RELATION FOR THE NONEQUILIBRIUM POPULATION OF THE INTERFACE STATES - EFFECTS ON THE BIAS DEPENDENCE OF THE IDEALITY FACTOR

By an analysis of the exchange of carriers through a semiconductor jun ction, a general relationship for the nonequilibrium population of the interface states in Schottky barrier diodes has been derived. Based o n this relationship, an analytical expression for the ideality factor valid in the whole range of applied bias has been given. This quantity exhibits two different behaviours depending on the value of the appli ed bias with respect to a critical voltage. This voltage, which depend s on the properties of the interfacial layer, constitutes a new parame ter to complete the characterization of these junctions. A simple inte rpretation of the different behaviours of the ideality factor has been given in terms of the nonequilibrium charging properties of interface states, which in turn explains why apparently different approaches ha ve given rise to similar results, Finally, the relevance of our result s has been considered on the determination of the density of interface states from nonideal current-voltage characteristics and in the evalu ation of the effects of the interfacial layer thickness in metal-insul ator-semiconductor tunnelling diodes. (C) 1997 American Institute of P hysics.