镶嵌有纳米硅的氮化硅薄膜键合特性分析

采用螺旋波等离子体化学气相沉积(HWPCVD)技术制备了非化学计量比的氢化氮化硅薄膜,对所沉积样品及氮气环境中920℃退火样品的微观结构及键合特性进行了分析.Raman散射结果表明,薄膜中过量硅以非晶纳米粒子形式存在,退火样品呈现纳米晶硅和氮化硅的镶嵌结构.红外吸收和可见光吸收特性比较结果显示,薄膜样品的微观结构依赖于化学计量比以及退火过程,硅含量较低样品因高的键合氢含量而表现出低的纳米硅表面缺陷态密度;退火过程将引起Si-H和N-H键合密度的减少,因晶态纳米颗粒的形成,退火样品表现出更高的结构无序度.

Bonding Structure in Silicon Nitride Thin Films Containing Silicon Nano-Particles

Non-stoichiometric hydrogenated amorphous silicon nitride (a-SiNx : H) film was deposited by helico-wave plasma-enhanced chemical vapour deposition (HWP-CVD) technique. The microstructure and bonding characteristics of both as-deposited and annealed thin films were studied. Raman scattering measurement shows that excess silicon exists in the form of amorphous silicon particles in the as-deposited sample. The microstructure of crystalline nano-particles silicon embedded in silicon nitride matrix in the post-annealed sample was formed. Comparing the results of both the Fourier transform infrared spectra and the optical absorption spectra of the samples deposited under different conditions, it is shown that the microstructure of the thin film depended on the gas flow ratio and annealing process. The sample with lower excess silicon shows a lower density of defect state at the silicon nanocrystal/SiNx interface due to a higher binding hydrogen content. The annealing process induces the decrease in Si-H and N--H binding densities. Because of the formation of silicon nanocrystals, the annealed samples exhibit a higher structure disorder degree.