CVD金刚石薄膜亚表面层氢杂质对表面活化反应的影响

摘要/Abstract

摘要： 采用密度泛函理论平面波赝势法研究了氢杂质位于氢终止金刚石薄膜亚表面层中三种不同位点处时金刚石的结构变化,以及氢原子在三种金刚石薄膜表面上的吸附难易程度,并对表面活化反应进行了过渡态搜索以探究化学气相沉积(CVD)过程中金刚石薄膜亚表面层氢杂质对表面活化的影响。对比计算结果发现:生长过程中,亚表面层的氢杂质使其附近的金刚石结构产生了畸变,同时金刚石表面结构会对畸变程度产生影响。氢原子在含有氢杂质的三种金刚石薄膜上的吸附能与理想金刚石薄膜差异很小,但发生萃取反应产生活性位点的能垒比理想金刚石薄膜更低,这与亚表面层中的氢杂质使金刚石薄膜具有P型半导体特征这一现象有关。这一结果说明富氢反应气氛有利于活性位点的产生并以更高速率进行生长。

关键词: 金刚石薄膜, 氢杂质, 化学气相沉积, 密度泛函理论, 结构变化, 吸附能, 过渡态

Abstract: Density functional theory (DFT) plane wave pseudopotential method was used to study the structural changes of diamond when hydrogen impurities were located at three different sites in the subsurface of hydrogen terminated diamond films, and the difficulty of hydrogen atom adsorption on the three kinds of diamond films. Meanwhile, the transition state search of surface activation reaction was carried out. All work is to explore the influence of hydrogen impurities in the subsurface of diamond films on surface activation during chemical vapor deposition(CVD). The results show that: during the growth process, the structure of diamond near hydrogen impurities in subsurface is distorted, and the surface structure of diamond has an effect on the degree of distortion. The adsorption energy of hydrogen atom on the three kinds of diamond films containing hydrogen impurities are little different from that of ideal diamond film. However, the energy barrier of the active sites generated is lower than that of the ideal diamond films, which is related to the phenomenon that the hydrogen impurities in the subsurface make the diamond films have P-type semiconductor characteristics. The results show that the formation rate of surface active sites can increases as hydrogen impurities entering the subsurface of the film in hydrogen rich reaction atmosphere.

Key words: diamond film, hydrogen impurity, chemical vapor deposition, density functional theory, structural change, adsorption energy, transition state

中图分类号:

O781

简小刚, 唐金垚, 马千里, 胡吉博, 尹明睿. CVD金刚石薄膜亚表面层氢杂质对表面活化反应的影响[J]. 人工晶体学报, 2021, 50(2): 302-309.

JIAN Xiaogang, TANG Jinyao, MA Qianli, HU Jibo, YIN Mingrui. Influence of Hydrogen Impurities in the Subsurface of CVD Diamond Films on Surface Activation Reaction[J]. JOURNAL OF SYNTHETIC CRYSTALS, 2021, 50(2): 302-309.

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