α-C∶F薄膜的键合结构与电子极化研究

Study on bonding configuration and electronic polarization of amorphous fluorinated carbon films

利用微波电子回旋共振等离子体化学气相沉积技术 ,通过改变微波输入功率的方法 ,沉积了具有不同结构特征的氟化非晶碳 (α C∶F)薄膜。随着微波功率从 14 0W升高到 5 6 0W ,薄膜的光频介电常数从 2 .2 6降至 1.6 8,红外光谱 (FTIR)分析表明薄膜的键结构由以CF基团为主变化到CF与CF2 基团共存。由于CF2 基团的极化比CF基团弱 ,薄膜中CF2

Amorphous fluorinated carbon (α-C:F) films with different structural feature were prepared by microwave electron cyclotron resonance plasma chemical vapor deposition at different microwave input power. The change of film bonding configuration from CF group mainly to coexisting of CF and CF2 groups was found by FTIR and XPS analysis as microwave input power is increased from 140 W to 560 W. The dielectric constant due to electron polarization contribution is decreased from 2.26 to 1.68. The polarization of CF2 group is weaker than that of CF group, so that the decrease of dielectric constant is due to the weaker polarization of CF2 group in the films.