低碳含量a-Si_(1-x)C_x∶H薄膜的Raman和荧光特性  

Raman and Photoluminescence Characterization of Hydrogenated Amorphous Silicon Carbide Alloys with Low Carbon Concentrations

作　　者：王燕[1] 岳瑞峰[1] 

机构地区：[1]清华大学微电子学研究所,北京100084

出　　处：《真空科学与技术》2001年第2期120-124,共5页Vacuum Science and Technology

基　　金：国家自然科学基金青年基金资助项目! (5 970 2 0 0 5 )

摘　　要：采用Raman和荧光测量研究了低碳含量a Si1-xCx∶H(x≤ 2 0 % (原子比 ) )薄膜的结构特征 ,并选用两种不同波长的激光来激发这些材料。采用 6 47.1nm光激发时 ,由于激发光能量接近于各样品的光学带隙 ,因而在样品中具有较大的透射深度 ,而 488 0nm光激发时则被样品表面强烈吸收。探测深度的变化造成了Raman谱和荧光谱有较大的差异 ,这些结果一方面表明样品的表面存在一层高浓度的缺陷层 ,同时也证明样品体内存在着带隙的空间起伏 ,这两种空间的不均性造成了高能激发时Raman谱的TO模频率和半高宽比低能激发时有大的红移和展宽 ,而荧光峰和半高宽则有小的蓝移和展宽。以上结果表明在a Si1-xCx∶H样品中 。The network disorder of the a Si 1- x C x ∶H films with carbon concentration lower than 20 at.% has been studied with Raman spectroscopy and photoluminescence spectroscopy (PL).Two different laser irradiation wavelengths were employed to excite the materials,one with a wavelength of 647.1 nm and an energy close to the optical gap of the material,can penetrate fairly deep into the material,whereas the other with a wavelength of 488.0 nm and an energy higher than the optical gap,can be almost completely absorbed by the surface of the materials.The variations in penetration depth result in significant differences between Raman spectra and PL spectra.These results indicate that there exist high density defects in the layers close to the surface,and that the spatial fluctuation of the gap due to variation in bulk concentrations.The complex microstructures of the films are responsible for the marked red shift and broadening of the frequency and width of the TO mode of the Raman spectra and a small blue shift and broadening of the PL peak when the sample was excited with a high laser energy.These observations show that in the a Si 1- x C x ∶H sample,irradiation energies may strongly affect the results of Raman spectroscopy and PL measurements because of the complexity of the microstructures of the films.

关 键 词：碳化硅薄膜 RAMAN谱 荧光测量 结构 荧光光谱 

分 类 号：O484.5[理学—固体物理]