RESUMEN
The incorporation of a thin, atomic layer deposited Al2O3 layer in between a spin-coated poly-4-vinyl phenol (PVP) organic layer and octadecyltrichlorsilane (OTS) in the multilayer gate dielectric for pentacene organic thin film transistors on a n(+)-Si substrate reduced the gate leakage current and thereby significantly enhanced the current on/off ratio up to 2.8 x 10(6). Addition of the OTS monolayer on the UV-treated Al2O3 improved the crystallinity of the pentacene layer, where the OTS/UV-treated Al2O3 surfaces increased their contact angles to 100 degrees. X-ray diffraction (XRD) analysis revealed a more intense (001) crystal reflectance of pentacene deposited on OTS/UV-treated Al2O3 surface than that on OTS/Al2O3 surface. Moreover, the improved pentacene layer contributed to the field effect mobility (0.4 cm2/Vs) and subsequently improved the electrical performances of organic thin film transistor (OTFT) devices. This PVP/UV treated Al2O3/OTS multilayer gate dielectric stack was superior to those of the device with the single PVP gate dielectrics due to the improved crystallinity of pentacene.
RESUMEN
We have investigated a novel method for patterning of (3, 4-ethylenedioxythiophene) PEDOT, which has involved a selective polymerization of PEDOT on an UV-activated Self-Assembled-Monolayer surface. OTS coated surface has been activated by UV exposure, and the UV-exposed area served as adsorption sites for FeCl3 oxidants, providing a selective deposition of PEDOT films on FeCl3 adsorbed area, and thus leading to the selective patterning of PEDOT films. UV irradiation time and mask pattern dimension are main contributors to patternability: UV irradiation through Cr-mask (3 microm design) lead to approximately 3-5 microm patterns of PEDOT films, depending on the UV exposure time. In addition, a scotch tape peel test revealed excellent adhesion property of PEDOT to SiO2. Consequently, this simple method can be applied to define deep submicron dimensions due to its ability of providing a direct transfer of mask patterns to the substrate.
