High Energy Resolution Detectors Based on 4H-SiC

Abstract

The spectrometric characteristics of the detectors based on 4H-SiC using 4.8-7.7 MeV a-particles were determined. The Cr Schottky barriers with areas of 1×10-2 cm2 were performed^by vacuum thermal evaporation on 4H-SiC epitaxial layers grown by chemical vapor deposition (CVD) with thickness 26 and 50 µm. The concentrations of the uncompensated donors into CVD epitaxial layers were (6-10) ×1014 cm-3, that allowed to develop a detector depletion region up to 30 µm using reverse bias of 400 V. The energy resolution less than 20 keV (0.34%) for lines of 5.0- 5.5 MeV was achieved that is twice as large of the resolution of high-precision Si-based detectors prepared on specialized technology. The maximum signal amplitude of 4H-SiC - detectors corresponding to the average electron-hole pair generation energy was found to be 7.70 eV.

Semi-transparent SiC Schottky diodes for X-ray spectroscopy

“…Silicon carbide (SiC) research has diversified enormously in recent years from its "traditional" base in power switching diodes into a wide range of applications such as trace gas sensing [1], UV detection [2], neutron counting [3], particle tracking [4], alpha particle detectors [5], X-ray analysis [6], and, recently, light ion detection [7]. New detectors based on this wide band gap semiconductor (E g = 3.26 eV) could also find applications in areas such as biosensors [8] and small animal imaging as well as environmental monitoring.…”

High-resolution alpha spectrometry with a thin-window silicon carbide semiconductor detector

“…Although the measured FWHM for 148 Gd is expected to be lower than that for 238 Pu based on the statistics of the number of charge carriers produced, the observed higher value likely results from energy degradation in the 148 Gd source that was used as has been noted previously. [8] Although comparable to or better than previous SiC alphaparticle energy resolution measurements [7,8], the measured FWHMs for SiC are still not as low as can be achieved using silicon spectrometers. The measured alpha-particle pulse height spectrum for a silicon passivated ion-implanted detector supplied by Ortec is shown in Fig.…”

“…The energy required to produce an electron-hole pair has been reported to be (7.7+0.2)eV for SiC. [7,15] Assuming F is also 0.11 for SiC, the calculated statistical broadening is 5.07 keV. A measured value for the Fano factor of <0.04 has been reported for SiC.…”

“…[5][6] Excellent alpha-particle energy resolution has also been reported. [7][8] Ivanov, et al, [7] reported a FWHM of about 20 keV for alpha particles in the 5.4-5.5 MeV energy range for a SiC detector with a 1000-Å chromium Schottky contact. The energy resolution obtained was limited by range straggling effects caused by the Schottky contact [9], which was the entrance window for the detector.…”

“…Although the measured FWHM for 3.183 MeV 148 Gd alpha particles was limited to 41.5 keV by energy broadening caused by the three-layer entrance window, parallel measurements with a silicon spectrometer that had an identical entrance window were used to derive an inherent energy resolution of 19.4 keV for SiC. [8] The inherent SiC energy resolution for SiC was reported by Ivanov, et al to be 18.8 keV [7] based on their measurements. Manuscript A detailed modeling of deceleration of alpha particles in SiC using Monte Carlo methods was carried out by Strokan, et al [9] and Yakimova, et al [10] An 8.75-keV inherent energy resolution was derived for SiC assuming a windowless detector, an electronic noise contribution of 1.7 keV and accounting for statistic fluctuations in the number of charge carriers.…”