Ba0.6Sr0.4TiO3 Thin Films Deposited by Spray Coating for High Capacitance Density Capacitors

Metal‐insulator‐metal (MIM) capacitors with Ba0.6Sr0.4TiO3 (BST) thin films as insulating layers are fabricated using a novel, fast, and low‐cost method. On one hand, the process lies in the swift, continuous, and scalable synthesis of BST nanoparticles using the supercritical fluid technology and, on the other hand, the nonpyrolytic spray coating of thin films using colloidal nanocrystals as ink. The authors focus on the deposition process of thin and uniform layer. A dispersed colloidal suspension based on BST nanoparticles is deposited on a hot copper substrate. A 200 nm thick dielectric film is successfully obtained. Electrical characterizations of Cu/BST/Al MIM structure demonstrate a state‐of‐the‐art capacitance density almost reaching 1 µF cm−2 within an operating voltage range of ±1 V. Moreover, an annealing process of the dielectric layer and the final MIM capacitor at 90 °C during 15 h brings a significant decrease of the leakage current by three decades from mA cm−2 to µA cm−2.