Atomic Layer Deposition of Ru Thin Films Using a New Beta-Diketonate Ru Precursor and NH3 Plasma as a Reactant

• Published in: Journal of nanoscience and nanotechnology Vol. 15; no. 11; p. 8472
• Main Authors: Jung, Jae-Hun, Lee, Seung-Joon, Lee, Hyun-Jung, Lee, Min Young, Cheon, Taehoon, Bae, So Ik, Saito, Masayuki, Suzuki, Kazuharu, Nabeya, Shunichi, Lee, Jeongyeop, Kim, Sangdeok, Yeom, Seungjin, Seo, Jong Hyun, Kim, Soo-Hyun
• Format: Journal Article
• Language: English
• Published: United States 01.11.2015
• ISSN: 1533-4899
• DOI: 10.1166/jnn.2015.11452

Ruthenium (Ru) thin films were grown on thermally-grown SiO2 substrates by plasma enhanced atomic layer deposition (PEALD) using a sequential supply of a new betadiketonate Ru metallorganic precursor, dicarbonyl-bis(5-methyl-2,4-hexanediketonato) Ru(II) (C16H22O6Ru) with a high vapor pressure and NH3 plasma as a reactant at the substrate temperature ranging from 175 and 310 degrees C. A self-limited film growth was confirmed at the deposition temperature of 225 degrees C and the growth rate was 0.063 nm/cycle on the SiO2 substrate with very short number of incubation cycles (approximately 10 cycles). The resistivity of PEALD-Ru films was dependent on the microstructural features characterized by grain size and crystallinity, which could be controlled by varying the deposition temperature. Ru film with the resistivity of -20 μΩ-cm and high density of 11.5 g/cm3 was obtained at the deposition temperature as low as 225 degrees C. It formed polycrystalline structure with hexagonal-close-packed phase that was confirmed by X-ray diffractometry and transmission electronic microscopy analysis. Step coverage of PEALD-Ru film deposited with the optimum condition was good (-75%) at the very small-sized trench (aspect ratio: -4.5 and the top opening size of 25 nm).