Characterization of Al2O3-TiO2 composite oxide films as the gate insulator layers prepared by solution-based process

• Main Authors: Jin-cheng Chen, 陳錦誠
• Other Authors: Chien-yie Tsay
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/35943239841571154566

碩士 === 逢甲大學 === 材料科學所 === 96 === This study successfully prepared Al2O3-TiO2 thin films by sol-gel process. Al2O3-TiO2 thin films have been deposited via spin coating from aqueous solution and utilized as gate insulator in TFT. Precursor solutions were prepared by the same functional group (or moieties) of metal Alkoxides. The same functional group will undergo the same or similar chemical reactions regardless of the size of the molecule. Aluminum sec-Butoxide and Titanium(IV) n-butoxide dissolved in ethanol as a solvent and acetylacetone , AcA as a chelating agent under vigorous stirring for 30 min, followed by the drop wise addition of a deionized water for hydrolysis and HNO3 as a catalyst. All the syntheses were carried out at room temperature under vigorous stirring condition. Al2O3-TiO2 thin films were prepared by depositing from fresh precursor solution on bare glass or ITO. Al2O3-TiO2 thin films are atomically smooth, dense, and amorphous, while exhibiting excellent morphologica stability to 400℃~500℃. It is evident that the transmission coefficient was approximately 91％ for both the treated films in the visible region. Al2O3-TiO2 thin films have low leakage current by electrical measurements. A leakage current density of 1.635×10-9 A/cm2 at 5V and 5.097×10-8 A/cm2 at 1 MV/cm and current limited breakdown field up to 3.12 MV/cm. The dielectric constant increased by increasing TiO2 ratios after 500℃ annealing and annealing temperature increased. The dielectric constant (εr) of 2.99 to 36.72 measured at 100 kHz.