Photochemically Induced Metallization of Surface Silicon Using Dinuclear Metal Carbonyl Compounds. Anchoring of Ruthenium to a Si(111) Surface through Covalent Ru−Si Bond Formation

Abstract

Near-UV irradiation of hydrogen-terminated Si(111) wafers with the ruthenium-ruthenium bonded dinuclear compounds Cp 2 Ru 2 (CO) 4 (where Cp ) η 5 -MeC 5 H 4 , η 5 -C 5 Me 5 ) and [HB(pz) 3 ] 2 Ru 2 (CO) 4 [where HB(pz) 3 ) hydrotris(1-pyrazolyl)borate] in benzene solution at room temperature leads to the covalent attachment of CpRu(CO) 2 and HB(pz) 3 Ru(CO) 2 moieties to surface silicon sites on the wafer. ATR FTIR, XPS, and RBS data support the proposed Ru-Si bond formation as the dominant mode of wafer metallization. The surface area coverage of these ruthenized wafers is limited by the size the mononuclear ruthenium moiety that is attached to the Si anchor. A plausible reaction sequence involving the photochemically generated ruthenium-centered radicals CpRu(CO) 2 and [HB(pz) 3 ]Ru(CO) 2 that both activate the hydrogen-terminated Si(111) surface and combine with the resulting silicon radicals is presented and discussed.

Area-Selective Atomic Layer Deposition of Ruthenium Using a Novel Ru Precursor and H2O as a Reactant

“…In previous studies that analyzed adsorption on Si surfaces of heteroleptic transient metal compounds, such as (tBu-allyl)Co(CO) 3 and R 2 Ru 2 (CO) 4 [where R is C 5 H 4 Me, C 5 (Me) 5 , or hydrotris(1-pyrazolyl)borate], the formation of direct surface-metal bonds was suggested as the initial reaction product. 46,47 48 it is expected that the kinetic constants for the precursor chemisorption on the H−Si surface would be greater than those on the OH−Si surface. This explains how nucleation of Ru can readily occur on H−Si, while OH−Si shows significant nucleation delay.…”

“…To understand the preference of initial Ru nucleation on H-terminated Si compared to the SiO 2 substrate, DFT calculations are performed to compare the chemisorption of the precursor on H–Si and OH-terminated Si substrates (Figure ). In previous studies that analyzed adsorption on Si surfaces of heteroleptic transient metal compounds, such as ( t Bu-allyl)­Co­(CO) 3 and R 2 Ru 2 (CO) 4 [where R is C 5 H 4 Me, C 5 (Me) 5 , or hydrotris­(1-pyrazolyl)­borate], the formation of direct surface-metal bonds was suggested as the initial reaction product. , Therefore, it was assumed that the azaallyl {N­( t Bu)–C­(H)–C­( i Pr)} ligand of the T-Rudic precursor would be hydrogenated by the H atoms on the surface, resulting in the formation of an enamine {N(H)( t Bu)­C(H)C(H)( i Pr)­} ligand bridging two Ru atoms, each of which is directly bonded to the surface atoms (Si or O). As the T-Rudic precursor possesses two Ru atoms, it was assumed that it would react with two neighboring surface sites.…”

Understanding adsorption geometry of organometallic molecules on graphite

“…1 c, the peak at 465.3 eV corresponding to Ru 3p 3/2 was observed in the case of dried Cp * Ru(CH 3 CN) 3 PF 6 solution on the glass substrate (blue). Meanwhile, the presence of Ru 3p 3/2 in the dropped Cp * RuL 3 PF 6 solution on the graphene (or HOPG substrate), was confirmed by the peaks at 462.3 eV, which induced a coordinative reaction between the Cp * Ru + fragments and the graphene surface (green and red) 32 – 34 . This peak shift is important for explaining the reaction between Cp * Ru + and the HOPG surface.…”

Understanding Adsorption Geometry of Organometallic Molecules on Graphene

“…Meanwhile, the presence of Ru 3p 3/2 in the dropped Cp * RuL 3 PF 6 solution on the graphene (or HOPG substrate), was con rmed by the peaks at 462.3 eV, which induced a reaction between the Cp * Ru + fragments and the graphene surface (gray and dark gray). [32][33][34] This peak shift is important for explaining the reaction between Cp * Ru + and the HOPG surface. The Ru + atoms in [Cp * Ru(CH 3 CN) 3 ] + and Cp * Ru + -graphene have different atomic environments.…”