Modeling of steady-state field distributions in blocked impurity band detectors

Abstract

Steady-state electric field and carrier distributions are calculated for blocked impurity band (BIB) detectors in the absence of external illumination. The results illustrate the role of space charge in the blocking layer. Calculations are presented for Ge:Ga, though the input is easily modified for other materials. The numerical model allows for observation of the effect of spatial doping variations and interface gradients. The BIB field distribution is highly dependent on the purity and compensation in the blocking layer, as well as interface sharpness. In some cases, space charge effects can cause a collapse of the field at the blocker/absorber interface or the contact and resultant low field regions in the blocking layer.