NEW DEVELOPMENTS IN THE GROWTH OF EPITAXIAL CUBIC BORON-NITRIDE AND DIAMOND FILMS ON SILICON

We report on the first successful growth of oriented crystalline diamond on the (001) surface of cBN/Si substrates using the method of pulsed laser deposition. X-ray diffraction measurements indicate that the diamond layer is 200 Å thick with a lattice constant of 3.56 Å. In addition, new X-ray diffraction measurements performed on boron nitride films deposited by pulsed excimer laser deposition are presented. The X-ray data, taken with both a molybdenum rotating anode source and synchrotron radiation, indicate that the epitaxial cBN films are ≤200 Å thick. The structures of metastable films (cBN and diamond) are very sensitive to growth conditions: we present evidence that an epitaxial-crystalline to incoherent phase transition occurs when the thickness of the films exceeds a critical value (∼ 200 Å for our present growth conditions). © 1992.