超短脉冲准分子激光淀积类金刚石薄膜的实验研究

Deposition of Diamond Like Carbon Film by Ultrashort Pulsed Excimer Laser

利用ＫｒＦ超短脉冲激光器（２４８ｎｍ，５００ｆｓ，１０ｍＪ）开展了超短脉冲激光淀积类金刚石薄膜的实验研究，薄膜生长速率０．０２ｎｍ／ｐｕｌｓｅ，厚度０．５～０．６μｍ，显微硬度５５ＧＰａ，光学透过率优于９０％（５８０～２０μｍ）。采用等离子体的时间－空间分辨的发射光谱技术，给出了等离子体的粒子成份以及等离子体的时间－空间的演化图像，以及在不同激光参数条件下等离子体特性的变化，发现超短脉冲激光的等离子体有能量高、持续时间短（高通量）的特点，适合类金刚石薄膜的淀积并有制备其他非晶态结构和纳米相薄膜材料的潜力。利用自行研制的离子探针原位诊断了在成膜条件下的粒子流的特性及其随激光参数等实验条件的变化，其结果与发射光谱非常自洽。比较了不同激光参数条件下，等离子体特性、粒子流特性及淀积类金刚石薄膜的结构和性能的变化，并对短脉冲激光和靶相互作用过程和激光等离子体淀积类金刚石成膜的机理进行了讨论，为进一步提高成膜质量走向实用化打下基础。

Diamond like carbon (DLC) films have been deposited by ultrashort pulsed excimer laser (KrF 248 nm, 500 fs, 10 mJ). The film depth is 0.5 μm, the growth rate is 0.3￣0.4 μm/h, the microhardness is 55 GPa, the optical tansimittance is better than 93%(580 nm￣3 μm)。 With the temporal and spatial emission spectra, the property of plasma plume generated by the ultrashort pulsed laser and its variation with the laser parameters have been investigated. The velocity of plasma plume is very high (1×10 7 cm/s), the duration is very short (200￣300 ns), so the plasma flux is intensive and this is suitable to deposit DLC and other metestable material. We have used the ion probe to measure the plasma ion flux, the result is consistent with that of the emission spectra. Under different laser parameter, DLC films were deposited and the effect of laser parameter and plasma flux on the deposited film have been compared. The characteristic of the interaction of ultrashort pulse with the target and the formation of DLC by laser plasma have been discussed.