CVD金刚石薄膜(111)与(100)取向生长的热力学分析

用非平衡热力学耦合模型计算了CVD金刚石薄膜生长过程中C2H2与CH3浓度之比C2H2]/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（111）面和（100）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，C2H2]/CH3]逐渐升高，导致金刚石薄膜的形貌从（111）晶面转为（100）晶面。添加氧后C2H2与CH3浓度都将下降，但C2H2下降得更多，因而添加氧也使C2H2]/CH3]下降，从而有利于生长（111）晶面的金刚石薄膜。

Thermodynamic Analyses on (111) and (100) Facets Orientation Growth of CVD Diamond Film

CH3 and C2H2 are the dominant growth precursors during chemical vapor deposition diamond process. The ratio of C2H2 to CH3 concentration (C2H2]/CH3]) will affect the growth orientation of diamond film. In this paper C2H2]/CH3] as a function of substrate temperature is calculated under 4kPa pressure according to a non-equilibrium thermodynamic coupling model reported previously. Diamond (111) and (100) facets growth is discussed with the ratio of C2H2 to CH3 concentration under various substrate temperatures and CH4 concentrations. With the increase of substrate temperature or CH4 concentration, C2H2 ]/CH3] will rises. So the growth rate of diamond (111) facets controlled by C2H2 concentration is higher than that of diamond (100) facets controlled by CH3, and thus (100) facets appear. When oxygen is added to the gas phase for CVD diamond,C2H2 ]/CH3]will reduce, thus the growth of diamond film with (111) facets will be benefited. These results are well consistent with many experiments reported by other researchers.