Chemical Vapor Deposition of Ruthenium and Osmium Thin Films Using (Hexafluoro-2-butyne)tetracarbonylruthenium and -osmium

The known mononuclear ruthenium complex Ru(hfb)(CO)₄, where hfb stands for hexafluoro-2-butyne, has a vapor pressure of 1.5 Torr at 25 °C and forms reflective ruthenium thin films by chemical vapor deposition (CVD) using H₂ carrier gas with a growth rate of 21 nm/min at 500 °C. The resistivity of a ruthenium film having a grain size of 60 nm was 22 µΩ cm. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analyses indicated that the films were pure, polycrystalline ruthenium (<1% C, 0, or F). Scanning electron microscopy and XRD analyses revealed that the deposition temperature and the presence of H₂ gas affect the microstructure and the resistivity of the films. Os(hfb)-(CO)₄ afforded polycrystalline osmium thin films using H₂ as a carrier gas. A growth rate of 14 nm/min, a resistivity of 81 µΩ cm, and a grain size of 20 nm were found for depositions conducted at 600 °C. XPS analysis indicated that the film consists of 84% Os, 7% O, and 9% C. The new dinuclear metal complexes M₂[µ-η¹:η¹:η⁴:-C₄(CF₃)₄] (CO)₆ (M = Ru, Os) were formed from M(hfb) (CO)₄ during the CVD processes conducted in the absence of H₂ gas at the temperature range 150–300 °C.