Reduction of Dislocation Density in Impurity-Doped GaAs Grown on Si Substrate by Molecular Beam Epitaxy

The addition of impurities such as Be and Si during the epitaxial growth of GaAs on Si substrate by molecular beam epitaxy caused the reduction of dislocation density. This was demonstrated by the depth distribution of vacancy-type defects obtained from slow positron measurements and by etch pit observation. The slow positron beam results indicate that impurities, Si and Be, increase concentrations of Ga vacancies and interstitials in the grown GaAs, respectively. The results suggest that these defects assist the enhanced dislocation climb, resulting in the reduction of dislocation density in impurity-doped GaAs.