ELECTRON-MICROSCOPY STUDIES OF DISLOCATIONS IN DIAMOND SYNTHESIZED BY A CVD METHOD

High-density dislocations (approximately 5 x 10(8) cm-2) in diamond crystallites synthesized by a chemical vapour deposition method have been studied by electron microscopy. Most of the dislocations, having the Burgers vector of 1/2<110>, are seen undissociated by the weak-beam observation and are often zigzag in shape on a climb-plane. Some dislocations lying on {111} glide planes are dissociated into Shockley partials. The stacking fault energy estimated from the separation of the partials is 290 +/- 40 mJ m-2, which is substantially the same as that reported for natural diamond. In some crystallites, high-density twins are observed instead of dislocations.