Investigations of Oxygen-Defect Interactions between 25 and 700°K in Irradiated Germanium

Abstract

Oxygen impurity atoms interact with radiation-induced defects in germanium over a wide temperature range, producing a variety of optically active oxygen-defect complexes. Two complexes with bands at 719 and 736 ${\mathrm{cm}}^{\ensuremath{-}1}$, not present after irradiation at 25\ifmmode^\circ\else\textdegree\fi{}K, develop on annealing between 58 and 73\ifmmode^\circ\else\textdegree\fi{}K in oxygen-doped Ge. One of these complexes is shown by isotopic substitution to contain oxygen and demonstrates conclusively that impurity-defect interactions occur in germanium at low temperatures. A third band at 620 ${\mathrm{cm}}^{\ensuremath{-}1}$, which develops near 120\ifmmode^\circ\else\textdegree\fi{}K with the disappearance of the first two bands, is also associated with a complex containing oxygen. By analogy to oxygen-defect interactions in silicon, these complexes are postulated to be oxygen-vacancy complexes, formed as the vacancy moves at \ensuremath{\sim}65\ifmmode^\circ\else\textdegree\fi{}K. Many other species develop at temperatures above 273\ifmmode^\circ\else\textdegree\fi{}K. Their annealing behavior indicates that existing complexes react with additional defects or impurity atoms to form new species. Some of the annealing stages occur at temperatures corresponding to annealing stages reported for germanium containing other dopants, suggesting that analogous interactions occur between defects and a variety of impurities.