Accession Number : ADA265544


Title :   Investigation of Diamond Homoepitaxy by In Situ Fizeau Interferometry: The Role of Oxygen


Descriptive Note : Technical rept. no. 17,


Corporate Author : RICE UNIV HOUSTON TX DEPT OF CHEMISTRY


Personal Author(s) : Rawles, Robin E ; Kittrell, Carter ; D'Evelyn, Mark P


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a265544.pdf


Report Date : 29 May 1993


Pagination or Media Count : 9


Abstract : Optical Fizeau interferometry has been employed as an in situ probe of growth rate and surface morphology in diamond homoepitaxy. The spatial fringe pattern produced by interference between HeNe laser light reflected from the front and back faces of a diamond single crystal is imaged, providing a map of the local substrate thickness. Growth causes the fringe pattern to propagate laterally, enabling in situ monitoring of thickness changes as small as 10 nm. We have investigated the substrate temperature dependence of 100 diamond growth in a hot-filament reactor from 0.5% CH4 in hydrogen with and without oxygen. We obtained an apparent activation energy of 14 kcal/mol over the range 700-1000 deg C for a sample grown from pure methane in hydrogen. The addition of O2 to the reactant feedstock had pronounced effects on the growth kinetics: below 850 deg C the growth rate was enhanced whereas etching was observed above 970 deg C. Treatment of a polycrystalline diamond film under a hot filament with 0.25% O2 in H2 produced etching of both (sup3) and (sup2) carbon


Descriptors :   *DIAMONDS , *EPITAXIAL GROWTH , *OXYGEN , *INTERFEROMETRY , SPATIAL DISTRIBUTION , THICKNESS , MORPHOLOGY , SUBSTRATES , LASERS , HYDROGEN , ACTIVATION ENERGY , NEON , METHANE , HELIUM , CHEMICAL REACTIONS , OPTICAL INTERFEROMETERS , SURFACES , ETCHING , CARBON , VAPOR DEPOSITION , SINGLE CRYSTALS , LIGHT , FILMS


Subject Categories : Physical Chemistry
      Crystallography
      Optics


Distribution Statement : APPROVED FOR PUBLIC RELEASE