SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

摘要

A highly reliable semiconductor device and a method for manufacturing the semiconductor device are provided. In a semiconductor device including a bottom-gate transistor in which an insulating layer functioning as a channel protective film is provided over an oxide semiconductor film, elements contained in an etching gas can be prevented from remaining as impurities on a surface of the oxide semiconductor film by performing impurity-removing process after formation of an insulating layer provided over and in contact with the oxide semiconductor film and/or formation of source and drain electrode layers. The impurity concentration in the surface of the oxide semiconductor film is lower than or equal to 5×1018 atoms/cm3, preferably lower than or equal to 1×1018 atoms/cm3.

主权项

1. A semiconductor device comprising:
a gate electrode layer; a gate insulating film over the gate electrode layer; an oxide semiconductor film over the gate insulating film; an insulating layer over the oxide semiconductor film, the insulating layer overlapping with the gate electrode layer; a source electrode layer over the oxide semiconductor film and the insulating layer; and a drain electrode layer over the oxide semiconductor film and the insulating layer, wherein a length of each of the source electrode layer and the drain electrode layer in a channel width direction is smaller than a length of the oxide semiconductor film in the channel width direction, and wherein a chlorine concentration in the oxide semiconductor film is lower than or equal to 5×1018 atoms/cm3.