Response of 4H-SiC Detectors to Ionizing Particles

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.

Editorial for the Special Issue on “Crystalline Materials for Radiation Detection: A New Perspective”

“…This work consolidates some of the most recent findings and revisits some unsolved issues by analyzing the charge-state dependence of transformation, dissociation, and migration of Si-related intrinsic defects in 4H-SiC. Finally, Bernat et al [5] report the response of newly designed 4H-SiC Schottky barrier diode (SBD) detector prototypes to alpha and gamma radiation. A detector resolution of 3% for the wide alpha energy range, combined with the linear response to gamma, yields rates of up to 4.49 Gy/h, demonstrating the usability of this system for the detection of thermal neutrons and gamma decays.…”

4H-SiC Schottky Barrier Diodes for Efficient Thermal Neutron Detection

“…As already described in our previous work [6], a typical 4H-SiC-based detector has the structure of a SBD. Since neutrons can not be directly detected, their presence is deduced from detection of ionizing neutron reaction products, such as alpha particles and tritons.…”

“…We have recently demonstrated that simple detection devices based on 4H-SiC Schottky barrier diodes (SBDs), equipped with the thermal neutron converter films, have a measurable neutron response, which varies linearly with the incident neutron flux [1,5]. Moreover, the SiC-based detector response to various alpha emitters demonstrates an excellent linear behavior as a function of detector's active area [6].…”

“…The efficient thermal neutron detection can be achieved by using a converter layer rich in isotopes with large cross-section for neutrons with energy in the range of k B T at room temperature (with k B representing the Boltzmann constant). Possible choices are 6 Li, 10 B, 155 Gd, 157 Gd, 235 U, and 239 Pu. For a thermal neutron with kinetic energy E n = 0.0253 eV (which corresponds to a velocity of 2200 m/s), its respective absorption cross-section is σ a = 940, 3800, 61,000, 255,000, 681, and 1017 barn [10][11][12].…”

“…Overall, detectors with either 10 B or 6 LiF are preferred mainly because the energetic charged-particle reaction products are much easier to discriminate from background radiations.…”