Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Using a Zero-Oxidation State Precursor

• Published in: Chemistry of materials Vol. 29; no. 3; pp. 1107 - 1115
• Main Authors: Austin, Dustin Z, Jenkins, Melanie A, Allman, Derryl, Hose, Sallie, Price, David, Dezelah, Charles L, Conley, John F
• Format: Journal Article
• Language: English
• Published: American Chemical Society 14-02-2017
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.6b04251

Atomic layer deposition (ALD) processes are reported for ruthenium (Ru) and ruthenium oxide (RuO2) using a zero-oxidation state liquid precursor, η4-2,3-dimethylbutadiene ruthenium tricarbonyl [Ru­(DMBD)­(CO)3]. Both ALD Ru and RuO2 films were deposited using alternating N2 -purge-separated pulses of Ru­(DMBD)­(CO)3 and O2. ALD Ru metal films were deposited via short (2 s) pulses of O2. Ru films have an ALD temperature window from 290 to 320 °C with a GPC of 0.067 nm/cycle and a negligible nucleation delay on SiO2. Ru films show a strong hexagonal crystal structure with low resistivity of approximately 14 μΩ cm at 320 °C. RuO2 films were deposited using longer (20 s) pulses of either molecular O2 or O2 plasma. RuO2 films deposited via thermal ALD using molecular O2 have a temperature window from 220 to 240 °C with a GPC and nucleation delay on SiO2 of 0.065 nm/cycle and 35 cycles, respectively. Thermal ALD RuO2 films show a distinct rutile phase microstructure with a resistivity of approximately 62 μΩ cm. In comparison to thermal ALD, the PEALD RuO x films show a lower growth rate and higher nucleation delay of 0.029 nm/cycle and 76 cycles, respectively. PEALD RuO x films also exhibit less distinct crystallinity and a higher resistivity of 377 μΩ cm.