Selective Atomic Layer Deposition Mechanism for Titanium Dioxide Films with (EtCp)Ti(NMe2)3: Ozone versus Water
The need for the conformal deposition of TiO2 thin films in device fabrication has motivated a search for thermally robust titania precursors with noncorrosive byproducts. Alkylamido-cyclopentadienyl precursors are attractive because they are readily oxidized, yet stable, and afford environmentally mild byproducts. We have explored the deposition of TiO2 films on OH-terminated SiO2 surfaces by in situ Fourier transform infrared spectroscopy using a novel titanium precursor [(EtCp)Ti(NMe2)3 (1), Et = CH2CH3] with either ozone or water. This precursor initially reacts with surface hydroxyl groups at ≥150 °C through the loss of its NMe2 groups. However, once the precursor is chemisorbed, its subsequent reactivities toward ozone and water are very different. There is a clear reaction with ozone, characterized by the formation of monodentate formate and/or chelate bidentate carbonate surface species; in contrast, there is no detectable reaction with water. For the ozone-based ALD process, the surface formate/c...
Joseph P. Klesko; Rezwanur Rahman; Aaron Dangerfield; Charith E. Nanayakkara; Thomas L’Esperance; Daniel F. Moser; L. Fabián Peña; Eric C. Mattson; Charles L. Dezelah; Ravindra K. Kanjolia; Yves J. Chabal
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Poly-ADP-ribosylation (PARylation) is a protein posttranslational modification (PTM) that is critically involved in many biological processes that are linked to cell stress responses. It is catalyzed by a class of enzymes known as poly-ADP-ribose polymerases (PARPs). In particular, PARP1 is ... more
This review focuses on the type A cytochrome c oxidases (CcO), which are found in all mitochondria and also in several aerobic bacteria. CcO catalyzes the respiratory reduction of dioxygen (O2) to water by an intriguing mechanism, the details of which are fairly well understood today as a r ... more
Rohm and Haas Powder Coatings is delighted to announce that its Reading, Pennsylvania, facility is the first site in the world to receive the RCMS® Site Certification awarded by the American Chemical Council (ACC).
When Raj Gupta, Chairman and CEO of Rohm and Haas Company, became Chairman ... more