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

Abstract

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 CF3, CF2, 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 CF3, CF2, and CF groups are more favorable for the generation of the diamond phase after adsorption. Increasing the concentration of CF3, CF2, and CF growth groups appropriately can facilitate the growth of diamond phase at a higher rate.

Keywords

• cvd diamond film
• fluorine
• deposition mechanism
• first-principles
• adsorption
• surface chemical reaction