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近年来 ,有机金属气相外延 (OMVPE)技术已经成为高纯度半导体制备的最为广泛的方法。深入理解OMVPE的反应机制 ,对于OMVPE反应前体的选择、沉积系统的设计以及对掺杂剂的控制等都显得很重要。但是 ,由于反应的复杂性 ,反应中大量不稳定中间体的产生 ,实验研究昂贵而困难 ;而且由于反应前体热力学和动力学数据的匮乏 ,也给实验结果的解释带来很大困难。因此 ,从量子力学基本原理出发 ,从理论上对OMVPE进行研究 ,获得化合物的热力学和动力学数据 ,以及得到OMVPE过程的微观化学反应图象 ,具有重要意义。近年来 ,密度泛函理论 (DFT)已经发展成为一种对分子体系电子结构计算较为成熟的方法。大量研究证明 ,只要选择合适的交换相关能泛函 ,DFT是研究分子性质的有力工具 ,能够得到可信的结果。Me3 In和PH3 是制备Ⅲ Ⅴ半导体的重要反应前体或掺杂剂。已有实验证据表明在PH3 存在的条件下 ,Me3 In与PH3 会生成Me3 In·PH3 中间体 ,并显著改变Me3 In的热分解—沉积反应机制。但是 ,迄今还没有对该中间体的热力学性质和反应性能作祥细研究。本文利用密度泛函方法对Me3 In·PH3 进行理论研究 ,得到了一些有意义的结果。其主要计算结果包括。( 1 )通过全优化计算得到Me3 In·PH3 加合物的平衡几何构型 ,基本振动频?
In recent years, organic metal vapor phase epitaxy (OMVPE) technology has become the most widely used method for the preparation of high purity semiconductors. In-depth understanding of the reaction mechanism of OMVPE is very important for the choice of OMVPE reaction precursor, the design of deposition system and the control of dopants. However, due to the complexity of the reaction, the generation of a large number of unstable intermediates in the reaction is expensive and difficult to study. Moreover, due to the lack of thermodynamic and kinetic data, it is very difficult to explain the experimental results. Therefore, starting from the basic principles of quantum mechanics, it is of great significance to theoretically study OMVPE, to obtain thermodynamic and kinetic data of the compounds and to obtain microscopic chemical reaction images of the OMVPE process. In recent years, density functional theory (DFT) has developed into a more mature method of calculating the electronic structure of molecular systems. Numerous studies have shown that DFT is a powerful tool for studying the properties of molecules and can yield credible results as long as the proper exchange-related functional theory is chosen. Me3 In and PH3 are important precursors or dopants for the preparation of III Ⅴ semiconductors. Experimental evidence shows that under the condition of PH3, Me3In and PH3 will generate Me3In · PH3intermediate and significantly change the mechanism of thermal decomposition-deposition reaction of Me3In. However, to date, no detailed studies have been conducted on the thermodynamic properties and reactivity of this intermediate. In this paper, the density functional theory of Me3 In · PH3 theoretical study, and some meaningful results. The main results include. (1) Calculate the equilibrium geometry of Me3In · PH3 adduct through full optimization calculation,