Structural characterization of heavily Zn-doped liquid encapsulated Czochralski InP

A structural characterization of liquid encapsulated Czochralski InP heavily doped with Zn is presented. At a hole density as high as 3.0 x 1018 cm-3, corresponding to a Zn content of 1019 atoms cm-3, the crystals are dislocation-free. They contain, however, a high density (ca. 7 x 109 cm-3) of precipitates identified as Zn3P2 by electron diffraction. This supports the model in which Zn in excess of that occupying In sites as electrically active acceptor can react with the group V element to form precipitates. Other possible lattice locations of the excess Zn cannot be checked by our techniques. The Zn3P2 precipitates tend to disappear for a hole concentration of 2.6 x 1018 cm-3, but dislocations are generated since the hardening effect associated with dopant atoms decreases. The majority of the dislocations have climbed, leaving behind a local high density of microdefects. The possible mechanisms for the generation of these microdefects are discussed.