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

The thermal expansivity of chemical vapor deposition (CVD) grown diamo nd films has been measured from 30 to 700 degrees C by two different t echniques. The macroscopic expansivity was determined by standard dila tometric methods, while the microscopic thermal expansivity was measur ed from the shift of large angle X-ray diffraction peaks. The expansiv ities, as determined from both techniques, are in agreement, within th eir experimental errors, but larger than published values for bulk dia mond. The difference is assumed to be the result of the presence of no n-diamond carbon and defect inclusions in the CVD films.