OBSERVATION OF GA VACANCIES IN SILICON DELTA-DOPING SUPERLATTICES IN (001) GAAS

Positron annihilation experiments have been performed to investigate t he compensating defects in silicon delta-doping superlattices in (001) GaAs. The results reveal Vacancies and ion-type defects, which are lo cated between the delta planes in undoped GaAs. The vacancy defect is identified as the Ga vacancy and the negative ion is attributed to the Ga antisite. The concentrations of these defects increase strongly, w hen the areal concentrations of free carriers are reduced at the delta planes. (C) 1997 American Institute of Physics.