Structural and electrical characterization of annealed Si_1-xC_x/SiC thin film prepared by magnetron sputtering

Si-rich Si_1-xC_x/SiC multilayer thin films are prepared using magnetron sputtering, subsequently followed by thermal annealing in the range of 800-1200 ℃. The influences of annealing temperature (T_a) on the formation of Si and/or SiC nanocrystals (NCs) and on the electrical characteristics of the multilayer film are investigated by using a variety of analytical techniques, including X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectrometry (FT-IR), current-voltage (I-V) technique, and capacitance-voltage (C-V) technique. XRD and Raman analyses indicate that Si NCs begin to form in samples for T_a ≥ 800 ℃. At annealing temperatures of 1000 ℃ or higher, the formation of Si NCs is accompanied by the formation of SiC NCs. With the increase in the annealing temperature, the shift of FT-IR Si-C bond absorption spectra toward a higher wave number along with the change of band shape can be explained by a Si-C transitional phase between the loss of substitutional carbon and the formation of SiC precipitates and a precursor for the growth of SiC crystalline. The C-V and I-V results indicate that the interface quality of Si_1-xC_x/SiC multilayer film is improved significantly and the leakage current is reduced rapidly for T_a ≥ 1000 ℃, which can be ascribed to the formation of Si and SiC NCs.