The paper focuses on two properties of the multiple oxygen vacancy Eδ' center observed in microelectronic grade oxide films. By monitoring the moisture in the ambient during thermal treatment, we demonstrate the dependence of the Eδ' concentration on H2O. Also, we show that the center concentration does not depend critically on oxide thickness, a result which is consistent with the nonunifonn distribution of defects previously suggested. Samples include oxides buried underneath a layer of Si and nonburied oxides. The centers are generated in the buried oxide regardless of ambient, but in nonburied oxides the density of these centers depends strongly on the moisture level in the ambient gas. Such results should be considered when annealing polysilicon-coated films traditionally employed in switching devices and buried oxides used in high power isolation applications.