PLD方法制备的超硬非晶碳薄膜研究

Superhard amorphous carbon films fabricated by PLD

用脉冲激光沉积在不同条件下制备非晶碳超硬薄膜,研究了非晶碳超硬薄膜的表面形貌、结构、应力、硬度以及能谱等。原子力显微镜和扫描电镜图像显示,薄膜表面平整、致密且光滑,均方根粗糙度最大为0.877 nm。在高激光重复频率、高激光通量条件下,薄膜有很大的应力,致使膜层褶皱甚至破裂,小角X射线衍射表明薄膜为非晶态且最大残余应力达30 GPa以上,但300℃温度的原位退火可以有效降低残余应力;纳米压痕测试表明薄膜硬度大于20 GPa,弹性模量大于200 GPa;X射线光电子能谱表明薄膜中sp3的含量在39%～53%之间变化,并且与激光通量成正比。

Pulsed laser deposition（PLD） was used to plepare superhard amorphous carbon films. The films＇ surface appearance, structure, residual stress, hardness and XPS spectra were researched. AFM and SEM images show the film fabricated by PLD is flat, smooth and compact with the root mean square roughness less than 1nm （the maximum is 0. 877 nm）. Large residual stress of the films was measured by XRD, which would cause corrugation and break in the films prepared under high laser repetition frequency and fluence. However, the stress would relax under 300 ℃ annealing temperature. Nanoindentation test shows that hardness and Young＇s modulus of film were over 20 GPa and 200 GPa respectively. XPS tells that the content of sp^3 was between 39% and 53%, which was in direct proportion to laser fluence.