X- Ray Spectroscopy With Semi-Insulating 4H-Silicon Carbide

摘要

Radiation detectors on a semi-insulating (SI) 4H silicon carbide (SiC) wafer have been manufactured and characterized with X and $gamma$ photons in the range 8–59 keV. The detectors were 400-$mu$ m-diameter circular Ni-SiC junctions on an SI 4H-SiC wafer thinned to 70$~mu$m. Dark current densities of 3.5 nA/cm$^{2}$ at $+20^{circ}{rm C}$ and 0.3$~mu {hbox{A}} / {hbox{cm}}^{2}$ at $+104^{circ}{rm C}$ with an internal electric field of 7 kV/cm have been measured. X- $gamma$ ray spectra from ${}^{241} $Am 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 ${rm CCE}= 75%$ 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 $~mu$m at room temperature.