Semiconductor device and method for manufacturing semiconductor device

摘要

Provided is a method for manufacturing a transistor by which the defective shape of a semiconductor device is prevented in the case where a source electrode layer and a drain electrode layer are formed on an oxide semiconductor film. A source electrode layer and a drain electrode layer are formed each having a cross-sectional shape with which disconnection of a gate insulating film is unlikely to occur even when the gate insulating film over the source electrode layer and the drain electrode layer has a small thickness. An oxide semiconductor film having a crystal structure over an insulating surface is formed; an electrode layer on the oxide semiconductor film is formed; and a thickness of an exposed portion of the oxide semiconductor film is reduced by exposing the oxide semiconductor film to dilute hydrofluoric acid with a concentration higher than 0.0001% and lower than or equal to 0.25%.

主权项

1. A method for manufacturing a semiconductor device, comprising the steps of:
forming an oxide semiconductor layer; forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer; and exposing a part of the oxide semiconductor layer to diluted hydrofluoric acid after the formation of the source electrode layer and the drain electrode layer, wherein a concentration of the diluted hydrofluoric acid is higher than 0.0001% and lower than or equal to 0.25%.