The studies of dielectric loss and mechanical stress of barium strontium titanate thin films by adding chromium Layer

• Main Authors: Huang,Chiung-Hui, 黃瓊慧
• Other Authors: Lin,Jin-Shyong
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/67727029516914924624

碩士 === 國立勤益科技大學 === 機械工程系 === 101 === The effects of the thickness of the Cr seeding layer of Ba0.5Sr0.5TiO3 (BST) thin films grown on Pt/TiN/SiO2/Si substrates on crystallographic structure, surface morphology, dielectric loss, leakage current, and mechanical stress were investigated. Adding a Cr seeding layer to the interface between BST/Pt structures has a strong influence on BST film properties including dielectric loss, leakage current, the temperature coefficient of capacitance (TCC), and mechanical properties, as well as films grain sizes. BST films with a 2 nm Cr seeding layer showed grains that were denser, smoother, and smaller in size than those in specimens with the Cr seeding layer thickness = 0, 1, and 3 nm. The dielectric loss, leakage current density, thermal stability (TCC), Young’s modulus, and residual stress of BST films with a 2 nm Cr seeding layer are improved by about 59%, 1 order of magnitude at +62.5 kV/cm (at +1 V), 35 %, 41 %, and 28 %, respectively, compared with BST films without a Cr seeding layer. The mechanical stress of BST films had a significant effect on both microstructure and dielectric properties. It was observed that the residual stress of the BST/Pt interface was effectively reduced by adding a Cr seeding layer. The correlations of material properties with dielectric loss, leakage current, thermal stability, and residual stress properties suggest that adding a 2 nm Cr seeding layer to BST films is the optimal choice for metal-insulator-metal (MIM) device applications.