Synthesis of barium titanate films on TiN/Si substratesby atmospheric pressure plasma jet

• Main Authors: I-Tien Sun, 孫毅天
• Other Authors: 呂福興
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/85827251477791385932

碩士 === 國立中興大學 === 材料科學與工程學系所 === 102 === The aim of this work is to synthesize cubic barium titanate films on TiN-coated Si substrate by atmospheric pressure plasma jet (APPJ) using 0.025 M - 0.3 M Ba(NO3)2 with 0.05 M and 0.1 M Ti(NO3)4 as precursors. TiN films, acted as the buffer layer to make a single-phased BaTiO3. After the APPJ treatment, the as-deposited films were annealed in vacuum and air at 700C for 1 hr. The chemical structure and growth mechanism of those films made by various precursor concentrations was also explored. For comparison, synthesizing BaTiO3 on Si substrates were also investigated. Using 0.025 M Ba(NO3)2 and 0.05 M Ti(NO3)4 as precursors, cubic BaTiO3 films were directly prepared without further annealing. Mixed phases of BaTiO3, Ba(NO3)2 and BaO were formed by using other precursor concentrations. After annealing, cubic BaTiO3 or BaTiO3/Ba2TiO4 mixed phases were obtained on TiN/Si substrates in vacuum. The composition and structure of those films were different by varying Ba2+ concentrations. In addition, BaTiO3 reacted with Si to form Ba2TiSi2O8 after annealing in either vacuum or air when Si was used as the substrates. TiN films played as the buffer layer to inhibit the formation of Ba2TiSi2O8. Compared to those annealed in air,the oxidation of TiN films and the formation of Ba2TiSi2O8 were suppressed after annealing in vacuum. The dielectric constant of cubic BaTiO3 films was 621 at 10 kHz and 138 at 100 kHz; the dielectric loss was 1.66 at 10 kHz and 0.87 at 100 kHz after annealing in vacuum by using 0.05 M Ba(NO3)2 and 0.1 M Ti(NO3)4 as precursor. The dielectric constant and dielectric loss were higher than those reported in the literature. The growth mechanisms of BaTiO3 films by APPJ were discussed by varying the reaction time. Cubic BaTiO3 particles were formed in the beginning. Increasing the reaction time yielded the formation of Ba(NO3)2 and BaO particles. After annealing at 700C for 1 hr, only cubic BaTiO3 particles were produced. In addition, Ba2TiO4 were formed when Ba2+ ions concentrations were higher than 0.075 M.