Neo-Pentoxide Precursor Synthesis, Solution Preparation, and Electronic Properties of (Ba,Sr)TiO3 Thin Films Derived from a Solution Route
Source: Journal of Sol-Gel Science and Technology, Volume 16, Number 1-2, October 1999 , pp. 47-55(9)
Abstract:We have recently isolated the neo-pentoxide (HOCH_2CMe_3, ONp) derivatives of Ba, Sr, and Ti as Ba_4(ONp)_8(HONp)_6(py)_2, Sr_5(O)(ONp)_8(Solv)_5 (Solv = solvent), and Ti_2(ONp)_8, respectively. The combination of these precursors were found to be readily soluble in a wide range of solvents and thus were excellent candidates for preparation of barium strontium titanate ((Ba,Sr)TiO_3 or BST) thin films using spin-cast deposition techniques. The highest quality BST films for this system were generated from ternary mixtures dissolved in either pyridine or pyridine/toluene. By in situ VT-GIXRD analysis it was determined that the perovskite phase of BST was readily formed at 650°C. The electronic properties of films crystallized at 700°C indicated that the thin films (300 nm) possessed a dielectric constant of 120 (tan = 0.03) with a tunability of 29% at ±10 V. 300 nm films (700°C) which had been generated from a standard BST solution modified with a novel tridentate ligand, had a higher dielectric constant of 180 and a tunability of 35% at ±10 V. The collective characteristics of these precursors offer an attractive alternative to the more complex, less stable sol-gel precursors currently in use.
Document Type: Regular Paper
Affiliations: 1: Sandia National Laboratories, Advanced Materials Laboratory, 1001 University Boulevard SE, Albuquerque, NM 87106, USA 2: Sandia National Laboratories MS 1405, P.O. Box 5800, Albuquerque, NM 87185, USA 3: Department of Chemistry, New Mexico Institute of Mining and Technology Socorro, NM 87801, USA
Publication date: October 1, 1999