| AVS 56th International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session I and Mort Traum Finalists |
| Presenter: | J.C.F. Rodríguez-Reyes, University of Delaware |
| Authors: | J.C.F. Rodríguez-Reyes, University of Delaware A.V. Teplyakov, University of Delaware |
| Correspondent: | Click to Email |
Fundamental studies focused on understanding the key surface processes that introduce contaminants into a growing film are essential for achieving a contaminant-free thin film deposition. In the case of the metal alkylamide precursor Ti[N(CH3)2]4, we have obtained experimental evidence of two chemical reactions on a Si(100) surface that explain the uncontrolled incorporation of carbon during deposition, namely a surface attachment through a ligand and a feasible C-H bond scission on the surface. For both reactions, the nitrogen p-orbital in the alkylamide precursor plays a significant role, not only favoring the interaction of a N atom with electron-deficient surface sites, but also weakening anti-periplanar C-H bonds. The realization of the important role that the heteroatom in the ligand plays during surface reactions prompted us to start a comprehensive computational investigation of N-containing and O-containing metalorganic precursors, such as amidinates, guanidinates, alkoxides and acetonates. In addition, we consider metal alkyls and cyclopentadienyl precursors. An effective comparison of the surface reactivity of these compounds and their ability to adsorb and decompose on a surface is achieved by simulating the reactions on a silicon surface cluster model using the same methods. Our results corroborate the model established for the alkylamide precursors, where metalorganic precursors adsorb preferentially through the formation of a N- or O- dative bond to the surface. However, further decomposition mechanisms are less favorable for certain types of precursors, such as amidinates and guanidinates, where the p-orbital of the N atoms is delocalized and therefore does not favor the scission of nearby C-H bonds. Oppositely, alkylamides, alkoxides and acetonates are found to readily decompose on the surface. When heteroatoms are absent (e.g. in the case of cyclopentadienyls) adsorption is a significantly less favorable process and decomposition pathways leading to carbon incorporation are less feasible than for other compounds. This investigation is intended to set a ground work for future investigations devoted to understanding and controlling contamination mechanisms during film deposition.