Several prototype devices have been manufactured and tested showing very promising or even outstanding results compared to other semiconductors.
In this presentation we show the results of our research activity, whose aim was to deeply understand the physical and electronic characteristics of 4H-SiC available for device construction and, at the same time, to develop a technology able to realise high performance radiation detectors.
For this purpose we have designed and manufactured several types of device, test structures and detectors on epitaxial 4H-SiC, 30 to 70 μm thick, furnished by different foundries, with doping concentrations ranging from 5x10¹³ to 10¹⁵ cm^-3. Residual doping in the epitaxial layer should be as low as possible in order to deplete thick layers at adequate voltage, so maximising the detection efficiency at low reverse current and reasonable charge collection times. The detector Schottky contacts with Au and Ni₂Si have been tried, giving barrier heights around 1.2-1.6 eV, ideals to made negligible thermionic emission currents, so achieving low noise. Specifically, on our best devices we have measured dark currents as low as 5 pA/cm² at 27C and 0.5nA/cm² at 100C, which are from two to three orders of magnitude lower with respect to state of the art junctions on silicon or other semiconductors suitable for radiation detectors, such as GaAs, CdTe, CdZnTe. Such ultra-low dark current densities of our SiC detectors allow to reach superior performance in a wide temperature range.
Noise levels as low as 17 electrons r.m.s. at room temperature and 43 electrons r.m.s. has been measured with a pixel detector operating at room temperature and at 100C, respectively, still limited by the noise of the silicon-based front-end electronics.

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1. GaAs and SiC based position sensitive radiation detectors