The nature of prismatic dislocation loops in undoped InP

Abstract

The rectangular prismatic dislocation loops found in single crystals of InP grown from indium-rich melts have been analysed further by transmission electron microscopy (TEM) and a model is proposed for their formation. These loops are shown to be of an interstitial nature and it is proposed that they form by condensation of indium interstitials onto dislocation lines causing climb. Because this climb occurs in the presence of only one native interstitial species, the climbed plane is expected to be imperfect, consisting of either Vp or Inp. Such a defective plane will create a dilation parallel to the plane normal and lead to the displacement fringes observed by TEM. The defective plane is shown to act as a nucleation site for subsequent precipitation at low temperature. EDX analysis suggests that this precipitate is indium.