Atomic Layer Deposition of SrTiO3 Films with Cyclopentadienyl-Based Precursors for Metal鈥揑nsulator鈥揗etal Capacitors

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• 作者：Woongkyu Lee ; Jeong Hwan Han ; Woojin Jeon ; Yeon Woo Yoo ; Sang Woon Lee ; Seong Keun Kim ; Chang-Hee Ko ; Clement Lansalot-Matras ; Cheol Seong Hwang
• 刊名：Chemistry of Materials
• 出版年：2013
• 出版时间：March 26, 2013
• 年：2013
• 卷：25
• 期：6
• 页码：953-961
• 全文大小：517K
• 年卷期：v.25,no.6(March 26, 2013)
• ISSN：1520-5002

文摘

The characteristics of the atomic layer deposition (ALD) of SrTiO₃ (STO) films were examined for metal鈥搃nsulator鈥搈etal capacitors, with Cp-based precursors Sr(iPr₃Cp)₂ and Cp*Ti(OMe)₃ [Cp* = C₅(CH₃)₅] employed as the Sr and Ti precursors, respectively. While the Sr precursor has a higher reactivity toward oxygen on the Ru substrate compared with another Ti precursor, with a 2,2,6,6-tetramethyl-3,5-heptanedionato ligand, which results in the highly Sr excessive STO film, the enhanced reactivity of the present Ti precursor suppressed the unwanted excessive incorporation of Sr into the film. A possible mechanism for the Sr overgrowth and retardation is suggested in detail. By controlling the subcycle ratio of SrO and TiO₂ layers, stoichiometric STO could be obtained, even without employing a deleterious reaction barrier layer. This improved the attainable minimum equivalent oxide thickness of the Pt/STO/RuO₂ capacitor to 0.43 nm, with acceptable leakage current density (8 脳 10^鈥? A/cm²). This indicates an improvement of 25% in the capacitance density compared with previous work.

Keywords:

SrTiO₃; atomic layer deposition; DRAM; capacitor; Ru; RuO₂