The formation of vacancy-O complexes (A centers), due to the irradiation of Czochralski-type material with a Ge content of 1018 to 1020/cm3, was studied by means of deep-level transient spectroscopic and Hall effect measurements. It was found that the A centers were not formed at the start of irradiation, and developed only afterwards. In this case, the formation of A centers was thought to be due to the annealing out of certain radiation-induced defects.

K.Schmalz, V.V.Emtsev: Applied Physics Letters, 1994, 65[12], 1575-7