Advances in High-Resolution Radiation Detection Using 4H-SiC Epitaxial Layer Devices

Abstract

Advances towards achieving the goal of miniature 4H-SiC based radiation detectors for harsh environment application have been studied extensively and reviewed in this article. The miniaturized devices were developed at the University of South Carolina (UofSC) on 8 × 8 mm 4H-SiC epitaxial layer wafers with an active area of ≈11 mm2. The thicknesses of the actual epitaxial layers were either 20 or 50 µm. The article reviews the investigation of defect levels in 4H-SiC epilayers and radiation detection properties of Schottky barrier devices (SBDs) fabricated in our laboratories at UofSC. Our studies led to the development of miniature SBDs with superior quality radiation detectors with highest reported energy resolution for alpha particles. The primary findings of this article shed light on defect identification in 4H-SiC epilayers and their correlation with the radiation detection properties.

Response of 4H-SiC Detectors to Ionizing Particles

“…The best achieved energy resolution of our detector system, which was calculated from values of the full width at half maximum (FWHM), was 3% for the Am-241 energy of 5486 keV and 3.3% for Gd-148 energy of 3183 keV. The obtained energy resolution is similar to previously published results [11,[17][18][19].…”

“…Keeping in mind that the detection principle lie in the detection of charged particles, the response of the detector to alpha particles is of a particular importance. The best energy-resolution of 0.29% for 5486 keV alpha particles to date, has been reported by Mandal et al [17] with 100% charge collection efficiency (CCE). The energy resolution was found to be dependent on the defect type and concentrations within the 4H-SiC epitaxial layers and on the noise of the detector and associated electronic modules of the detector system [11,[17][18][19].…”

Depth Profile Analysis of Deep Level Defects in 4H-SiC Introduced by Radiation

“…Defect engineering is also used for local carrier lifetime control necessary for the optimization of the switching loss of 4H-SiC power bipolar junction transistors [9] and elimination of the bipolar degradation [10]. In recent years, 4H-SiC radiation detectors have attracted attention due to their high radiation hardness and high signal to noise ratio [11][12][13]. Electrically active defects induced by irradiation negatively affect the performance of 4H-SiC devices during their working lifetime.…”

Study of Annihilation Photon Pair Coincidence Time Resolution Using Prompt Photon Emissions in New Perovskite Bulk Crystals

“…Semiconductor-based detectors have also been studied for prototype positron emission tomography (PET) systems, especially detectors made of cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) [3]- [6]. Semiconductor detectors tend to have better spatial and energy resolution when compared to scintillatorbased radiation detectors [2], [7], [8]. However, when used for PET, they have poor coincidence time resolution (CTR) in the range of several nanoseconds or greater, due to the relatively slow charge carrier collection time limited by the carrier drift velocity.…”