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

详细信息    查看全文

• 作者：Gulaim A. Seisenbaeva ; Suresh Gohil ; Vadim G. Kessler ; Michel Andrieux ; Corinne Legros ; Patrick Ribot ; M. Brunet ; E. Scheid
• 关键词：Strontium titanate (STO) ; Volatility studies ; Gas phase behaviour ; Solution stability ; Deposition optimization
• 刊名：Applied Surface Science
• 出版年：2011
• 出版时间：1 January 2011
• 年：2011
• 卷：257
• 期：6
• 页码：2281-2290
• 全文大小：1598 K

文摘

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, ⁿPr, are stable and volatile, but possess a wrong composition. Highly volatile precursor Sr₂Ti₂(thd)₄(OⁱBu)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 (1 0 0) Si.