Growth of Conductive SrRuO₃ Films by Combining Atomic Layer Deposited SrO and Chemical Vapor Deposited RuO₂ Layers

SrRuO 3 (SRO) film was deposited by sequential executions of atomic layer deposition of SrO and chemical vapor deposition of RuO 2 layers at a low growth temperature of 230 °C using Sr( i Pr 3 Cp) 2, RuO 4 precursors, and O 2 gas. A wide range of Sr (Ru) concentration could be obtained by modulating the SrO/RuO 2 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 N 2 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 SrTiO 3 (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.