P-23: Thin Durable Metal Substrates for High-Resolution a-Si TFT Active Matrix Displays

Abstract

We have developed thin, durable and flexible, metal substrates for a‐Si TFT active matrix displays. Fine‐patterned a‐Si TFTs can be fabricated using an Fe‐Ni 42 alloy metal foil with a low coefficient of thermal expansion as the flexible substrate. The metal foil is coated using a heat‐resistant polymer passivation layer, so that a conventional a‐Si TFT process, where the maximum substrate temperature is 300 °C, can be applied. A 0.29mm‐thick 200ppi 4″ VGA reflective LCD panel was realized using a 0.16mm thick metal substrate.

Technical issues of stainless steel foil substrates for OLED display applications

“…However, as shown in figure 1(b), only 20-30% improvement of surface roughness can be achieved from EP method. Therefore, additional planarization layer is unavoidable and single organic layer planarization technique without any polishing method has been studied by several research groups 16,17,18 . With single organic layer planarization technique, the cost of SS foils substrate preparation is expected to be competitive with that of plastic substrates with moisture and oxygen barrier coating or thin flexible glass substrates.…”

Fabrication of Flexible TFTs on a Heat-Resistant Transparent Polymer using the Standard a-Si TFT Process above 300ºC

“…Much research has focused on developing displays using flexible substrates, such as metal foils [1][2][3][4] or plastics [5][6][7][8][9][10][11]. Since the heat resistance of the plastic substrates is poor, they require lower process temperatures to make thin film transistors (TFTs) directly on them [5,6].…”

Reliability of Low Temperature Polycrystalline Silicon Thin-Film Transistors with Ultrathin Gate Oxide

“…In addition, TFT can be easily fabricated on large-area inexpensive substrates such as glass or plastic because it can be fabricated at 600 C or lower. 1,2) Owing to this technology, displays that incorporate part of the power supply and image processing circuits have been fabricated and incorporated into digital cameras, cellular phones and laptop (notebook-type) computers, for example. Recently, displays that include devices such as memories and photosensors have been reported.…”