Design, Fabrication, Characterization, and Evaluation of X-ray Detectors Based on n-type 4H-SiC Epitaxial Layer

The Schottky barrier diode (SBD) radiation detectors on n-type 4H-SiC epitaxial layer have been designed, fabricated, and evaluated for low energy x-rays detection. The detectors were found to be highly sensitive to x-ray flux in the 50 eV to few keV range and showed significantly improved response compared to the commercial of-the-shelf (COTS) SiC UV photodiodes. Thermally stimulated current (TSC) measurements performed in wide temperature range (94 - 550 K) revealed low density of deep level centers in the epitaxial layer. The high quality of the epitaxial layer was confirmed by XRD rocking curve measurements and defect delineating chemical etching. The detectors fabricated on 4H-SiC epitaxial layers exhibited low leakage current at 475 K (< 1 nA at 200 V) revealing great possibility of high temperature operation.