The Effect of Novel Deep Donors on the Resolution of Reverse Electrode Germanium Radiation Detectors

A new group of deep donors, designated ETI, has been studied in as-grown n-type ultrapure germanium single crystals [(ND - NA)~1010 cm-3]. The donors have a broad band-type structure consisting of three or more closely spaced peaks (Ec -40 meV to Ec -100meV) as determined by deep level transient spectroscopy (DLTS). Reverse electrode germanium (REGe) radiation detectors which contain ETI are shown to exhibit electron trapping leading to a degradation in resolution as measured by the 1.33 MeV ¿-ray peak of 60Co. The concentration of ETI and the degradation in resolution are strongly correlated.