Overlapping electron traps in n-type silicon studied by capacitance transient spectroscopy

In n-type Czochralski-grown silicon samples, a broad unidentified level is observed ∼0.32 eV below the conduction band after high-energy electron irradiation. This level has been investigated in detail using deep-level transient spectroscopy and capacitance-versus-time measurements. The broad level consists of two overlapping but independent peaks which are clearly resolved. The generation rate of these peaks, as a function of bombardment dose and as a function of sample depth, as well as their annealing kinetics has been investigated. The identities of the overlapping peaks are discussed, and our findings are compared with optical and electron paramagnetic resonance (EPR) measurements performed by other authors. In particular, the importance of performing depth profiling when identifying unknown peaks is emphasized. One level is tentatively assigned to a gold-related complex, while the other shows several similarities with the EPR G15 center.