Dissertation Outline    AFM/SEM Images    Dielectric Mixing Modeling


Preparation and Characterization of BaTiO3 Dielectric Thin/Thick Films for MLCC applications

My Ph.D. thesis research project was supported by KEMET Electronics Corporation and Industry Graduate Research Traineeship Program (IGRT) in South Carolina. The entire work consists of the following three parts:


Part I: The Deposition Processes of About One Micron BaTiO3 Thick Films


The purpose of this work is to develop new deposition methods to prepare much thinner BT layer (<3 micron) for much higher volumic efficiency capacitors. Based on the powder processing, the powder spin coating process and electrophoretic deoposition process were investigated and evaluated to achieve one micron BT thin layers with accepable dielectric and electric properties. The particle surface charging and electrophoretic deposition mechanisms were investigated. The thickness control and microstructures of BT layers were evaluated in terms of the process parameters.

Positive results were obtained to prepare about 1~5 micron BT thick films for MLCC applications. This deposition process is also expected to have potential applications for electronic thick film devices such as piezoelectric, pyroelectric sensors, actuators and semiconductor thin film devices, as well as thermal, chemical and wear-resistant coatings by using the reliable submicron powders.

Part II: Synthesis and Evaluation of Inorganic BaTiO3 Sol/Binder for MLCC Applications

(Patent Pending, 1999)
A highly stable, aqueous BaTiO3 sol system was successfully developed to be used as binder, dispersant, and sintering aid to produce well-dispersed BaTiO3 suspension made from the submicron (~0.2 micron) BaTiO3 particles. The effect of this inorganic binder on the microstructure,sintering behavior, and dielectric, electric properties of BaTiO3 thin layer is being investigated. Due to its much less shrinkage/weight loss compared to organic binders, it is believed that this inorganic BaTiO3 binder will increase the binding among BT powder instead of organic binder and eliminate the problems associated with the organic binder removal, and improve the dielectric and electric properties of the capacitors. Due to the low temperature sintering behavior and phase formation of this inorganic binder (<900oC), it is possible to decrease the BT sinterng temperature and allow the use of much less expensive metal electrodes for MLCC application after the use of this inorganic BT binder.

Part III: Preparation and Evaluation of BaTiO3 Dielectric/ Metal Electrode Multilayer


Using the deposition method in Part I and the inorganic binder in Part II, BT dielectric/metal electrode multilayer prototype capacitors will be made. The capacitor properties such as capacitance,dissipation factor, breakdown voltage,insulation resistance and TCC, will be evaluated.

See publication List for related papers.

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