Studies on the Fabrication and Characteristics ofFlexible Pentacene Thin-Film Transistors

• Main Authors: Yu-Tien Tang, 唐有田
• Other Authors: Chin-Tsou Kuo
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/80561950106107087250

碩士 === 大同大學 === 化學工程學系(所) === 96 === The main aim of this thesis studies on the characteristics of flexible thin-film transistor (TFT) fabricated with pentacene as a semiconductor layer, poly(ethylene terephthalate) (PET) as a plastic substrate, polyamide (PA) and poly(methyl methacrylate) (PMMA) acted as polymeric gate dielectric. We have chosen 1-octadecanethiol (1-ODT) and octadecyltrichlorosilane (OTS) used as treated agent for gate electrode to change the surface morphology of gate electrode in order to improve the orientation of the pentacene deposited on the polymer dielectric and to improvement device characteristics. The capacitance is 1.88 nF/cm2 of PA, 1.94 nF/cm2 of PA/PMMA and 0.99 nF/cm2 of PA/PMMA dual layer through the measurement on the architecture of Metal-Insulator-Semiconductor device at a frequency of 100 kHz. Part I, we have chosen PA acted as a polymeric gate dielectric. The mobility and on/off current ratio of the pentacene TFT are 0.36 cm2/Vs and 8.05 × 102, respectively. Further, the mobility and on/off current ratio of TFT with gate electrode treated with 1-ODT are 1.04 cm2/Vs and 1.40 × 103, respectively. The mobility and on/off current ratio of TFT for capping the surface of gate electrode with OTS are 1.33 cm2/Vs and 2.04 × 105, respectively. Existence of a single crystal phase with more intensity in theXRD pattern can be obtained the better performance of device. Atom Force Microscope (AFM) images showed that the surface of pentacene was more flatness and larger grain size, which can reduce the grain boundaries and the trap states, to improve the mobility. Part II, we have chosen PA/PMMA dual layer acted as polymeric gate dielectric. The mobility and on/off current ratio are 0.56 cm2/Vs and, 1.25 × 106, respectively. It is found that the leakage current reduced significantly tobe 5 pA such that the on/off current ratio increased to about 106, which is three orders of magnitude larger than that of device with PA gate dielectric. However, the improvement on the characteristics of TFT with 1-ODT or OTS treated gate electrode is unobvious. Part III, we have chosen PMMA/PA dual layer acted as polymeric gate dielectric. The mobility and on/off current ratio are only 0.30 cm2/Vs and 5.63× 103, respectively, but the I-V curves of the device exhibit the ideal characteristics.