INVESTIGATION OF THE LOW-ANGLE GRAIN-BOUNDARIES IN HIGHLY ORIENTED DIAMOND FILMS VIA TRANSMISSION ELECTRON-MICROSCOPY

Highly oriented diamond thin films grown on silicon via microwave plas ma chemical vapor deposition were examined by transmission electron mi croscopy. In the plan view, defects appearing at the grain boundary we re easily observed. (100) faceted grains that appeared to have coalesc ed were connected at their interfaces by dislocations characteristic o f a low angle grain boundary. From Burgers vector calculations and ele ctron diffraction patterns, the azimuthal rotation between grains was measured to be between 0 and 6 degrees. The defect densities of these films are compared to reports from (100) textured randomly oriented fi lms, and the relative improvement due to the reduction of misorientati on and grain boundary angles is discussed.