Energy barriers for trimethylaluminum reaction with varying surface hydroxyl density

• Published in: Applied surface science 2011-10, Vol.258 (1), p.225-229
• Main Authors: Kim, Dae-Hee, Baek, Seung-Bin, Kim, Yeong-Cheol
• Format: Article
• Language: English
• Subjects: Atomic layer deposition; Barriers; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Density; Density functional theory; Energy use; Exact sciences and technology; Hydrogen bonds; Physics; Silicon; Surface hydroxyl density; Trends; Trimethylaluminum
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2011.08.035

Energy variation is shown for TMA reaction to produce a DMA group and CH 4 on the fully OH-terminated a-SiO 2 (0 0 1) surface. TMA is less attracted to –OH due to its attraction to a neighboring –OH, compared to the fully OH-terminated Si (0 0 1) surface. [Display omitted] ► Interactions of a trimethylaluminum molecule with varying surface hydroxyl density. ► Four different surfaces with varying surface hydroxyl density. ► Strongly affected energy barriers for TMA reaction with hydroxyl by bond making and bond breaking between them. Energy barriers for trimethylaluminum (TMA) reaction with varying surface hydroxyl (–OH) density were investigated using density functional theory. When the surface –OH density increased from 0 to 6.8/nm 2 on Si (0 0 1) surfaces, the energy barrier for TMA reaction with the surfaces decreased due to attractive interactions between TMA and –OH. When the surface –OH density further increased to 9.2/nm 2 on a-SiO 2 (0 0 1) surfaces, however, the trend was reversed. This was because the attractive interactions between TMA and –OH were decreased due to the attractive interactions of –OH's themselves via hydrogen bond at this high surface –OH density.