Thermochemical Stability of IrO2 Bottom Electrodes in Direct-Liquid-Injection Metalorganic Chemical Vapor Deposition of Pb(Zr,Ti)O3 Films

Autor:	Won-Jong Lee, Kyung-Mun Byun
Rok vydání:	2004
Předmět:	Materials science Hydrogen General Engineering General Physics and Astronomy chemistry.chemical_element Chemical vapor deposition Ferroelectricity Oxygen Solvent chemistry Chemical engineering Electrode Metalorganic vapour phase epitaxy Thin film
Zdroj:	Japanese Journal of Applied Physics. 43:2655
ISSN:	1347-4065 0021-4922
DOI:	10.1143/jjap.43.2655
Popis:	The IrO2 film has been regarded as a leading candidate bottom electrode of ferroelectric capacitors in ferroelectric random access memories (FRAMs). We have addressed a new issue on the thermochemical stability of IrO2 bottom electrodes during the growth of Pb(Zr,Ti)O3 (PZT) ferroelectric films on such electrode using direct liquid injection metalorganic chemical vapor deposition (DLI-MOCVD). The IrO2 electrode thermally dissociated at elevated temperatures in vacuum ambient at a low oxygen pressure. It was also reduced by carbon and hydrogen dissociated from the solvent in liquid solution. The reduction of IrO2 by the solvent was more pronounced at lower temperatures, which is attributed to the longer residence time of solvent molecules on the IrO2 surface at lower temperatures. The reduction of IrO2 was also induced by the metal elements Zr and Ti in metalorganic precursors because they have higher chemical affinities with oxygen than Ir. The reduction by Zr and Ti metal elements was more pronounced at higher temperatures. The use of thin Pt interlayers is a promising solution for the prevention of the reduction of IrO2 electrode during the growth of PZT films.
Databáze:	OpenAIRE
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