Study of Schottky barrier detectors based on a high quality 4H-SiC epitaxial layer with different thickness

Abstract Schottky barrier detectors based on a high-quality 4H-SiC epitaxial layer with varied thickness up to 70 μm were studied. The detectors had front-side circular Ni/Au Schottky contacts and a back-side full-area Ti/Pt/Au ohmic contact. Current-voltage characteristics in the reverse and forward directions of prepared detector structures were measured. The typical reverse current of the detector structure was below 50 pA at room temperature. The Schottky barrier height, series resistance and ideality factor were evaluated from the forward part of the current-voltage characteristics, and they were 1.3 eV, 1.33, and 638 Ω, respectively. Capacitance-voltage measurement of the detectors up to 600 V was also realized. This provided data to calculate the depletion width, concentration profile and barrier height. The lowest doping concentration of about 7 × 1013 cm−3 was determined. The spectrometric performance of the Schottky barrier detector structures was analyzed using an α-particle radioisotope source. The detector structures demonstrated a high energy resolution below 20 keV in the full width at half maximum for 5.5 MeV α-particles.