MOLECULAR-BEAM EPITAXIAL GROWN SI1-XCX LAYERS ON SI(001) AS A SUBSTRATE FOR MWCVD OF DIAMOND

Si1-xCx alloy layers are possible candidates for buffer layers in orde r to improve the heteroepitaxy of chemical-vapour-deposited (CVD) diam ond on Si substrates. Si1-xCx layers with carbon concentrations of x < 10% were grown on Si(001) substrates using solid source molecular bea m epitaxy (MBE), CVD diamond films of 20 mu m thickness were deposited on these layers. Raman spectroscopy and X-ray diffraction (XRD) revea l no dependence of the structural properties of the diamond films on t he carbon concentration and morphology of the underlying Si1-xCx layer s. A possible difference in-the degree of orientation of the nuclei is concealed by crystal twinning and defects in the subsequently grown d iamond layer.