Formation of β-SiC films by ion beam mixing of SiC multilayers

We deposited SiC multilayers of nearly equiatomic composition by ion sputtering of Si and C targets using 1.2 keV Ar+ ions. Ion mixing of these samples was performed with 250 keV Xe+ ions at temperatures ranging between 700 and 900°C. The behaviour of β-SiC formation on mixing was investigated using three techniques: Fourier transform IR spectroscopy, transmission electron microscopy and X-ray diffraction. In addition, X-ray reflectometry measurements were taken to determine the film density. The films produced by mixing at 700°C are amorphous but subsequent annealing at 950°C results in the formation of crystalline β-SiC. Complete mixing of the multilayers is only obtained at 800°C after ion doses higher than 3 × 1016 cm−2, as indicated by cross-sectional electron microscopy. These results demonstrate that ion mixing at moderate temperatures T ∼ 800°C of SiC multilayers may provide an alternative method for the formation of β-SiC films.