Chemical Vapor Deposition of Barium Strontium Titanate Films with Direct Liquid Injection of Single‐Mixture Solution

Abstract

Chemical vapor deposition of barium strontium titanate (BST) thin films with direct liquid injection of a single‐mixture solution of ‐Lewis base adduct (tmhd=2,2,6,6‐tetramethyl‐3,5‐heptanedionate), ‐Lewis base adduct, and (i‐OPr = iso‐propoxide) was studied. Thermal characteristics of Ba and Sr precursor adducts with tetraethylene glycol dimethyl ether(tetraglyme) and pentamethyldiethylene triamine (PMDT) were compared. Using differential scanning calorimetry. the coordination of PMDT with metal‐tmhd compound was found to be stronger than tetraglyme, and the thermal stability of (A = tetraglyme or PMDT) was higher than . The optimum window of the vaporizer temperature of PMDT adduct was wider than the tetraglyme adduct. Ba and Sr incorporation into (Ba, Sr) films was about the same for both adducts. Ti incorporation was increased up to the deposition temperature of 470°C and some humps and hazy deposition were detected below 470°C due to the lack of Ti incorporation. Step coverage of (Ba, Sr) films was about 0.8 at the of 480°C and 0.3 at 550°C. Leakage current and the equivalent oxide thickness at 1.0 V were about and 0.96 nm at the deposition temperature above 470°C. © 1999 The Electrochemical Society. All rights reserved.