Homoepitaxial growth and stress analysis of (111) diamond film with embedded gold islands

Abstract

The internal stress in high-quality (111) homoepitaxial diamond film grown on high-pressure high temperature (HPHT) synthesized single crystal diamond substrate by chemical vapor deposition (CVD) can be reduced effectively by embedding Au islands in diamond. Au islands formed from an Au layer deposited on the diamond substrate by electron beam evaporation can be obtained after hydrogen plasma annealing. Transmission electron microscopy and X-ray diffraction results show that the Au islands covered with CVD diamond have a size in a few hundreds of nanometers and are oriented with diamond in the orientation relationship of {111}Au//{111}Dia and <110 > Au//<110 > Dia. The surfaces of the CVD diamond films grown on substrate with and without Au coating exhibit cracks when the film thickness reaches 3.5 μm. As evaluated from the Raman peak shift, it is shown that the internal tensile stress in the film with Au islands is less than in the same thick film on substrate without Au coating. A crack-free (111) homoepitaxial diamond film in the same thickness can be obtained by insertion of multilayers of Au islands in CVD diamond.