Enhancement of breakdown strength of SrTiO3/nano-SiO2 composite film prepared by sol-gel technology

Dielectric (1-x)SrTiO3/xSiO2 (x=0, 0.01, 0.05 and 0.1) composite thin films were deposited onto Pt (100)/Ti/SiO2/Si substrates via sol-gel and spin coating technology and their surface morphology was examined by field emission scanning electron microscopy, indicating that surface morphology was apparently influenced by the nano-SiO2 addition. A broad adsorption band at 3200-3500 cm−1 attributed to stretching vibrations of O-H bonds in the absorbed water was observed in fourier transform infrared spectroscopy (FTIR). The X-ray photoelectron spectroscopy (XPS) results show that nano-SiO2 particles facilitate water absorption of STO thin films. The breakdown strength of SrTiO3/nano-SiO2 composite films is increased to about 332 MV/m. At the same time, the leakage current of 0.9SrTiO3/0.1SiO2 composite thin films decreases by two orders of magnitude under high electric field. Above results show that nano-SiO2 particles facilitate water absorption of the thin films, making SrTiO3 act as an effective solid state electrolyte for the anodic oxidation to achieve higher breakdown strength.