Proton microbeam studies of charge collection efficiency in large area silicon carbide detectors

Large area, p–n junction, silicon carbide (SiC) detectors will be used to construct the new particle identification system of the focal plane detector of the MAGNEX magnetic spectrometer foreseeing the NUMEN experimental campaigns. The present work aims to the characterization of these devices in terms of the charge collection efficiency (CCE) both in the inner areas and along the perimeter. Ion beam induced charge technique with a proton microprobe is used for obtaining a 3D characterization of the CCE of the SiC detectors. The technique allows to draw the CCE profile with accuracy as low as 10μm along the surface area and to explore a possible dependence on the depth of the detectors by exploring a range of proton incident energies from 1.26 to 3.92 MeV. In the inner area a good uniformity in the signal collection is found, whereas an anomalous behavior is observed in two of the four edges. The present results suggest the necessity to improve the wafer cutting techniques together with a recast of the edge structures.