Fueled by the anticipation of a high demand across a large class of applications, the field of "flexible electronics" (electronic systems on flexible substrates) has become a major research pursuit in the past decade. The biggest demand is in electronic displays, accounting for over 48% of the overall market. While processor and memory elec­ tronics are based on conventional silicon transistors, the same "hightemperature" technology are incompatible with the substrates for displays and flexible electronics, which are typically limited in their temperature tolerance. These systems are enabled by thin-film transistors (TFT).

Though the operating speed of a TFT is only moderate compared to a single-crystal silicon transistor, the overriding advantage is its substrate-compatible low processing temperature, generally in the range of 150°C to 500°C. The evolution of low-temperature TFT technology will be discussed, leading to those based on metal-oxide (MO) semicon­ ductors - destined to be the materials most suitable for the nextgeneration of commercial displays and flexible elec­ tronics. The elevated-metal metal-oxide (EMMO) TFT architecture, based on zinc-oxide and its variants, has demon­ strated the ability to overcome the limitations of the two conventional "back-channel etched" and "etch-stop layer" TFT architectures. The adaptation of EMMO TFT technology from a maximum process temperature of 400°C to 300°C and the performance obtained on a flexible substrate will be described.