A study was made of point defect clusters in high-purity dislocation-free Czochralski and float-zone crystals which were about 50mm in diameter, 11mm thick, and of p-type. High-resolution X-ray diffractometry, absolute integrated intensity measurements and diffuse X-ray scattering were used. The specimens produced sharp diffraction curves, and the integrated intensities were found to be close to the theoretical values for an ideally perfect crystal. An analysis of diffuse X-ray scattering measurements showed that the sources of the scattering were interstitial defect clusters in Czochralski-type material, and vacancy defect clusters in float-zone crystals. By using a phenomenological model, the cluster size, cluster volume and number of defects per cluster were deduced to be 0.8, 2.02 x 10-16cm3 and 1.26 x 106, respectively, for Czochralski material and 0.6,  1.32 x 10-16cm3 and 8.3 x 105 for float-zone specimens.

R.R.Ramanan, G.Bhagavannarayana, K.Lal: Journal of Crystal Growth, 1995, 156[4], 377-82