Electrical and mechanical properties of indium‐tin‐oxide films deposited on polymer substrate using organic buffer layer

Abstract The electrical and mechanical properties in indium‐tin‐oxide films deposited on polymer substrate were examined. The materials of substrates were polyethersulfone (PES) which have gas barrier layer and anti‐glare coating for plastic‐based devices. The experiments were performed by rf‐magnetron sputtering using a special instrument and buffer layers. Therefore, we obtained a very flat polymer substrate deposited ITO film and investigated the effects of buffer layers, and the instrument. Moreover, the influences of an oxygen partial pressure and post‐deposition annealing in ITO films deposited on polymer substrates were clarified. X‐ray diffraction observation, measurement of electrical property, and optical microscope observation were performed for the investigation of micro‐structure and electro‐mechanical properties, and they indicated that as‐deposited ITO thin films are amorphous and become quasi‐crystalline after adjusting oxygen partial pressure and thermal annealing above 180 °C. As a result, we obtained 20–25 O/sq of ITO films with good transmittance (above 80 %) ofoxygen contents with under 0.2 % and vacuum annealing. Furthermore, using organic buffer layer, we obtained ITO films which have a rather high electrical resistance (40–45 O/sq) but have improved optical (more than 85 %) and mechanical characteristics compared to the counterparts. Consequently, a prototype reflective color plastic film LCD was fabricated using the PES polymer substrates to confirm whether the ITO films could be realized in accordance with our experimental results.

[1]  H. Hoffmann,et al.  Hf-sputtered indium oxide films doped with tin , 1978 .

[2]  T. W. Sigmon,et al.  Excimer laser crystallization and doping of silicon films on plastic substrates , 1997 .

[3]  W. F. Schmidt,et al.  Determination of Young's modulus of thin films used in embedded passive devices , 1997, 1997 Proceedings 47th Electronic Components and Technology Conference.

[4]  Characteristics of Low-Temperature-Processed a-Si TFT for Plastic Substrates , 2000 .

[5]  Gi-Seok Heo,et al.  TIZO/Ag/TIZO Multilayer Films for the Application of a Very Low Resistance Transparent Electrode , 1999 .

[6]  Li-Jian Meng,et al.  Properties of indium tin oxide films prepared by rf reactive magnetron sputtering at different substrate temperature , 1998 .

[7]  M. Buchanan,et al.  The influence of target oxidation and growth-related effects on the electrical properties of reactively sputtered films of tin-doped indium oxide , 1981 .

[8]  Martin Randler,et al.  49.1: A Bright Bistable FLC-Display on Plastic Substrates for Smart Cards , 2000 .

[9]  L. Schaper,et al.  Anodization for forming thin film embedded capacitors in MCM-D and MCM-L substrates , 1998, 1998 Proceedings. 48th Electronic Components and Technology Conference (Cat. No.98CH36206).

[10]  D. McCulloch,et al.  Novel fingerprint scanning arrays using polysilicon TFT's on glass and polymer substrates , 1997, IEEE Electron Device Letters.

[11]  S. K. Park,et al.  33.2: Development of 2‐in. Plastic‐Film STN‐LCD with Uniform Cell Gap , 2000 .

[12]  A. Kulkarni,et al.  Estimation and verification of the electrical properties of indium tin oxide based on the energy band diagram , 1996 .

[13]  John C. C. Fan,et al.  Effect of O2 pressure during deposition on properties of rf‐sputtered Sn‐doped In2O3 films , 1977 .

[14]  K. H. Schulz,et al.  Dependence of the sheet resistance of indium-tin-oxide thin films on grain size and grain orientation determined from X-ray diffraction techniques , 1999 .

[15]  Jeong In Han,et al.  Chip Bonding on Non-rigid and Flexible Substrates with New Stepped Processes , 2001 .

[16]  Kazuhiko Yokogawa,et al.  Postdeposition Annealing Influence on Sputtered Indium Tin Oxide Film Characteristics , 1994 .