| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 96 === Organic thin film transistors (OTFTs) have made impressive progress over the past decades, and it is now likely that OTFTs will find their applications in a number of ways. OTFTs basically provide two principal advantages over Si-based TFTs in processes and application: low thermal budget and low cost. One important factor for low temperature process may be how to fabricate a gate dielectric film at a low temperature. This is a difficult challenge.
We report on the fabrication of pentacene thin-film transistors (TFTs) with SiO2 films as the gate dielectric that has been deposited on a heavily doped Si-wafer by Hollow Cathode CVD at low temperature. Although the SiO2 was expected to show lower insulating properties than HDP-CVD SiO2, the surface properties exhibited smooth and a hydrophobic character. Therefore, the pentacene grain size on Hollow Cathode CVD SiO2 is much larger than HDP-CVD SiO2. Based on these arguments, it may result in OTFT using low-temperature hollow cathode CVD SiO2 with higher field mobility and on current. Our work demonstrates that 80 ℃-deposited SiO2 is not only promising gate dielectric material for organic TFTs, but also providing good transistors characteristic.
We also investigated the influence of the influence of different measuring environment on the electrical characteristics of pentacene-based thin film transistors. Through surface morphology analysis by atomic force microscopy (AFM) and absorption analysis by infrared (IR) spectroscopy, it was found that the adsorption of H2O on the pentacene layer was the main reason for the degradation. Therefore, we have demonstrated the number of the moisture is a important factor on the electrical characteristics of pentacene-based thin film transistors.
|
|---|
