Preparation and Characterization of Dielectric BaTiO3 films by Sputter Deposition

• Main Authors: Shen Che Lee, 李昇哲
• Other Authors: J.P. Chu
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/08499306373103833658

碩士 === 國立海洋大學 === 材料工程研究所 === 88 === Film deposition, crystography and thermal analyses as well as electrical properties of R.F. sputtered BaTiO3 with various niobium concentrations on glasses and silicon wafer substrates have been studied. Characterizations of film including composition, activation energies, crystallization, microstructure and electrical properties are preformed as functions of components, Post-annealing temperatures and oxygen/Argon ratio. The deposition rate increases with oxygen introduced during deposition, reaching a maximum at 25% of O2/Ar followed by a decrease with oxygen. Increases in amount of niobium and annealing temperatures would improve the film crystallinity. The activation energy from an amorphous state to crystallization of free standing BaTiO3 thin film is measured to be 139.2KJ/mole. Crystallization peak temperature of BaTiO3 film is found to be 467.6°C at a heating rate of 20 °C/min and it tends to increase with addition of Nb. The films are amorphous after annealing at or below 420oC and become crystallized at annealing temperatures at or above 550oC. The morphology of film is of a typical columnar structure. The dielectric constant increases with increases with the amount of Nb, annealing temperature or oxygen concentration during deposition. The maximum dielectric constant is 749. With the decreased frequency or increased annealing temperature, the dielectric constant increases. The I-V measurement shows that the leakage current density of film increase with the annealing temperature increases.