| abstract |
This invention provides an amorphous oxide semiconductor thin film, which is insoluble in a phosphoric acid-based etching solution and is soluble in an oxalic acid-based etching solution by optimizing the amounts of indium, tin, and zinc, a method of producing the amorphous oxide semiconductor thin film, etc. An image display device ( 1 ) comprises a glass substrate ( 10 ), a liquid crystal ( 40 ) as a light control element, a bottom gate-type thin film transistor ( 1 ) for driving the liquid crystal ( 40 ), a pixel electrode ( 30 ), and an opposing electrode ( 50 ). The amorphous oxide semiconductor thin film ( 2 ) in the bottom gate-type thin film transistor ( 1 ) has a carrier density of less than 10 +18 cm −3 , is insoluble in a phosphoric acid-based etching liquid, and is soluble in an oxalic acid-based etching liquid. |