a-Si∶H薄膜的磷-碳二元复合掺杂改性研究

Study on Properties of P-C Doped a-Si:H Thin Films

以SiH4,PH3,CH4为源气体,采用射频等离子增强化学气相沉积(RF-PECVD)方法,通过改变CH4流量制备了磷、碳二元掺杂非晶硅薄膜,研究了磷、碳二元掺杂对薄膜微观结构和光学性能的影响。用X射线光电子能谱仪(XPS)观察到了C-Si峰的存在,同时发现随着CH4流量的增加,薄膜中C元素含量逐渐增大。傅里叶转换红外光谱(FTIR)测试表明,掺杂薄膜中的H含量随着CH4流量的增加逐渐增大,由11.5%增大到24.6%。光学性能测试表明,随着CH4流量的增加,掺杂薄膜的折射率逐渐降低,而光学带隙逐渐增加。

Hydrogenated amorphous silicon （a-Si：H） thin films co-doped with phosphorus （P） and carbon （C） were prepared by radio frequency plasma enhanced chemical vapor deposition （RF-PECVD） using SiH4,PH3 and CH4 as the source gases at various CH4 gas flow rates. The influence of carbon on the microstructure and optical properties of P-doped thin films was studied. The x-ray photoelectron spectroscopy （XPS） spectra show that C-Si bonding can be observed clearly and the C content in the films increases with the increase of CH4 flow rate. The Fourier transform infrared spectroscopy （FTIR） spectra show that the H content grows from 11.5% to 24.6% with the increasing flow rate of CH4. With the incorporation of C,the optical bandgap and the refractive index of the P-C co-doped a-Si：H films vary in the range of 1.96～2.15 eV and 4.22～3.37,respectively.