刻蚀工艺对四面体非晶碳膜生长及其性能的影响

Effect of Etching Process on Growth and Properties of Tetrahedral Amorphous Carbon Film

目的研究不同等离子体刻蚀工艺对基体和四面体非晶碳膜(ta-C)的影响,并进一步考察不同电弧等离子体刻蚀时间对ta-C薄膜结构的影响。方法采用自主设计研制的45°单弯曲磁过滤阴极真空电弧镀膜设备,进行不同等离子体刻蚀以及ta-C薄膜的沉积。使用等离子体发射光谱仪表征离子种类及其密度,使用椭偏仪表征薄膜厚度,原子力显微镜表征刻蚀后的基体粗糙度,拉曼光谱仪和XPS表征薄膜结构,TEM分析薄膜的膜基界面结构。结果辉光刻蚀工艺中,作用的等离子体离子以低密度的Ar离子为主;而电弧刻蚀时,作用的等离子体离子为高密度的Ar离子和少量的C离子,并且能够在基体表面形成约15 nm的界面层,并实现非晶碳膜(a-C)的预沉积。随电弧等离子体刻蚀时间增加,ta-C薄膜的sp3含量有所降低。结论相比于辉光刻蚀,电弧刻蚀利于制备较厚的ta-C薄膜。这主要是因为电弧刻蚀时,基体表面形成良好的界面混合层,并预沉积了非晶碳膜,形成a-C/ta-C的梯度结构,有助于增强膜基结合力。

The work aims to study effects of different plasma etching processes on silicon substrate and tetrahedral amorphous carbon（ta-C） films, and further survey effects of different arc plasma etching time on ta-C films. Etching of different plasma and deposition of ta-C films were performed by a home-made 45o bend magnetic filtered cathodic vacuum arc（FCVA） coater.Plasma types and density were characterized with optical emission spectrometer（OES）;thickness of ta-C films with ellipsometer;roughness of treated substrates after etching with atomic force microscope（AFM）;the film structure with Raman spectroscopy and XPS;and film-to-substrate interface structure was analyzed with TEM,representatively.The results showed that the Ar^＋of low density dominated in the effective plasma of glow etching process while Ar^＋of high density and a few C^＋emerged in arc plasma etching process.After the arc plasma etching,a nearly 15 nm thick interface layer was formed on the substrates surface,and pre-deposition of amorphous carbon film（a-C）was observed.Moreover,sp^3 content of the ta-C film decreased as the arc etching time increased.Compared with glow etching process,arc etching facilitates the deposition of thicker ta-C films,primarily due to the formation of interfacial layer on the substrate surface and the pre-deposition of amorphous carbon films layer in arc etching,which contributes to formation of a special a-C/ta-C gradient film structure and improvement of adhesion strength.