FCVA法沉积的超薄类金刚石薄膜的结构与热稳定性

Structural and Thermal Stabilities of Ultrathin Diamond-Like Carbon Films by Filtered Cathodic Vacuum Arc Deposition

采用FCVA方法沉积了厚度分别为2nm、5nm、10nm和30nm的类金刚石薄膜。在氩气保护下对类金刚石薄膜进行了180、300、400和600℃,保温6h的退火处理。用Raman光谱和宽光谱变角度椭偏仪研究了DLC薄膜的结构和热稳定性。实验结果表明,随着薄膜厚度增大,FCVA法沉积的DLC薄膜中的sp3键含量增加,薄膜热稳定性逐渐改善。当DLC薄膜的厚度为30nm时,薄膜中的sp3键含量达到最高值,薄膜具有最好的热稳定性。当退火温度为600℃时,厚度为2nm和5nm的DLC薄膜结构由非晶态转变为微晶态;厚度为10nm和30nm的DLC薄膜结构发生转变但仍保持非晶态。随着退火温度的升高,各个厚度的DLC薄膜的光学带隙Eg均先增大后减小。

The ultrathin diamond-like carbon （DLC） films,grown by filtered cathodic vacuum arc （FCVA） technique, were annealed in argon for 6 hours at different temperatures. The impacts of film growth and annealing conditions on the properties of the films were studied. The structure and thermal stabilities of the DLC films were characterized with Raman spectroscopy and ellipsometry spectroscopy and conventional optical probes. The results show that the film thickness strongly affects the sp^3 density and the thermal stability of the films. For instance, as the film thickness grows from 2nm to 30nm,the sp^3 density increases,peaking at 30urn with the highest thermal stability. And annealing at 600℃ turns the amorphous phase of the films, 2nm to 5nm thick, into nano-crystalline. However, the films, with thickness ranging from 10nm to 30nm,remain to be amorphous.As the annealing temperature rises up,the band gap, Eg,of the DLC films with different thickness increases first, and then decreases. Keywords Diamond-like carbon film, Structure,Thermal stability