激光轴向偏焦法平整化CVD金刚石膜

Laser flatting chemical vapor deposition diamond films by axial offset-focus

利用Nd:YAG型金刚石精密激光切割机,采用激光轴向偏焦法对化学气相沉积(CVD)法制备的金刚石膜表面进行扫描式平整化处理,利用扫描电子显微镜(SEM)、粗糙度仪和金相显微镜对平整化后的金刚石表面进行表征,研究了激光充电电压和焦点位置对扫描凹槽宽度和深度的影响,以及扫描间距对平整化效果的影响。研究结果表明:扫描凹槽宽度随激光充电电压的升高而增大;凹槽深度随激光充电电压的升高而增大,随偏焦量的增大而增大。激光轴向偏焦法对CVD金刚石膜进行平整化处理后,其粗糙度显著减小,利用氢等离子体对其表面进行刻蚀处理,能够有效去除表层石墨,从而达到理想的平整化效果。

Inhomogeneous chemical vapor deposition （CVD） diamond thick films are flatted by a Nd..YAG laser cutting ma chine with axial offset-focus. The influences of laser voltage, laser frequency and focus position on the diameter and depth of scan ning spot are researched respectively. In addition, the influence of scanning step on leveling result, which is characterized by a scanning electron microscope（SEM）, a roughmeter and a optical microscope, is studied. The results show that the increase of la ser voltage or focus offset contributes to the increase of depth of scanning spot, and the width of scanning groove will increase with the increase of laser voltage. The roughness of the CVD diamond films is reduced significantly after a flatting process, and the graphite on the surface of the diamond film due to laser processing is efficiently removed by etching of hydrogen plasma.