基于不同单光子能量拉曼谱的氢化硅薄膜微观特性研究

Microstructure research of hydrogenated silicon film based on different excitation wavelength Raman scattering spectra

用等离子体增强化学汽相沉积法(PECVD)在玻璃和单晶硅(c-Si)衬底上分别制备了氢化纳米硅(nc-Si:H)和非晶硅(a-Si:H)薄膜,用紫外、可见和近红外3种不同波长的激光线对不同形态的Si薄膜进行拉曼散射实验研究。研究发现,这些Si薄膜在不同的单光子能量的激光线激发下的拉曼谱线形也不同。进而通过对Si薄膜材料中光吸收系数、折射率、消光系数和穿透深度等的理论分析以及薄膜内部原子数密度及键能密度的计算,对实验结果进行了详细的解释。研究表明,在对Si薄膜微观特性的拉曼光谱研究中,应根据薄膜的具体厚度选择最合适的激发波长,才能对精细微结构获得更为深层次的认识。

In this study,nanocrystalline silicon thin films and amorphous silicon thin films are grown on both the single crystalline silicon and glass substrates by plasma-enhanced chemical vapor deposition （PEVCO）. Raman scattering is used on those films by three different excitation wavelengths, from red to near ultraviolet region. It shows that the Raman spectrum is different by varying the incident wavelength based on analyses of the incident light intensity energy, the photo absorption coefficient of silicon and the penetration depth. The experimental results are well explained by the theoretical analysis of thin film in- ter atomic number and bond energy. It shows that the optimum laser should be chosen in order to get further information of material microstructure. The results are advantageous to characterize the compos- ite microstructures and the interface between those different materials. Different Raman spectra excited by deferent wavelengths are also valuable to explain the material damage and failure with service.