Room Temperature Growth of Indium‐Tin Oxide on Organic Flexible Polymer Substrates Using a New Reactive‐Sputter Deposition Technology

Abstract

The ability to grow good quality transparent conductive oxides (TCOs) such as indium‐tin oxide (ITO) at room temperature on flexible organic substrates is of increasing importance to industry. This is fuelled mainly by emerging technologies such as flexible flat panel displays (FFPDs) and organic light‐emitting diodes (OLEDs). Standard growth techniques often require elevated substrate temperatures, rendering them unsuitable for growth on heat‐sensitive polymers. In this paper, we have used a new sputtering technology to reactively sputter‐deposit good quality ITO on a flexible polymer substrate that was maintained at less than 50 °C. The system is inherently stable and does not require closed‐loop feedback mechanisms to control the oxygen flow, such as the ones often found in commercial magnetron systems dedicated to ITO deposition. The electrical resistivity of the ITO we obtained was 5 × 10−4 Ωcm, and the absorption coefficient was around 4 000 cm−1 in the visible range. We also investigate the fundamental issues involved in the oxidation reaction process.magnified image

Preparation of [100] oriented SrTiO3 thin films on flexible polymer sheets

“…Since the discovery of transparent, flexible, thin-film oxide transistors, 1) the field of flexible oxide devices has developed rapidly. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Many of these devices use a polymer film, such as polyethylene terephthalate, as a flexible substrate. 22) Because these polymers are not heat resistant, many researchers have tried to reduce the process temperatures needed to fabricate such devices, including the growth temperature of the oxide film.…”

Discriminate Crystallinities of Tin Doped Indium Oxide Films on Self-Assembled Monolayers Modified Glass Substrates

“…Tin doped indium oxide (ITO) is the most commonly used transparent conducting oxide (TCO) in many optical and optoelectronic devices, which include solar cell electrodes, resistive heaters, antireflective coatings, heat reflecting mirrors, electromagnetic shield coatings and antistatic coatings for instrumental panels, liquid crystal displays (or flat panel displays), organic light-emitting diodes (OLED), and photodetectors. − A good quality ITO film requires high electrical conductivity and high optical transmission, which can be achieved with highly crystalline ITO films. , Accordingly, several methods have been developed for the fabrication of ITO films, and a good quality material is obtained when the temperature of the substrate is raised to around 220 °C. ,− This temperature requirement is not suitable for many of the recent devices due to the heat sensitivity of substrates used in the fabrication. To avoid the use of high temperature, plasma sputtering techniques have been developed for the low-temperature deposition, enabling fabrication of ITO films on a variety of substrates. , However, low-temperature deposition yields amorphous material with high resistivity and hence with limited performance. To improve the crystallinity and electrical properties of ITO films, high-power plasma, which uses a mixture of argon and oxygen, is generally used .…”

“…To avoid the use of high temperature, plasma sputtering techniques have been developed for the low-temperature deposition, enabling fabrication of ITO films on a variety of substrates. 10,11 However, low-temperature deposition yields amorphous material with high resistivity and hence with limited performance. To improve the crystallinity and electrical properties of ITO films, high-power plasma, which uses a mixture of argon and oxygen, is generally used.…”

Self-assembled monolayers induced inter-conversion of crystal structure by vertical to lateral growth of aluminium doped zinc oxide thin films

“…8 To avoid such difficulties, plasma sputtering techniques have been developed for the low temperature deposition, enabling fabrication of TCO films on a variety of substrates. 9 However, low temperature deposition yields amorphous materials with high resistivity indicating no direct control on crystal growth by gas phase deposition methods, which severely affects their performances. 6,8 Recently, a self-assembled monolayer (SAM) technique has been applied to improve the quality of thin films at ambient conditions.…”