Indium gallium zinc oxide

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Indium gallium zinc oxide (IGZO) is a semiconducting material, consisting of indium (In), gallium (Ga), zinc (Zn) and oxygen (O), and often abbreviated as "IGZO". IGZO thin-film transistor (TFT) is used in the TFT backplane of flat-panel displays (FPDs). IGZO-TFT was developed by Professor Hideo Hosono's group at Tokyo Institute of Technology and Japan Science and Technology Agency (JST) in 2003 (crystalline IGZO-TFT)[1][2] and in 2004 (amorphous IGZO-TFT).[3] IGZO-TFT has 20-50 times higher mobilities than that of amorphous silicon, which has been used for current liquid-crystal displays (LCDs) and electronic papers; therefore, IGZO-TFT can improve operation speed, resolution and size of flat-panel displays, and is also considered as one of the most promising thin-film transistors to drive organic light-emitting diode (OLED) displays.

IGZO-TFT and applications are patented by JST,[4] and have been licensed to Samsung Electronics[5] in 2011 and Sharp[6] in 2012.

Sharp started the world's first production of LCD panels Incorporating IGZO-TFT in 2012.[7] Sharp employs IGZO-TFT for smartphones, tablets, 32" LCD, etc, in which the aperture ratio of the LCD is improved by up to 20%, and power consumption is improved by LCD idling stop technology owing to the high mobility and low off current of IGZO-TFT.[8] Sharp started to release high pixel-density panels for notebook applications.[9] IGZO-TFT is also employed in 14" 3,200x1,800 LCD of an ultrabook PC supplied from Fujitsu[10] and 55" OLED TV supplied from LG Electronics.[11]

Its advantage over zinc oxide is that it can be deposited as a uniform amorphous phase while retaining the high carrier mobility common to oxide semiconductors.[12] The transistors are slightly photo-sensitive, but the effect becomes significant only in the deep violet to ultra-violet (photon energy above 3 eV), offering the possibility of a fully transparent transistor.

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