Dislocation clusters in Czochralski-grown single crystal indium phosphide

Abstract

Clusters of etch pits which sometimes form in single crystal indium phosphide grown by the Czochralski liquid-encapsulation technique, are shown to equate with prismatic dislocation loops generated by a stress source at the centre of the cluster. The morphology of the clusters and the conditions under which such clusters form are shown to be consistent with the presence of either a precipitate or an inclusion. It is demonstrated that water vapour associated with the boric oxide used as the liquid encapsulant is a positive cause of clusters and that vacuum baking is a pre-requisite for their control. The elements responsible for the stress generation promoting the clusters have not been positively identified but the likely possibilities are discussed.