Article pubs.acs.org/cm
Growth of Conductive SrRuO3 Films by Combining Atomic Layer Deposited SrO and Chemical Vapor Deposited RuO2 Layers Jeong Hwan Han, Woongkyu Lee, Woojin Jeon, Sang Woon Lee, and Cheol Seong Hwang* WCU Hybrid Materials Program, Department of Materials Science and Engineering and Inter-university Semiconductor Research Center, Seoul National University, Seoul 151-744, Korea
Changhee Ko and Julien Gatineau Air Liquide, 28, Wadai, Tsukuba-Shi, Ibaraki Pref., 300-4247, Japan ABSTRACT: SrRuO3 (SRO) film was deposited by sequential executions of atomic layer deposition of SrO and chemical vapor deposition of RuO2 layers at a low growth temperature of 230 °C using Sr(iPr3Cp)2, RuO4 precursors, and O2 gas. A wide range of Sr (Ru) concentration could be obtained by modulating the SrO/RuO2 subcycle ratio, and a high growth rate of ∼2.0 nm/supercycle was achieved with the stoichiometric SRO composition. The as-deposited SRO film was amorphous, and crystallized SRO film was obtained by post deposition annealing in N2 ambient at temperatures ranging from 600 to 700 °C. Crystallized SRO film was adopted as a seed layer for the in situ crystallization of ALD SrTiO3 (STO) film for application to capacitors for next generation dynamic random access memory. Consequently, a crystalline STO film was grown on crystallized SRO in the as-deposited state, and the dielectric constant of the STO film was largely improved compared to that of the amorphous STO, from 12 to 44. KEYWORDS: SrRuO3, RuO4, Sr(iPr3Cp)2, SrTiO3, DRAM, chemical vapor deposition, atomic layer deposition significantly as reported by Lee et al. and Pawlak et al.11,12 They also reported that as-deposited STO films grown by ALD on Ru or TiN electrodes usually have amorphous structure due to its low growth temperature of
