Date of Award

5-2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Materials Science and Engineering

Advisor

Lee, Burtrand I

Committee Member

Luo , Jian

Committee Member

Skaar , Eric C

Abstract

The increasing needs for further functionality, higher performance, and miniaturization of electronic devices have highly demanded down-size and volume-efficiency of electronic components such as multilayer ceramic capacitors (MLCCs). To meet this demand, the use of high dielectric constant material with nanometer size and spherical shape is considered as requirements. Embedded capacitors are an important emerging technology for meeting the performance and functionality requirements of next-generation electronic devices. One major obstacle for implementing this technology is the scarcity of dielectric materials with appropriate dielectric and mechanical properties was mainly discussed

Considering these backgrounds, this research is devoted to synthesis of high dielectric constant materials, barium titanate (BaTiO3) nano-powders and silver/barium titanate (Ag/BaTiO3) nano-composite powders for the applications of MLCCs and embedded capacitors. A noble synthesis method, ambient conditions sol (ACS) process, which was developed in our lab, has been further investigated to produce desirable BaTiO3 and Ag/BaTiO3 powders. ACS process was divided into two processes, depending on the synthesis medium, water-based ambient condition sol (WACS) process and solvent-based ambient condition sol (SACS) process. In WACS, water is used as a main medium, while in SACS, large amount of organic solvent in aqueous solution or totally organic solvent without water is used.

For the first part, nanocrystalline BaTiO3 particles were prepared by WACS process. The effects of different processing parameters such as the concentration of Ba2+ ions and base and reaction time on the properties of the powders were investigated. In this work, how the content of the OH- defects in BaTiO3 lattices affect the tetragonality in a powder and dielectric constant was mainly discussed

For the second part, nanocrystalline BaTiO3 particles were prepared by SACS process. The effects of the concentration of an organic solvent in a mixed solvent on the properties were investigated.

For the last part, Ag/BaTiO3 nanocomposites were directly synthesized via an ambient condition sol (ACS) process. The properties of the composite powders were studied in relation to temperature of heat-treatment and Ag concentration.

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