Lcd and organic el display

Abstract

A switching element of LCDs or organic EL displays which uses a thin film transistor device, includes: a drain electrode, a source electrode, a channel layer contacting the drain electrode and the source electrode, wherein the channel layer comprises indium-gallium-zinc oxide having a transparent, amorphous state of a composition equivalent to InGaO 3 (ZnO) m (wherein m is a natural number less than 6) in a crystallized state, and the channel layer has a semi-insulating property represented by an electron mobility of more than 1 cm 2 /(V·sec) and an electron carrier concentration is less than 10 18 /cm 3 , a gate electrode, and a gate insulating film positioned between the gate electrode and the channel layer.

What is claimed is: 
     
         1 . A Liquid Crystal Display (LCD) including:
 a substrate; and   switching elements formed on the substrate;   wherein the substrate is one of a glass substrate, a plastic substrate or a plastic film, and   wherein each of the switching elements comprises a thin film transistor comprising:
 a gate terminal formed over the substrate; 
 a gate insulating film formed on the gate terminal; 
 an amorphous oxide channel layer formed on the gate insulating film, the amorphous oxide channel layer including In, Ga, Zn and O; 
 a drain terminal formed on the amorphous oxide channel layer, the drain terminal partially overlapping with the gate terminal; and 
 a source terminal formed on the amorphous oxide channel layer and apart from the drain terminal, the source terminal partially overlapping with the gate terminal. 
   
     
     
         2 . The LCD according to  claim 1 , wherein the switching element is operable in a normally off type. 
     
     
         3 . The LCD according to  claim 1 , wherein the amorphous oxide channel layer is formed such that an electron mobility of the amorphous oxide channel layer increases with an electron carrier concentration of the amorphous oxide channel layer. 
     
     
         4 . The LCD according to  claim 1 , wherein each thin film transistor further comprises a top-gate structure. 
     
     
         5 . The LCD according to  claim 1 , wherein each thin film transistor further comprises a bottom-gate structure. 
     
     
         6 . The LCD according to  claim 1 , wherein each of the drain terminal and the source terminal comprises a first layer contacting the amorphous oxide channel layer and a second layer formed on the first layer, the second layer comprising metal. 
     
     
         7 . An organic Electroluminescence (EL) display including:
 a substrate; and   switching elements formed on the substrate;   wherein the substrate is one of a glass substrate, a plastic substrate or a plastic film, and   wherein each of the switching elements comprises a thin film transistor comprising:
 a gate terminal formed over the substrate; 
 a gate insulating film formed on the gate terminal; 
 an amorphous oxide channel layer formed on the gate insulating film, the amorphous oxide channel layer including In, Ga, Zn and O; 
 a drain terminal formed on the amorphous oxide channel layer, the drain terminal partially overlapping with the gate terminal; and 
 a source terminal formed on the amorphous oxide channel layer and apart from the drain terminal, the source terminal partially overlapping with the gate terminal. 
   
     
     
         8 . The organic EL display according to  claim 7 , wherein the switching element is operable in a normally off type. 
     
     
         9 . The organic EL display according to  claim 7 , wherein the amorphous oxide channel layer is formed such that an electron mobility of the amorphous oxide channel layer increases with an electron carrier concentration of the amorphous oxide channel layer. 
     
     
         10 . The organic EL display according to  claim 7 , wherein each thin film transistor further comprises a top-gate structure. 
     
     
         11 . The organic EL display according to  claim 7 , wherein the thin film transistor further comprises a bottom-gate structure. 
     
     
         12 . The organic EL display according to  claim 7 , wherein each of the drain terminal and the source terminal comprises a first layer contacting the amorphous oxide channel layer and a second layer formed on the first layer, the second layer comprises metal.