H原子与SiFn（n=1～4）反应机理的理论研究  

Theoretical Study on the Reaction Mechanism of H Atom and SiFn （n=1～4）

作　　者：马琳[1] 孙仁安[1] 官文佳[1] 王艳丽[1] 

机构地区：[1]辽宁师范大学化学化工学院,辽宁大连116029

出　　处：《辽宁师范大学学报（自然科学版）》2006年第3期321-324,共4页Journal of Liaoning Normal University:Natural Science Edition

基　　金：辽宁省教育厅资助项目(990321076)

摘　　要：采用密度泛函理论（DFT）B3LYP方法，在6-311G（2d，2p）基组下，研究了H原子与SiFn（n=1～4）的反应历程．通过振动频率和内察反应坐标（IRC）分析，对过渡态进行了确认．在QCISD／6-311G（2d，2p）水平上进行了单点能计算，并进行了零点能校正．结果表明：在单重态下H原子倾向于添加到Si原子上，而二重态和三重态下H原子倾向于夺取F原子．在H原子一步步夺取F原子的反应过程中，主要产物为SiHF3，Si原子在副反应中生成．由于副反应能垒较高，在真实体系中生成Si原子很困难，由此我们推断实际反应中加入的衬底起到了关键作用．The reaction mechanism of H atom and SiFn（n= 1～4） has been studied using DFT. The geometries of reactions, transition state and products have been optimized at the B3LYP level with 6- 311g（2d,2p） basis set. The frequency analysis and intrinsic reaction coordinate calculation were used to confirm the transition state. The total energies and reaction barriers were calculated at QCISD/6- 311g（2d,2p） level and corrected by the zero-point energy. As a result, addition of a H atom is favored at the singlet state, while abstraction of a F atom is favored at the doublet and triplet state. In the process of H atom capturing F atom from SiF4 step by step, the main product is SiHF3 ,and Si atom appears in secondary reactions. It is difficult to find Si atom in the gas mixture, so we conclude that the ,mderlay could play an important role in the PECVD.

关 键 词：SiFn 反应机理 过渡态 DFT 

分 类 号：O641[理学—物理化学]