AVS 52nd International Symposium
    Electronic Materials and Processing Tuesday Sessions
       Session EM-TuP

Paper EM-TuP7
Poly(3-hexylthiophene) Organic Thin Film Transistor on Polyimide using Electroplated Au Electrodes

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Electronic Materials and Processing Poster Session
Presenter: J.G. Lee, Sungkyunkwan University, South Korea
Authors: J.G. Lee, Sungkyunkwan University, South Korea
Y.G. Seol, Sungkyunkwan University, South Korea
N.-E. Lee, Sungkyunkwan University, South Korea
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Organic thin film transistors (OTFT) on flexible substrate utilizing electroplated Au electrodes have potential advantages in the fabrication of flexible devices requiring large area coverage, structural flexibility, low-temperature processing, and especially low cost. In particular, the application of electroplated electrode with the adhesion layer enables one to obtain reliable devices on the flexible substrate in terms of mechanical flexibility and thermal stability, as proved in the flexible printed circuit board (FPCB) technology. In this work, poly(3-hexylthiophene) (P3HT) OTFT devices with a top-gate structure were fabricated by utilizing the electroplated Au source and drain electrodes on polyimide substrate. First, since the adhesion of electrodes on the flexible substrate is of great importance for the application in flexible devices, the adhesion improvement of electroplated electrode structures was achieved by plasma treatment of polyimide substrate followed by a sequential sputter-deposition of Cr(adhesion) and metal seed layers. Au source/drain electrodes were electroplated into the patterned SU-8 mask by ultra-violet photolithography. After SU-8 ashing and Cr/Cu layer removal, spin-coating of P3HT layers, and gate dielectric formation, and Al electrode deposition were carried out. Here, organic-inorganic hybrid gate dielectric layers as well as organic PVP gate dielectric were employed. The channel length ranged between 5 and 110 µm, and the channel width was 800 µm. Electrical properties of fabricated OTFTs were characterized and the effect of various process conditions and structures on the performances of the fabricated devices will be discussed.