Photochemical CVD of Ru on functionalized self-assembled monolayers from organometallic precursors.
Chemical vapor deposition (CVD) is an attractive technique for the metallization of organic thin films because it is selective and the thickness of the deposited film can easily be controlled. However, thermal CVD processes often require high temperatures which are generally incompatible with organic films. In this paper, we perform proof-of-concept studies of photochemical CVD to metallize organic thin films. In this method, a precursor undergoes photolytic decomposition to generate thermally labile intermediates prior to adsorption on the sample. Three readily available Ru precursors, CpRu(CO)2Me, (η3-allyl)Ru(CO)3Br, and (COT)Ru(CO)3, were employed to investigate the role of precursor quantum yield, ligand chemistry, and the Ru oxidation state on the deposition. To investigate the role of the substrate chemistry on deposition, carboxylic acid-, hydroxyl-, and methyl-terminated self-assembled monolayers were used. The data indicate that moderate quantum yields for ligand loss (φ ≥ 0.4) are required for ruthenium deposition, and the deposition is wavelength dependent. Second, anionic polyhapto ligands such as cyclopentadienyl and allyl are more difficult to remove than carbonyls, halides, and alkyls. Third, in contrast to the atomic layer deposition, acid-base reactions between the precursor and the substrate are more effective for deposition than nucleophilic reactions. Finally, the data suggest that selective deposition can be achieved on organic thin films by judicious choice of precursor and functional groups present on the substrate. These studies thus provide guidelines for the rational design of new precursors specifically for selective photochemical CVD on organic substrates.
Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA.
Kelsea R
KR
Johnson
Department of Materials Science and Engineering, University of Texas at Dallas, 800 W. Campbell Rd, Richardson, Texas 75080, USA.
Paul
P
Arevalo Rodriguez
Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA.
Christopher R
0000000280039444
CR
Brewer
Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA.
Joseph A
JA
Brannaka
Department of Materials Science and Engineering, University of Texas at Dallas, 800 W. Campbell Rd, Richardson, Texas 75080, USA.
Zhiwei
Z
Shi
Department of Materials Science and Engineering, University of Texas at Dallas, 800 W. Campbell Rd, Richardson, Texas 75080, USA.
Jing
J
Yang
Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, USA.
Bryan
0000000330797367
B
Salazar
Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA.
Lisa
0000000157915146
L
McElwee-White
Department of Materials Science and Engineering, University of Texas at Dallas, 800 W. Campbell Rd, Richardson, Texas 75080, USA.
Amy V
AV
Walker