OXYGEN IN GALLIUM-ARSENIDE

The evolution of the deep level transient spectroscopy spectrum associated with the EL 2 defect in epitaxial as well as bulk GaAs material when they are contaminated by oxygen has been examined in detail. The degree of contamination is evaluated by ion mass spectroscopy. It has been observed that, as previously noticed, the EL 2 spectrum contains two components. From the variations of the amplitude of these components versus time at different temperatures and versus electric field, it is concluded that, while one of these components is associated with the EL 2 defect, the other one originates from the interaction of EL 2 with interstitial oxygen. The deformation of the EL 2 spectrum which is currently observed when using aluminum Schottky barriers is then understood as an effect of oxygen contamination and not due, as previously argued, to changes in the barrier characteristics.