Irradiation-induced defects in SiGe

A review is presented on irradiation-induced vacancy-type defects in relaxed Si1−xGex. The emphasis is put on results extracted from deep-level transient spectroscopy (DLTS) investigations of the vacancy, the di-vacancy, the oxygen-vacancy pair (the A-center) and the group-V—vacancy pair (the E-center). The positions of the associated levels in the band gap will in particular be followed as a function of the Ge content and, consequently, of the monotonic decrease of the band gap.