X- $\gamma$ Ray Spectroscopy With Semi-Insulating 4H-Silicon Carbide

Radiation detectors on a semi-insulating (SI) 4H silicon carbide (SiC) wafer have been manufactured and characterized with X and γ photons in the range 8-59 keV. The detectors were 400-μm-diameter circular Ni-SiC junctions on an SI 4H-SiC wafer thinned to 70 μm. Dark current densities of 3.5 nA/cm² at +20^°C and 0.3 μA / cm² at +104^°C with an internal electric field of 7 kV/cm have been measured. X- γ ray spectra from ²⁴¹Am have been acquired at room temperature with pulser line width of 756 eV FWHM. The charge collection efficiency (CCE) has been measured under different experimental conditions with a maximum CCE = 75% at room temperature. Polarization effects have been observed, and the dependence of CCE on time and temperature has been measured and analyzed. The charge trapping has been described by the Hecht model with a maximum total mean drift length of 107 μm at room temperature.