The Fabrication And Performance Studies Of Ba-Al-B-Si/Ba_0.3Sr_0.7TiO₃Laminated Composite Dielectric Films

In the tendency of "lighter, thinner, smaller", how to improve the breakdownstrength and energy storage density is very important in the field of energy storagefilm studies. In the tradition of BST thin film dielectric materials, due to the influenceof the intrinsic features of BST ceramic materials, the breakdown strength and theenergy storage density of dielectric films still need to be improved. In order to solvethis problem, additional Ba-Al-B-Si glass film on Ba0.3Sr0.7TiO3(BST) thin film wasgrown to improve the breakdown strength and the energy storage density of BST thinfilms by sol-gel method. It was expected that this method could combine theadvantages of BST ceramics and the high breakdown characteristics of Ba-Al-B-Siglass, improving the performance of energy storage, and provide a new research ideaand solution for the study of composition of ceramic and glass. The synthesisprocedure of Ba-Al-B-Si glass film, Ba0.3Sr0.7TiO3film andBa-Al-B-Si/Ba0.3Sr0.7TiO3laminated composite dielectric films by sol-gel method. Inaddition, the influence of preparation conditions of sol-gel method and spin-coatingmethod, the thickness of the glass film on the microstructure and phase structure,dielectric performance, the breakdown performance and storage performance on theBa-Al-B-Si/Ba0.3Sr0.7TiO3laminated composite dielectric films were also studied,details contents are as follows:(1) Studying the influence of the mole ratio of water and TEOS, pH value andthe amount of organic additives for the synthesis of Ba-Al-B-Si glass film by sol-gelmethod and finally the amorphous glass film was successfully obtained;(2Studying the influence of pH value, the amount of the content of acetylacetone and DMF for the synthesis of Ba0.3Sr0.7TiO3film;(3) Ba-Al-B-Si/Ba0.3Sr0.7TiO3laminated dielectric films were synthesizedsuccessfully by the spin coating method, adjusting the spin coating processparameters and applicated different annealing processes on the BST layers andBa-Al-B-Si layers;High breakdown strength of glass was obtained by adding the Ba-Al-B-Si glass laminated layer on the surface of Ba0.3Sr0.7TiO3thin film. The breakdown propertiesof Ba-Al-B-Si/Ba0.3Sr0.7TiO3laminated composite dielectric films perform better thanthe pure Ba0.3Sr0.7TiO3film. At room temperature, under the frequency of1kHz, thebreakdown strength of Ba0.3Sr0.7TiO3thin film is145.7kV/mm, while the breakdownstrength of Ba-Al-B-Si/Ba0.3Sr0.7TiO3laminated composite dielectric films is199.8kV/mm, the breakdown strength has increased by37%; Due to the highbreakdown strength, the performance of energy storage of the laminated dielectricfilms has improved greatly. When applied voltage (D.C)=20v, the energy storagedensity of Ba0.3Sr0.7TiO3film is1.75J/cm3,while the energy storage density ofBa-Al-B-Si/Ba0.3Sr0.7TiO3laminated composite dielectric films reach3.25J/cm3improving by86%.According the study results, it can be concluded that addingBa-Al-B-Si glass laminated layer on the surface of Ba0.3Sr0.7TiO3thin film couldlargely improve the breakdown properties of BST film. The improvement of energystorage properties is remarkable.