C-H-F氛围下金刚石薄膜的低温CVD生长过程分析

Analysis of low-temperature CVD growth process of diamond films in C-H-F atmosphere

基于第一性原理的密度泛函理论对C-H-F氛围下低温CVD金刚石薄膜的生长过程进行仿真分析,计算H、F原子在氢终止金刚石表面发生萃取反应的吸附能、反应热与反应能垒,并分析CF_(3)、CF_(2)、CF 3种生长基团在带有活性位点基底上的吸附。结果表明:与H原子相比,F原子更容易在氢终止金刚石表面萃出H,并以HF形式脱附,且在C-H-F氛围下有利于在低温时产生更多的活性位点;CF_(3)、CF_(2)、CF基团在吸附后的结构和吸附能绝对值都更有利于金刚石相的生成,适当提高CF_(3)、CF_(2)、CF基团的浓度有助于实现金刚石相的更高速率生长。

To better understand the growth mechanism of diamond films via low-temperature chemical vapor deposition in a C-H-F atmosphere,this paper employed density functional theory based on first principle.It calculated the adsorption energy,reaction heat,and reaction energy barrier of H and F atoms undergoing extraction reactions on the hydrogen-terminated diamond surface.Additionally,the analysis included the adsorption of CF_(3),CF_(2),and CF growth groups on the active site substrate.The results show that compared with H atoms,F atoms are more likely to extract H from the surface of hydrogen terminated diamond and desorb it in the form of HF.This process is advantageous for generating more active sites at low temperatures in a C-H-F atmosphere.Both the structure and the absolute value of the adsorption energy of CF_(3),CF_(2),and CF groups are more favorable for the generation of the diamond phase after adsorption.Increasing the concentration of CF_(3),CF_(2),and CF growth groups appropriately can facilitate the growth of diamond phase at a higher rate.