THERMAL-EXPANSION OF CHEMICAL-VAPOR-DEPOSITION GROWN DIAMOND FILMS

The thermal expansivity of chemical vapor deposition (CVD) grown diamond films has been measured from 30 to 700 degrees C by two different techniques. The macroscopic expansivity was determined by standard dilatometric methods, while the microscopic thermal expansivity was measured from the shift of large angle X-ray diffraction peaks. The expansivities, as determined from both techniques, are in agreement, within their experimental errors, but larger than published values for bulk diamond. The difference is assumed to be the result of the presence of non-diamond carbon and defect inclusions in the CVD films.