C-H体系CVD金刚石薄膜取向生长的热力学分析

Thermodynamic Analyses on Orientation Growth of CVD Diamond Film in C H System

化学气相淀积金刚石薄膜过程中 ,CH3 和C2 H2 是金刚石生长的主要前驱基团。C2 H2 与CH3 浓度比 ( [C2 H2 ]/[CH3 ])的变化将影响金刚石薄膜的生长取向。用非平衡热力学耦合模型计算了C H体系CVD金刚石薄膜生长过程中C2 H2 浓度和CH3浓度随淀积条件的变化 ,并进一步获得了 [C2 H2 ]/[CH3 ]随衬底温度和CH4浓度的变化关系 ,从理论上探讨了金刚石薄膜 ( 1 1 1 )面和 ( 1 0 0 )面取向生长与淀积条件的关系。在衬底温度和CH4浓度由低到高的变化过程中 ,[C2 H2 ]/[CH3 ]逐渐升高 ,导致金刚石薄膜的形貌从 ( 1 1 1 )晶面转为 ( 1 0 0 )晶面。

CH 3 and C 2H 2 are the dominant growth precursors during chemical vapor deposition diamond process. The ratio of C 2H 2 to CH 3 concentration will affect the growth orientation of diamond film. The variations of C 2H 2 and CH 3 concentrations with the variations of deposition conditions during the growth of CVD diamond film in C H system are calculated by a non equilibrium thermodynamic coupling model. The dependences of the ratio of C 2H 2 to CH 3 concentrations ([C 2H 2]/[CH 3]) on substrate temperature and CH 4 concentration are also obtained. The relation between the growth orientation of (111) and (100) diamond films and the deposition conditions is discussed theoretically.[C 2H 2]/[CH 3] will rise with the increase of the substrate temperature or CH 4 concentration, which leads to the change of the diamond film topography from (111) to (100) face.