Fabrication and Characterization of Silicon Nanoparticles Embedded in SiNx Films

Nonstoichiometric silicon nitride (SiNx) thin films with silicon nanoparticles were deposited on p-type crystalline silicon and quartz substrates at low temperature (200 degrees C) using ammonia and silane mixtures by plasma enhanced chemical vapour deposition (PECVD). The thin films structure was improved by high-temperature (range 500-950 degrees C) annealing. The photoluminescence (PL) spectroscope, Raman spectra and Fourier transform infrared spectroscope (FTIR) of the SiNx thin films annealed at different temperatures were investigated at room temperature. The structure, luminescence and bonding configurations of the thin films were analyzed. Raman spectra showed that the silicon nanoparticles embedded in SiNx thin films were amorphous structure. Two PL spectra bands related to silicon nanoparticles were observed from PL spectra and their peak shifts were the same with increase of annealing temperature. For samples annealed below 800 degrees C, the PL peaks show a blue-shift with increasing annealing temperature, while for the samples annealed over 800 degrees C, an obvious red-shift of PL peaks is observed. Three kind of spectral analyses of the films show that photoluminescence of the thin films was attributed to quantum confinement effect of silicon nanoparticles. These results have valuable implications for the optimization of silicon nanoparticles fabrication process and silicon nanoparticles photoelectric device applications.