Charge collection efficiency mapping of interdigitated 4H-SiC detectors

The Ion Beam Induced Charge Collection (IBIC) technique was used to map the charge collection efficiency (CCE) of a 4H-SiC photodetector with coplanar interdigitated Schottky barrier electrodes and a common ohmic contact on the back side. IBIC maps were obtained using focused proton beams with energies of 0.9 MeV and 1.5 MeV, at different bias voltages and different sensitive electrode configurations (charge collection at the top Schottky or at the back Ohmic contact). These different experimental conditions have been modeled using a two dimensional finite element code to solve the adjoint carrier continuity equations and the results obtained have been compared with experimental results. The excellent consistency between the simulated and experimental CCE maps allows an exhaustive interpretation of the charge collection mechanisms occurring in pixellated or strip detectors.