Performance of irradiated bulk SiC detectors

Abstract

Silicon carbide (SiC) is a wide bandgap material with many excellent properties for future use as a detector medium. We present here the performance of irradiated planar detector diodes made from 100-μm-thick semi-insulating SiC from Cree. Ohmic/Schottky diodes were produced and characterised using Schottky barrier measurements and charge collection efficiency (CCE) measurements were made for 5.48MeV241Am alpha particles. Charge collection of ∼60% was measured initially. Measurements were taken of trap lifetimes in an effort to understand this. Three distinct traps with lifetimes of 4, 16, and 130s were found. Irradiation took place at Paul Scherrer Institute (PSI) to fluences of 1012, 1013, and 5×1014cm−2, with 300MeV/c pions. Changes in the Schottky barrier height, leakage current, trap lifetimes, and CCE measurements give an indication of the possible degradation in performance of detectors of this type over their projected lifetime.