Characterisation of silicon carbide detectors response to electron and photon irradiation

A preliminary study of the response of SiC devices to 22 MeV electrons and 6 MV photon beams from a linear accelerator is presented in view to assess the feasibility of SiC-based dosimeters. The devices used are 4H-SiC epitaxial n-type layers deposited onto a 4H-SiC n(+)-type substrate wafer doped with nitrogen. Schottky contacts have been formed by gold deposition on the epitaxial layer. The released charge has been observed to increase linearly with the electron dose up to 10 Gy. A linear dependence of the current response of the devices has been also observed as a function of the photon dose-rate in the 2-7 Gy/min range. A preliminary study of the photoconductive response to UV irradiation of semi-insulating 6H-SiC substrates is also reported on samples, with a bulk resistivity of approximate to 10(11) Omega cm, produced with a modified Lely technique.