Semiconductor device and manufacturing method thereof

摘要

A first oxide insulating film is formed over a substrate. After a first oxide semiconductor film is formed over the first oxide insulating film, heat treatment is performed, so that hydrogen contained in the first oxide semiconductor film is released and part of oxygen contained in the first oxide insulating film is diffused into the first oxide semiconductor film. Thus, a second oxide semiconductor film with reduced hydrogen concentration and reduced oxygen defect is formed. Then, the second oxide semiconductor film is selectively etched to form a third oxide semiconductor film, and a second oxide insulating film is formed. The second oxide insulating film is selectively etched and a protective film covering an end portion of the third oxide semiconductor film is formed. Then, a pair of electrodes, a gate insulating film, and a gate electrode are formed over the third oxide semiconductor film and the protective film.

主权项

1. A method for manufacturing a semiconductor device, comprising steps of:
forming a first oxide insulating film over a substrate; forming an oxide semiconductor film over the first oxide insulating film; performing heat treatment to the oxide semiconductor film; selectively etching the oxide semiconductor film to have an end portion of the oxide semiconductor film, wherein the end portion of the oxide semiconductor film comprises a side surface and a top surface of the oxide semiconductor film; forming a second oxide insulating film over the oxide semiconductor film; selectively etching the second oxide insulating film, thereby forming a protective film covering the end portion of the oxide semiconductor film; forming a pair of wirings in direct contact with the protective film and the oxide semiconductor film; forming a gate insulating film in direct contact with the top surface of the oxide semiconductor film after forming the protective film; and forming a gate electrode overlapping with the oxide semiconductor film over the gate insulating film.