Response of 4H-SiC Detectors to Ionizing Particles

TLDR

The study reports on the response of newly designed 4H‑SiC Schottky barrier diode detectors to alpha and gamma radiation. The detectors, fabricated with three active area sizes (1 × 1, 2 × 2, and 3 × 3 mm²) and a uniform 4H‑SiC epitaxial layer (~µm thick), were designed to fully stop alpha particles up to 6.8 MeV. The detectors exhibited a linear response to alpha particles from 3.27 to 8.79 MeV and to gamma radiation up to 4.49 Gy/h, with no saturation below 15.3 mGy/min and a measuring range of 0.5 mGy/h–917 mGy/h, while maintaining radiation hardness evidenced by unchanged electrical properties and defect densities.

Abstract

We report the response of newly designed 4H-SiC Schottky barrier diode (SBD) detector prototype to alpha and gamma radiation. We studied detectors of three different active area sizes (1 × 1, 2 × 2 and 3 × 3 mm2), while all detectors had the same 4H-SiC epi-layer thickness of approximately µm, sufficient to stop alpha particles up to 6.8 MeV, which have been used in this study. The detector response to the various alpha emitters in the 3.27 MeV to 8.79 MeV energy range clearly demonstrates the excellent linear response to alpha emissions of the detectors with the increasing active area. The detector response in gamma radiation field of Co-60 and Cs-137 sources showed a linear response to air kerma and to different air kerma rates as well, up to 4.49 Gy/h. The detector response is not in saturation for the dose rates lower than 15.3 mGy/min and that its measuring range for gamma radiation with energies of 662 keV, 1.17 MeV and 1.33 MeV is from 0.5 mGy/h–917 mGy/h. No changes to electrical properties of pristine and tested 4H-SiC SBD detectors, supported by a negligible change in carbon vacancy defect density and no creation of other deep levels, demonstrates the radiation hardness of these 4H-SiC detectors.