DISLOCATIONS AND SUBSTRUCTURE IN LARGE 0 DEGREES CZOCHRALSKI SAPPHIRE CRYSTALS

The crystal perfection of O° Czochralski grown sapphire was examined by a PbOPbF2 etchant and quantitative x-ray measurements. The (0001) planes from different sections of a large boule contained a minimum etch pit density of 104/cm2 and a maximum of 105/cm2. The misorientations in (1120) planes by Laue case diffraction were 0.2-3 min. For (00.12) planes by Bragg case diffraction, the maximum mis-orientation is 0.5 min. These data are 10 - 100 times lower than reported results on Verneuil grown material. © 1969.