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Research article - Peer-reviewed, 2011

Controlling precursor stability and evaporation through molecular design. Pseudo single source precursor approach to MOCVD SrTiO3 thin films

Seisenbaeva, Gulaim A.; Gohil, Suresh; Kessler, Vadim G.; Andrieux, Michel; Legros, Corinne; Ribot, Patrick; Brunet, M.; Scheid, E.


Strontium titanate SrTiO3 thin films have attracted interest as a possible gate dielectric material. Preparation of its high quality coatings is hindered by difference in volatility of the homometallic precursors - strontium beta-diketonates and titanium alkoxides. The only earlier known single-source precursor, a sec-alkoxide derivative Sr2Ti2(thd)(4)(OiPr)(8), has limited volatility. Bimetallic primary alkyl chain complexes, Sr4Ti2O(thd)(4)(OR)(10)(ROH)(2), R = Et, Pr-n, are stable and volatile, but possess a wrong composition. Highly volatile precursor Sr2Ti2(thd)(4)((OBu)-Bu-i)(8) has been prepared using an iso-alkoxide, combining proper ligand size with the sterical requirements, and characterized by multivariate evaporation analysis. Its evaporation is associated with complete decomposition into homometallic species, which, however, are evaporated in a single step. This permits to successfully use this novel precursor for SrTiO3 thin film deposition by DLI-MOCVD technique in a sufficiently broad established temperature range. Using optimized experimental conditions, 100 nm thick strontium titanate films with high permittivity have been successfully obtained on (100) Si. (C) 2010 Elsevier B.V. All rights reserved.


Strontium titanate (STO); Volatility studies; Gas phase behaviour; Solution stability; Deposition optimization

Published in

Applied Surface Science
2011, Volume: 257, number: 6, pages: 2281-2290
Publisher: Elsevier