Modelling of semi-conductor diodes made of high defect concentration, irradiated, high resistivity and semi-insulating material: the current–voltage characteristics

Diodes containing a high concentration of generation–recombination centres can behave in a way, which is not predicted by standard diode theory. Full one-dimensional modelling is reported of the current through a long PIN semi-conductor diode with different concentrations of shallow donors and acceptors, deep donors and acceptors, and generation–recombination centres. From these results we present a physical understanding of the processes involved. The effect on the observed properties for short diodes is also described. An approximate analytical approach is given for a diode with a high defect concentration to complement the standard equations for a diode with a low defect concentration. The results should aid the understanding of the properties of experimental diodes, give an indication of the types of traps in the material and also suggest how their properties may be modified by additional doping. There are specific applications of these results to radiation damaged devices, lifetime killed diodes and devices made from high resistance and semi-insulating materials.