掺氮类金刚石薄膜激光退火的Raman光谱研究

Raman analysis of laser annealed amorphous nitrogen doped carbon film

采用功率密度分别为 30 0、75 0和 15 0 0W /mm2 的氩离子激光器 ,对由射频等离子化学气相沉积 (RF CVD)法制备的掺氮类金刚石薄膜进行了激光退火处理。并用傅立叶红外吸收光谱和显微Raman等手段 ,对所得样品进行了研究。结果表明 :C—N键比C—H键更为稳定 ,一方面氮原子的引入制约了C—H键的生成 ,在激光退火中减少了因C—H键分解而引起薄膜的石墨化 ;另一方面生成的C—N键不易受热分解 ;因此随着氮含量的增加 ,薄膜中C—N成分增加 。

Micro-Raman spectrometer was used to study nitrogen doped amorphous hydrogenated carbon a-C: H(N) films, which were readily annealed by a focused argon ion (514.5 nm) laser operating at the power density of 300, 750 and 1500 W/mm2 respectively. The analytical results show that nitrogen atoms in the films as C-N bond form limit C-H bonds to form due to that the formation energy of C-N bond is higher than that of C-H bond. So the C-H bonds in a-C: H film are easy to decompose and cause graphitization of film during laser annealing. C-N bonds are hardly to decompose during laser annealing so that it can be considered that a-C: H(N) film has higher thermal stability with the increase of its nitrogen content.