Structural and optical properties of SiC-SiO2 nanocomposite thin films

This study deals with the deposition of thin films of a SiC-SiO2 nanocomposite deposited on silicon and quartz substrates. The deposition is carried out by a co-sputtering RF magnetron 13.56 MHz, using two targets a... [ view full abstract ]

This study deals with the deposition of thin films of a SiC-SiO₂ nanocomposite deposited on silicon and quartz substrates. The deposition is carried out by a co-sputtering RF magnetron 13.56 MHz, using two targets a polycristallin 6H-SiC and sprigs of SiO₂. In order to study the influence of the deposition time on the morphology, the structural and optical properties of the thin films produced, two series of samples were prepared, namely a series A with a 30 min deposition time and a series B of one hour duration. The samples were investigated using different characterization techniques such as Scanning Electron Microscope (SEM), X-ray Diffraction (DRX), Fourier Transform Infrared Spectroscopy (FTIR), Secondary Ion Mass Spectrometry (SIMS), X rays fluorescence (XRF) and Raman spectroscopy. The results obtained, reveal an optical gap varies between 1.4 and 2.4 eV depending on the thickness of the film; thus depending on the duration of deposition. The SIMS profile recorded the presence of oxygen (¹⁶O) on the surface, which the signal beneath the silicon signal (²⁸Si) and carbon (¹²C) signals, which confirms that the oxide (SiO₂) is the first material deposited at the interface film - substrate with an a-OSiC structure (Figs. 1a and 1b). The photoluminescence (PL) measurement exhibits two peaks, centred at 390 nm due to the oxide and at 416 nm due probably to the nanocrystals of SiC crystals, note that when the deposition time increases, the intensity of the PL drops drastically, result in agreement with dense and smooth film.