Deposition of heteroepitaxial diamond films on 2 in silicon substrates

Heteroepitaxial diamond films were grown on mirror-polished 2 in (001) silicon substrates by microwave plasma chemical vapour deposition (MWCVD). The surface morphology and crystallographic properties of the films were characterized by scanning electron microscopy (SEM), Raman spectroscopy and X-ray pole-figure analysis. The results clearly show that epitaxial nucleation is achievable over the whole substrate surface, while epitaxial growth can be disturbed by the formation of crystal twins. The growth of misoriented twin crystals depends sensitively on the experimental conditions of the microwave plasma applied during deposition, which are inhomogeneous over the substrate surface. The heteroepitaxially grown films show improved crystallinity and phase purity in comparison with randomly oriented films. Under optimal conditions, it is possible to deposit oriented diamond films on an area of greater than 20 cm(2).