On the identity of a crucial defect contributing to leakage current in silicon particle detectors Available to Purchase

The annealing kinetics of the so-called E4/E5 center or E4a/E4b center in electron-irradiated Si particle detectors has been studied at four different temperatures from $23to65°C$ using deep-level transient spectroscopy (DLTS). The center gives rise to two energy levels at 0.37 and $0.45eV$ below the conduction-band edge, and the annealing process is found to be of dissociative nature with an energy barrier of $1.1–1.2eV$⁠. A striking similarity of the annealing rates (and kinetics) is revealed with that obtained for the $936-cm−1$ infrared absorption band, studied by Fourier-transform infrared spectroscopy using identical type of Si material as in the DLTS study but irradiated with neutrons. The result strongly suggest that the E4/E5 levels and the $936-cm−1$ band originate from the same defect, and the latter has been attributed to a di-interstitial-oxygen $(I2O)$ complex. The E4/E5 center plays a crucial role for the detrimental leakage current in irradiated Si particle detectors, and an assignment of E4/E5 to $I2O$ implies that oxygen-lean Si material $(<1014cm−3)$ should be advantageous to enhance detector performance.