Barrier Lowering Effects for Metal-Silicide Schottky Diodes at High Reverse Bias

SummaryFrom experimental data, it is first demonstrated that the common field-dependent lowering models are not sufficient to account for the softness of reverse l(V) characteristics of metal-Silicide Schottky power diodes at high reverse bias voltages. In an attempt to explain this behaviour, we first consider by means of numerical simulations as well as experimental characterizations, the effects of Schottky barrier height inhomogeneities: it is shown that these effects cannot explain the above effect. A new barrier lowering model is then derived from experimental characterization of diode structures exhibiting different technological features (Silicide type, doping level, drift region thickness). A single barrier lowering law versus electric field can be expressed for the complete range of Schottky diodes investigated. This allows a description of metal-Silicide Schottky power diode behaviour at high reverse bias voltages, covering a wider voltage range than previous models, with a good agreement between calculated and experimental data. Numerical results obtained from Pisces simulations using this new model gives equally excellent agreement between simulated and measured values.