Thin film transistor having an oxide semiconductor and metal oxide films

摘要

The oxide semiconductor film has the top and bottom surface portions each provided with a metal oxide film containing a constituent similar to that of the oxide semiconductor film. An insulating film containing a different constituent from the metal oxide film and the oxide semiconductor film is further formed in contact with a surface of the metal oxide film, which is opposite to the surface in contact with the oxide semiconductor film. The oxide semiconductor film used for the active layer of the transistor is an oxide semiconductor film highly purified to be electrically i-type (intrinsic) by removing impurities such as hydrogen, moisture, a hydroxyl group, and hydride from the oxide semiconductor and supplying oxygen which is a major constituent of the oxide semiconductor and is simultaneously reduced in a step of removing impurities.

主权项

1. A semiconductor device comprising:
a gate electrode; a gate insulating film covering the gate electrode; a first metal oxide film over and in contact with the gate insulating film; an oxide semiconductor film over and in contact with the first metal oxide film and overlapping with the gate electrode; source and drain electrodes over and in electrical contact with the oxide semiconductor film; a second metal oxide film over and in contact with the oxide semiconductor film; and an insulating film over the second metal oxide film, wherein each of the first metal oxide film and the second metal oxide film comprises one or more constituent metal elements of the oxide semiconductor film, and wherein the first metal oxide film is in contact with the second metal oxide film.