We describe a new family of platinum complexes that show great promise as improved precursors for the chemical vapor deposition (CVD) of thin films. These compounds contain ω-enyl chelates with an alkyl group at one end and an alkene at the other. These ligands are chemically related to allyl groups, which are well known to form highly volatile binary compounds with most of the transition elements, except that the alkyl and alkene functional groups are separated. We expect that these ω-enyl chelates will bind more weakly to transition metals (and transition metal surfaces) than many ligands commonly employed in CVD precursors, such as cyclopentadienyl groups. As a result, there may be less incorporation of undesired carbon impurities into a CVD deposit. One representative example of this new class of compounds is cis-bis(η2,η1-2,2-dimethylpent-4-en-1-yl)platinum: this compound is a liquid under ambient conditions, has a very high vapor pressure, can be stored at -20 °C indefinitely (and for long times at room temperature), and is air- and moisture-stable. Preliminary assessments suggest that this compound offers advantages over other Pt CVD precursors, including (MeC5H4)PtMe3 (which is air sensitive), diallylplatinum, (which is thermally unstable), Pt(acac)2 (which has a low vapor pressure), and Pt(PF3)4 (which is hard to make and generates toxic byproducts). We will also describe several related compounds with other ω-enyl ligands and with other metals, including some highly volatile iridium and rhodium compounds, and studies of the thermolysis mechanism.

New platinum complexes for use in platinum CVD

254th National Meeting (2017)

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