采用等离子体增强化学气相沉积技术, 以N2掺入到SiH4和H2的沉积方式, 分别在玻璃和N型单晶硅片(100)衬底上制备富硅氮化硅薄膜。 通过紫外-可见光吸收光谱、 傅里叶变换红外吸收光谱(FTIR光谱)、 拉曼光谱和光致发光谱(PL谱)分别表征掺氮硅薄膜材料的带隙、 结构及其发光特性的变化。 结果表明: 在氢气的氛围中, 随着氮气流量的增加, 氢原子能够对薄膜缺陷起到抑制作用, 并使较低的SiH4/N2流量比下呈现富硅态, 但却不利于硅团簇的形成。 随着氮原子的掺入, Si—N键的含量增大, 带隙增大, 薄膜内微结构的无序度也增大, 薄膜出现了硅与氮缺陷相关的缺陷态发光; 随着氮原子进一步增加, 出现了带尾态发光, 进一步讨论了发光与结构之间的关联。 这些结果有助于采用PECVD制备富硅氮化硅对材料发光与结构特性的优化。

High hydrogenated silicon-rich silicon nitride(SiNx∶H)thin films are deposited on the glass and monocrystalline silicon(110) substrates by plasma enhanced chemical vapor deposition using SiH4 and H2 as the main reaction gas with doping the N2. The ultraviolet-visible absorption spectrum, Fourier transform infrared absorption spectroscopy, Raman spectroscopy and photoluminescence spectrum are applied to characterize the changes of the band gap, the microstructure and related photoluminescence properties of the nitrogen-doped silicon film. It shows that hydrogen atoms can suppress the defects in the film and make film present silicon-rich under the low SiH4/H2 flow ratio, but they are not beneficial to the formation of silicon clusters in a hydrogen atmosphere. With the incorporation of nitrogen atoms, all the content of Si-N bonds, band gap and the degree of disorder in the microstructure of the films increase, films produce light emission related to the defect states. While the content of doped nitrogen atoms are further increased, it appears the band tail emission. Then the relationships between several light emissions and microstructure to be discussed. These results are useful for the optimization of light emission and microstructure for the silicon-rich silicon nitride film material prepared by PECVD.