本文以硅烷、乙炔和氢气为气源,采用热丝CVD法制备了非晶碳化硅薄膜。通过FITR、紫外-可见光分光光度计、四探针仪、台阶仪和霍尔效应测试仪对薄膜的光学和电学性能进行了系统的研究。结果表明,随着乙炔气体流量的增加,薄膜中碳含量和薄膜光学带隙呈现逐渐递增的趋势,其中光学带隙由1.7 eV上升到2.1 eV。同时还发现B掺杂薄膜的空穴浓度随着B2H6与硅烷流量比的增大而显著增大,而霍尔迁移率的变化趋势则与空穴浓度的变化趋势相反,与二者对应的总体效果是薄膜的电阻率首先显著下降,然后缓慢下降至最小值1.94Ω.cm,此后电阻率略有上升。
Amorphous Si1-xCx(a-Si1-xCx) thin films were deposited from a silane(SiH4),acetylene(C2H2) and hydrogen(H2) gas mixture by hot wire chemical vapor deposition(HWCVD) technique.The photoelectrical properties of the a-Si1-xCx thin films were systematically studied by FTIR,UV-VIS spectra-photometer,four-point probes,surface profile measuring system and Hall-effect measurement equipment.The results indicated that as the C2H2 flow rate increasing,the carbon content and the optical band gap of p-a-Si1-xCx thin films had the tendency to rise,where the band gap increased from 1.7 eV to 2.1 eV.Besides,the hole concentration of the B doped a-Si1-xCx thin films increased significantly as the flow rate ratio of B2H6 to SiH4 increasing,whereas the hall mobility of the film showed a contrary variation tendency.As a comprehensive result,the resistivity of the p-a-Si1-xCx thin films decreased rapidly at first,then gradually reached a minimal value of 1.94 Ω·cm and finally went upward slightly.