Title: Deposition of transparent electrodes for the future generation of flexible displays

Authors: Mariya P. Aleksandrova; Georgy H. Dobrikov; Kostadinka A. Gesheva; Georgy K. Bodurov; Ivelina N. Cholakova; Geogy D. Kolev

Addresses: Department of Microelectronics, Faculty of Electronic Engineering and Technologies, Technical University of Sofia, Sofia, 1000, 'Kliment Ohridski' Blvd., No. 8, bl.1, Bulgaria ' Department of Microelectronics, Faculty of Electronic Engineering and Technologies, Technical University of Sofia, Sofia, 1000, 'Kliment Ohridski' Blvd., No. 8, bl.1, Bulgaria ' Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, Sofia, 1784, 'Tzarigradsko Chaussee' Blvd., No. 72, Bulgaria ' Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, Sofia, 1784, 'Tzarigradsko Chaussee' Blvd., No. 72, Bulgaria ' Department of Microelectronics, Faculty of Electronic Engineering and Technologies, Technical University of Sofia, Sofia, 1000, 'Kliment Ohridski' Blvd., No. 8, bl.1, Bulgaria ' Department of Microelectronics, Faculty of Electronic Engineering and Technologies, Technical University of Sofia, Sofia, 1000, 'Kliment Ohridski' Blvd., No. 8, bl.1, Bulgaria

Abstract: Indium-tin oxide transparent films were deposited by modified method for radiofrequency (RF) vacuum sputtering on flexible substrate for application as display electrode. Amorphous, colourless and highly flexible polyethyleneterephtalate (PET) foil, having melting point of 80°C, was chosen as a flexible substrate. Modification consists of stage change of the plasma power from 75 W to 105 W, corresponding to deposition temperatures of 62°C and 75°C. It was found that the velocity of power change and the oxygen partial pressure variation with one order of magnitude (1.10R−3−2.10R−4 Torr), affects the film's resistance and transparency in a way suitable for application as a front panel display electrode. Coating transmittance of 83% in the visible spectrum range and specific resistance of 0.21 Ω.cm were achieved after plasma power changing. Coating's adhesive strength of 14 and 70 N/cm2 were measured for rates of sputtering power change 0.5 W/s and 3 W/s, respectively. Another important parameter is the post deposition exposure with UV light. Minimum specific resistance value of 0.4 Ω.cm and transparency of 89% were measured after UV post-deposition treatment.

Keywords: flexible displays; indium-tin oxide films; RF sputtering; transparent electrodes; radiofrequency sputtering; post-deposition treatment; UV light; ultraviolet; plasma power; coating transmittance.

DOI: 10.1504/IJRIS.2013.058769

International Journal of Reasoning-based Intelligent Systems, 2013 Vol.5 No.4, pp.246 - 252

Available online: 18 Jan 2014 *

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