DEFECTS IN GaAs GROWN ON Ge SUBSTRATES.

The growth of polar semiconducting materials on non-polar semiconducting substrates is illustrated by experimental observations of GaAs grown on Ge substrates and on Ge epilayers which has been grown on Si substrates. The GaAs epilayers are grown in each case by metal-organic, vapor-phase deposition. The GaAs/Ge heterophase junction, the grain boundaries in GaAs grown on left brace 110 right brace Ge and on left brace 001 right brace Ge/Si composite substrates and the anti-phase boundaries in GaAs grown on left brace 001 right brace Ge substrates are each illustrated. The interfaces have been studied by transmission electron microscopy and reveal the pronounced faceting of the anti-phase boundaries in GaAs. Also demonstrated experimentally is the strong interaction between dislocations/grain boundaries and these anti-phase boundaries.