Characterisation of epitaxial diamond films on variously orientated diamond substrates using low-energy electron diffraction, Auger electron emission and Rutherford backscattering

The epitaxial diamond films were grown on (100) and (110) faces by chemical vapour deposition and were of 1,5 μm and 3,0 μm thickness, respectively. Low-energy electron diffraction examination of the as-inserted films revealed the appropriate symmetries. The diffraction patterns obtained for the (100) surface displayed a high spot intensity to background ratio and, in addition, a (2 x 2) surface restructuring. The diffraction patterns obtained for the (110) surface were diffuse with no surface restructuring. Secondary emission examination of the surfaces revealed: (i) An Auger spectrum of energy, line-width and line-shape compatible with that for diamond; (ii) collective bulk and surface plasma oscillations in agreement with that for diamond, including collective oscillation gains above the elastic peak, unique to diamond; (iii) k-shell edge emission reflecting both the electronic band-structure of diamond, in particular the existence of two separate conduction bands, and lowered structure compatible with excitonic effects and Landau damping for diamond. Rutherford backscattering analysis combined with ion channelling was used to confirm that the thinner film was indeed epitaxial and to assess the amount of disorder in both films