Size Dependent Effects in Nucleation of Ru and Ru Oxide Thin Films by Atomic Layer Deposition Measured by Synchrotron Radiation X-ray Diffraction

作者：Methaapanon Rungthiwa; Geyer Scott M; Brennan Sean; Bent Stacey F^*

来源：Chemistry of Materials, 2013, 25(17): 3458-3463.

DOI：10.1021/cm401585k

• Ru
• RuO2
• XRD
• nucleation
• atomic layer deposition

The crystal structure and growth behavior of Ru and RuO2 on amorphous SiO2 are measured during atomic layer deposition (ALD) by ex situ and in situ high-resolution synchrotron radiation X-ray diffraction (XRD). In situ XRD studies suggest that RuO2 films grown by bis(2,4-dimethylpentadienyl)ruthenium, Ru(DMPD)(2), and oxygen at low temperature do not initially nucleate as RuO2. Despite large oxygen exposures during the ALD process, the initial nuclei form as hcp Ru. Then, after higher numbers of ALD cycles, crystalline rutile RuO2 begins to appear. The results suggest that a critical Ru nucleus size is required to initiate the growth of RuO2. We speculate that a rate limiting step in the oxidation of Ru, possibly the formation of subsurface oxygen, is dependent upon the size of the Ru nuclei. Although the hcp Ru films are textured with a (002) preference in the growth direction, the rutile RuO2 films once they nucleate have no preferential orientation.

• 出版日期2013-9-10