Heteroepitaxial growth of cubic boron nitride on silicon

In this paper 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 Angstrom thick. The authors also report the 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 angstrom thick with a lattice constant of 3.56 Angstrom. The structures of metastable films (cBN and diamond) are very sensitive to growth conditions: the authors present evidence that an epitaxial-crystalline to incoherent phase transition occurs when the thickness of the films exceeds a critical value (∼200 Angstrom for our present growth conditions)