Study on dielectric property of BST of gradient thick films

摘要

The multilayer BST thick film with composition gradient is becoming the important alternative material for the infrared detector and microwave modulator due to its good comprehensive dielectric properties such as moderate dielectric constant and high dielectric-temperature coefficient, etc. The Mn-doped BST thick film with six different layers of composition gradients is fabricated in the Pt/Ti/SiO_2/Si silicon chip by improved sol-gel method. The thick film is about 5μm thick. Then the micro structure and dielectric property of the gradient thick film is studied. The XRD analysis shows that the thick film with complete perovskite structure can be obtained when the heat treatment temperature reaches 750°C. The SEM microscope demonstrates that the surface grains have uniform size with dense arrangement and good density, and the dielectric peak temperature zone of the gradient BST thick film covers the normal temperature with dielectric coefficient 920 and dielectric loss approximately 1.8×10~(-2).