电子回旋共振等离子体增强沉积氟化非晶碳薄膜的光学性质

用紫外可见光透射光谱(UV-VIS)并结合键结构的X射线光电子能谱(XPS)和红外谱(FTIR)分析,研究了电子回旋共振等离子体增强化学气相沉积法制备的氟化非晶碳薄膜的光吸收和光学带隙性质.在微波功率为140—700W、源气体CHF₃∶C₆H₆比例为1∶1—10∶1条件下沉积的薄膜,光学带隙在1.76—2.85eV之间.薄膜中氟的引入对吸收边和光学带隙产生较大的影响,吸收边随氟含量的提高而增大,光学带隙则主要取决于CF键的含量,是由于强电负 关键词： 氟化非晶碳薄膜 光吸收与光学带隙 电子回旋共振等离子体

OPTICAL PROPERTIES OF AMORPHOUS FLUORINATED CARBON FILMS PREPARED BY ELECTRON CYCLOTRON RESONANCE PLASMA

The optical property of amorphous fluorinated carbon (α-C∶F) films are investigated, which are prepared by microwave electron cyclotron resonance (ECR) plasma chemical vapor deposition (CVD) using trifluromethane (CHF₃) and benzene (C₆H₆) as source gases. The optical energy gap E_g of the α-C∶F films deposited at 140—700W powers and CHF₃∶C₆H₆=1∶1—10∶1 are between 1.76 and 2.85eV. The amount of fluorine in the films has an effect on optical absorption and energy gap. The absorption edge increases as the amount of fluorine is raised. The optical energy gap E_g is mainly determined by CF bond in the films, which results in the change of the density of states in band tail of the valence band.