Enhancing the Crystallization and Properties of the SrRuO3 Electrode Film Grown by Atomic-Layer-Deposited SrO and Pulsed-Chemical Vapor-Deposited RuO2 through Al Substitution

Abstract

SrRuO3 (SRO) is a promisingelectrode materialfor thenext-generation dynamic random access memory (DRAM) capacitor. Thisstudy focuses on the properties of SRO electrode films grown by combiningthe atomic-layer deposition of SrO and pulsed-chemical vapor depositionof RuO2 component layers using Sr( (i) Pr3Cp)(2) ( (i) Pr3Cp = 1,2,4-trisisopropyl-cyclopentadienyl) and RuO4 precursors, respectively. Changes in the Ru concentration and electricalproperties of SRO electrode films during postdeposition annealing(PDA) for crystallization were examined in detail. SRO films werecrystallized after PDA in an O-2 atmosphere, but the Ruconcentration of SRO films was decreased due to volatile RuO4 formation. Also, the morphology of the film was degraded by agglomeration,which degraded the film & PRIME;s performance. A thin Al2O3 film was deposited on or inserted into Ru and SRO films,and its effects on Ru-loss and crystallization were experimentallyand theoretically investigated. The density functional theory calculationconfirmed that Al substituted with Ru (Al-Ru) in the SROfilm improved the crystallinity of cubic SRO. Thus, the Al2O3-layer-inserted or Al-substituted SRO films had a largergrain size, higher crystallinity, and improved surface morphologyand maintained a lower resistivity down to 25 nm (& SIM;1000 & mu;& omega;& BULL;cm).