流量比对等离子体基团分布和薄膜结构的影响

Effect of CHF_3/C_6H_6 ratio on distribution of radicals in ECR plasma and bonding configuration of a-C:F film

使用光强标定的发射光谱(AOES)测量了CHF3/C6H6混合气体的微波电子回旋共振(ECR)放电等离子体中基团的分布状态。实验发现随着CHF3流量的增加,成膜基团CF、CF2、CH等的相对密度增大,而刻蚀基团F的密度也会增加,从而使得a-C:F薄膜的沉积速率降低。同时红外吸收谱(IR)分析表明,在高CHF3流量下沉积的a-C:F薄膜中含有更高的C-F键成分。可见在a-C:F薄膜的制备中CHF3/(CHF3+C6H6)流量比是重要的控制参量。

The distribution of radicals in CHF3/C6H6 electron cyclotron resonance (ECR) plasma was investigated by an actinometric optical emission spectroscopy (AOES). The results show that the relative concentration of CF,CF2,C2 radicals increase with the increase of CHF3 flow, while the deposition rate of a-C:F film presents a decreasing trend. The results also suggest that the relative content of C-F bonding in a-C:F film is closely related to the relative concentration of F atom in the plasma. The relationship between the precursor radicals and the deposition process of a-C:F film is discussed. It is pointed out that the gas flow rate of CHF3/(CHF3+C6H6) is an important factor in the a-C:F thin film fabrication.