4H-SiC Schottky diodes with Ni2Si contacts for X-ray detection

4H-SiC Schottky photodiodes, with 25?m epitaxial layers, employing thin (20 nm) NiSi Schottky contacts, were investigated for high temperature photon counting X-ray spectroscopy. Important X-ray photodiode detector parameters were extracted from electrical characterization within the temperature range 160 °C to 0 °C. The devices were found to be fully depleted at an applied electric field of 20 kV/cm; a leakage current density of 33 nA cm ± 1 nA cm at 160 °C, was measured for one of the devices. The detectors were subsequently connected to low-noise photon counting readout electronics and investigated for their spectral performance at temperatures up to 100 °C. With the charge-sensitive preamplifier operated at the same temperature as the detector the best energy resolution (Full Width at Half Maximum at 5.9keV) obtained decreased from 2.20keV ± 0.04 keV (120 e rms ± 2 e rms) at 100C to 1.20keV ± 0.03 keV (65 e rms ± 2 e rms) at 0C. The dominant source of noise broadening the Fe X-ray photopeak was found to be the dielectric noise, except for the spectra accumulated at 100 °C and long shaping times (>6?s), in those case the main source of photopeak broadening was the white parallel noise.