Computational Study for Reactions of H Atoms with Adsorbed SiH3 and Si2H5 on H-Covered Si(100)-(2 × 1) Surface

Abstract

Density functional theory calculations with spin-polarization effect were employed to illustrate the adsorption of SixHy (x = 1–2; y = 1–5) species and the reactions of H atoms with adsorbed SiHx (x = 1–3) and Si2H5 species on the H-covered Si(100)-(2 × 1) surface. The configurations and energies of these adsorbates were elucidated. It was found that H vacancy sites can be easy created by SiH3 and Si2H5 radicals with small barriers (2.1 and 1.6 kcal/mol for SiH3 and Si2H5, respectively). The Si2H5, Si2H4, SiHSiH3, SiH3, SiH2, SiH, and Si radials interact with the surface more forcefully than the Si2H6 and SiH4 molecules. Potential energy surfaces for the reaction mechanisms of H + SiHx(a) and H + Si2H5(a) were mapped by using the nudged elastic band method. The calculation results demonstrate that the most favorable pathway is hydrogen abstraction leading to the production of H2 and SixHy (x = 1–2; y = 0–4) because of their low barriers and high exothermicities. Rate constant calculations were performed to study the kinetic behavior for simulation of silicon thin-film growth by chemical vapor deposition processes.