Speaker
Description
The study is focused on the impact of heavily damaged Bragg peak region (BPR), which arises in Si p+-n-n+ diodes at the end of 15 um track of 53.4 MeV 40Ar ions on the degradation of the bulk current The method of the study included simulation of ion collisions with the silicon atoms, the measurements of I-V and C-V characteristics of irradiated diodes and their treatment using a specially built algorithm. It was revealed that the profiles of the current density gradient dJ/dx (the current generation rate) demonstrated nontrivial shapes with two features: the maxima shift from the BPR, and a plateau with a reduced dJ/dx inside the BPR. These features are related, respectively, to the contribution of the diffusion current of holes outflowing from the nondepleted BPR to the total current, and an exhaustion of hole current from the depleted BPR. The main result important for practice is that suppression of the current is a common effect for Si sensors with regions enriched with defect clusters, such as track ends of short-range ions, or uniformly damaged regions in sensors irradiated with hadrons at fluences beyond 10^16 neq/cm2.
