Modeling of cryogenic capacitance–voltage (C–V) profiling for the determination of minority doping concentration in blocked impurity band (BIB) detector structures

A finite difference model is used to simulate the low temperature capacitance–voltage (C–V) profiling technique used for the measurement of minority dopant concentrations in the active layer to blocked impurity band detectors. The numerical modeling provides a complete description of the space charge distribution throughout the entire multilayer device and its response to voltage modulation during C–V profiling. C–V profiles are calculated for a range of doping gradients between the heavily doped active layer and the high purity blocking layer. We observe a range of non-linear behavior in the C–V profile with increasing gradient. This can result in an over-estimation of the minority doping in the active layer when applying standard analytical expressions that do not include distributed space charge effects in the data analysis.