Spectrometry of short-range ions using detectors based on 4H-SiC films grown by chemical vapor deposition

Abstract

Schottky barriers, 10−2 cm2 in area, have been prepared by thermal deposition of Cr in vacuum on 50-μm-thick 4H-SiC epitaxial layers grown by chemical vapor deposition. The uncompensated donor concentration in these films is (4–6) × 1014 cm−3, which makes it possible to extend the depletion region of the detector to ≈30 μm by applying a reverse bias of 400 V. The spectrometric characteristics of the detectors are determined using α particles in the energy range 4.8–7.7 MeV. The energy resolution attained for the 5.0-to 5.5-MeV lines is higher than 20 keV (0.34%), which, by a factor of 2, is second only to precision silicon detectors fabricated by specialized technology. The maximum signal amplitude corresponds, in SiC, to a mean electron-hole pair creation energy of 7.70 eV.