SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF
An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.
1 . (canceled)
2 . A method for manufacturing a semiconductor device, comprising:
forming a first conductive film that serves as a first gate electrode;
forming a first insulating film over the first conductive film;
forming an oxide semiconductor film over the first insulating film;
forming a source electrode and a drain electrode by patterning a second conductive film formed over the oxide semiconductor film, whereby a top surface of a first region of the oxide semiconductor film that is located between the source electrode and the drain electrode is etched to have a smaller thickness than a second region of the oxide semiconductor film that is below the source electrode or the drain electrode;
forming a second insulating film over the oxide semiconductor film, the source electrode, and the drain electrode; and
forming a transparent film over the second insulating film by a sputtering method,
wherein the transparent film comprises metal oxide.
3 . The method according to claim 2 ,
wherein the oxide semiconductor film includes indium, zinc, and a metal different from indium and zinc.
4 . The method according to claim 2 ,
wherein the transparent film is a conductive film.
5 . The method according to claim 2 , further comprising:
performing a heat treatment on the oxide semiconductor film.
6 . The method according to claim 2 ,
wherein the second insulating film is in contact with the oxide semiconductor film and the transparent film.
7 . The method according to claim 2 ,
wherein the transparent film includes indium.
8 . The method according to claim 2 ,
wherein the transparent film includes zinc.
9 . A method for manufacturing a semiconductor device, comprising:
forming a first conductive film that serves as a first gate electrode;
forming a first insulating film over the first conductive film;
forming an oxide semiconductor film over the first insulating film;
forming a source electrode and a drain electrode by patterning a second conductive film formed over the oxide semiconductor film, whereby a top surface of a first region of the oxide semiconductor film that is located between the source electrode and the drain electrode is etched to have a smaller thickness than a second region of the oxide semiconductor film that is below the source electrode or the drain electrode;
forming a second insulating film over the oxide semiconductor film, the source electrode, and the drain electrode; and
forming a transparent film over the second insulating film by a sputtering method,
wherein the transparent film comprises metal oxide, and
wherein the second insulating film is an oxide insulating film.
10 . The method according to claim 9 ,
wherein the oxide semiconductor film includes indium, zinc, and a metal different from indium and zinc.
11 . The method according to claim 9 ,
wherein the transparent film is a conductive film.
12 . The method according to claim 9 , further comprising:
performing a heat treatment on the oxide semiconductor film.
13 . The method according to claim 9 ,
wherein the second insulating film is in contact with the oxide semiconductor film and the transparent film.
14 . The method according to claim 9 ,
wherein the transparent film includes indium.
15 . The method according to claim 9 ,
wherein the transparent film includes zinc.