In trying to downsize monolithic ceramic capacitors, we face the challenge of making the thinnest possible dielectric layer. To meet this challenge, we must create well-crystallized ceramic materials. One of the approaches is the micro-emulsion method. When we disperse water with an adequate surfactant into a hydrophobic solvent, ultra fine water particles at the nanometer level become emulsified. For example, if we add titanium and barium based compound alkoxide solution to react with water particles, we end up with crystallized barium titanate dispersion droplets approximately 8 nm in diameter. Because the synthesized particles are ultra-fine and well-dispersed, the dispersion droplets appear transparent. By directly forming a membrane with these dispersion droplets, we can make fine-grain, very thin membrane with superior dielectric property.

Conventionally, barium titanate particles lose their ferroelectricity when the grain size is reduced to approximately 50 nm. However, thin films formed with transparent dispersion droplets through the micro-emulsion method retain strong dielectric property at 20 nm.