New developments in the growth of epitaxial cubic boron nitride and diamond films on silicon

Abstract

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 200A˚thick with a lattice constant of 3.56A˚. 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 A˚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 A˚for our present growth conditions).