Atomic Layer Deposition of Ruthenium on a Titanium Nitride Surface: A Density Functional Theory Study

• Published in: Journal of physical chemistry. C Vol. 117; no. 38; pp. 19442 - 19453
• Main Authors: Phung, Quan Manh, Vancoillie, Steven, Pourtois, Geoffrey, Swerts, Johan, Pierloot, Kristine, Delabie, Annelies
• Format: Journal Article
• Language: English
• Published: Columbus, OH American Chemical Society 26.09.2013
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electron states; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Methods of electronic structure calculations; Physics; Theory and models of film growth; Vapor phase epitaxy; growth from vapor phase; Chemisorption; Atomic layer method; RBS; Ruthenium; Theoretical study; Titanium nitride; Boundary conditions; Crystal growth from vapors; Experimental study; Physisorption; Precursor; Atomic layer epitaxial growth; Experimental result; Adsorption; Growth mechanism; Reaction mechanism; Density functional method; Nanotechnology
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp405489w

Because of its excellent properties in nanotechnology applications, atomic layer deposition of ruthenium (Ru) has been the subject of numerous experimental studies. Recently, two different Ru precursors were compared for plasma-enhanced atomic layer deposition (PEALD) of Ru, and their reactivity was found to be different. Inhibition was observed for bis­(ethyl­cyclo­penta­dienyl)­ruthenium (Ru(EtCp)2), while nearly linear growth behavior was observed for (methyl­cyclo­penta­dienyl-pyrrolyl)­ruthenium (Ru(MeCp)Py). To understand this difference in reactivity, we investigate the adsorption of RuCp2 and RuCpPy (i.e., without substituents) on a TiN surface using calculations based on periodic boundary conditions density functional theory (DFT) combined with experiments based on Rutherford backscattering spectroscopy (RBS). The calculations demonstrate that the RuCpPy precursor chemisorbs on the TiN(100) surface while the RuCp2 precursor only physisorbs. We propose a reaction mechanism for the chemisorption of RuCpPy. The area density of the calculated RuCpPy surface species is compared with the experimental values from RBS. The impact of a H-plasma is also investigated. The DFT calculations and experimental results from RBS provide insight into the adsorption processes of the RuCpPy and RuCp2 precursors on the TiN(100) surface.