Adsorption and Reaction of Si2H5 on Clean and H-Covered Si(100)-(2 x 1) Surfaces: A Computational Study

作者：Chen Hsin Tsung; Hwang Chi Chuan; Chiang Hsing Jung; Chang Jee Gong^*

来源：Journal of Physical Chemistry C, 2011, 115(31): 15369-15374.

DOI：10.1021/jp201997x

A spin-polarized density functional theory calculation was carried out to characterize the adsorption and decomposition of Si2H5 radical on the clean and H-covered Si(100)-(2 x 1) surface. The adsorption structures and energies of Si2H5, Si2H4, SiH3, and SiH2 on the Si(100)-(2 x 1) surface were predicted. It was found that Si2H6, Si2H4, SiH3, and SiH2 preferentially adsorb at the dimer_a, intrarow, dimer_b, and in-dimer sites, respectively. Potential energy profiles for the reactions of Si2H5 radical on the clean and H-covered Si(100)-(2 x 1) surfaces were constructed using the nudged elastic band (NEB) method. Calculations show that the Si2H5 radical can easily decompose to Si2H4(a), SiH3(a), SiH2(a), and H-(a) without any thermal activation, and the decomposition of Si(100)/Si2H5(a) -> Si2H4(a)/Si(100)/H-(a) may be the dominant mechanism on the clean Si(100) surface because of its low barrier and high exothermicity. The most likely mechanism for the reaction of Si2H5 on the H-covered Si(100)-(2 x 1) surface is the reaction of Si2H5(a) + H-(a) -> 2SiH(3(a)) with an exothermicity of 2.3 kcal/mol by passing a barrier of 59.9 kcal/mol.

• 出版日期2011-8-11