconductor Schottky barrier diodes, a numerical analysis program based on the Shockley's semiconductor equations has been established. The thermionic emissions of electrons and holes from semiconductor to metal as well as the electric field in the interfacial layer are taken as the derivative boundary conditions of the nonlinear equations. The forward and reverse current-voltage characteristics of various metal-silicon and metal-silicide-silicon Schottky barrier diodes can be simulated by properly choosing the zero-field barrier height and the interfacial-layer capacitance. The barrier height variation as a function of applied voltage is related to the space-charge density and the interfacial-layer capacitance. The nonideality of forward characteristics is attributed to the bending of majority carrier imref and the raising of barrier height. The soft behavior of reverse characteristics can be modeled in terms of the interfacial-layer capacitance.