双激光沉积锗掺杂类金刚石膜的实验研究

Experimental Research on Ge-doped Diamond-like Carbon Films Prepared by Double Laser Beams Deposition

提出了双激光沉积掺杂薄膜技术,利用准分子纳秒激光和飞秒激光分别烧蚀石墨和锗靶材,保持准分子纳秒激光的参数不变,而将飞秒激光的脉冲频率逐次由0提高至500 Hz,在硅基底上获得锗含量逐次增大的掺杂类金刚石膜。实验结果表明:随着锗掺杂量的提高,锗掺杂类金刚石膜的折射率略微增大,消光系数增大7.3倍;表面硬度呈近似的线性降低,降低幅度约为41.3%;内应力呈非线性减小并在某值趋于稳定,降低幅度约为78.1%。牢固度实验结果表明,锗掺杂量的提高可以增强类金刚石膜在基底上的附着性能,但不利于其对溶液的耐腐蚀性。研究结果为不同应用目的的掺杂类金刚石膜及其复合膜层的设计提供了实验基础,且研究方法具有很强的可扩展性,不仅仅限于实验所限薄膜范围。

Double laser beams deposition method for preparing doped thin film is designed. An excimer nanosecond laser and a femtosecond laser are used to ablate the graphite and germanium targets, respectively. The laser parameters of the excimer nanosecond laser keeps unchanged, and the repetition frequency of the femtoseeond laser changes from 0 to 500 Hz. Then the Ge-doped diamond-like carbon films with increased germanium concentration are prepared. The results of tests show that, with the improvement of germanium content, the refractive index of the Ge-doped diamond-like carbon film increases slightly, and the extinction coefficient increases 7.3 times. The surface-hardness of the films decreases by 41.3% linearly, while the inner-stress in the films reduces by 78.1% nonlinearly and tend to a steady value. The results of the fastness test show that the increasing of the germanium content can enhance the adhesion of the films on the germanium substrates, but reduce their corrupt-resistant against the circumstance. Because of the strong expansibility of the research method, the research results can not only offer the experiment base for the designs of doped diamond like carbon films or multiple doped diamond-like carbon films in different fields, hut also offer a new means of preparing other doped films for different purposes.