Electron, Neutron, and Proton Irradiation Effects on SiC Radiation Detectors

Owing to their low dark current, high transparency, high thermal conductivity, and potential radiation hardness, there is a special interest in silicon carbide (SiC) devices for radiation monitoring in radiation harsh environments and with elevated temperatures and, especially, for the plasma diagnostic systems in future nuclear fusion reactors. In this work, four-quadrant p-n junction diodes produced on epitaxial 4H-SiC substrates are studied. The impact of electron, neutron, and proton irradiations (up to fluences of $1 \times 10^{16}$ electrons (e)/cm$^{2}$, $2 \times 10^{15}$ neutrons (n)/cm$^{2}$, and $2.5\times 10^{15}$ protons (p)/cm$^{2}$, respectively) on the electrical characteristics is studied by means of current–voltage ( $I$ – $V$ ) and capacitance–voltage ( $C$ – $V$ ) techniques. Regardless of the particle type and applied fluences, the results show similar low reverse currents for irradiated SiC devices, which are at least about four orders of magnitude lower than comparable Si devices. The effects of irradiation on interquadrant resistance and charge build-up in the interquadrant isolation are assessed. Furthermore, device performance as a radiation detector is investigated upon exposure to a collimated $^{239}$ Pu–$^{241}$ Am–$^{244}$ Cm tri-alpha source. The performance at room temperature is preserved even for the highest irradiation fluences, despite the fact that the rectification character in electrical characteristics is lost. From the results, advantages of using SiC devices in alpha particle detection in harsh environments can be envisaged.