Microstructure and Luminous Property of Periodical Gradient Si-rich SiN_x Thin Films

Periodic gradient Si-rich SiNx(G-SRSN) thin films and single-layer Si-rich SiNx(S-SRSN) thin films were deposited on monocrystalline silicon wafers and quartz substrates by combination of magnetron co-sputtering and rapid photo-thermal annealing. Raman spectroscope, grazing incident X-ray diffraction(GIXRD), transmission electron microscope(TEM), Fourier transform infrared(FTIR) spectroscope and photoluminescence(PL) were used to analyze the structure, bonding configurations and luminescence of the films. Raman, GIXRD and TEM results show that the crystalline fractions of G-SRSN and S-SRSN thin films are 41.7% and 39.2%, respectively. Quantum dots density of G-SRSN thin film is 4.4 times higher than that of S-SRSN thin film. The FTIR spectra demonstrate that both G-SRSN and S-SRSN films are Si-rich SiNx, but Si content of the former is lower than that of the later. PL spectra suggest that the G-SRSN thin films possess a lower radiative recombination defect density than the G-SRSN thin films.