Space-charge-limited conduction in Si <i>n</i>+–<i>i</i>–<i>n</i>+ homojunction far-infrared detectors

Abstract

An analytic model is presented to describe the space-charge-limited (SCL) conduction in Si homojunction interfacial work-function internal photoemission far-infrared detectors. The basic detector unit is a thin n+–i–n+ structure, which is operated at low temperatures and characterized by an interfacial work function at the n+–i interface. The unique aspects of this case lead to simple analytic expressions for all variables of interest. The barrier shape and free-carrier concentration distribution in the i layer, and their dependence on the applied bias, i layer thickness, and compensating acceptor concentration, are calculated. The SCL current–voltage characteristic is also investigated as a function of i layer parameters. The results obtained are useful for the IR detector design and performance optimization.