Semiconductor device and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-2016013298-A1
Application number	US-201514856829-A
Country	US
Kind code	A1
Filing date	Sep 17, 2015
Priority date	Jan 26, 2012
Publication date	Jan 14, 2016
Grant date	—

Abstract

To provide a highly reliable semiconductor device by giving stable electrical characteristics to a transistor including an oxide semiconductor film. A gate electrode layer is formed over a substrate, a gate insulating film is formed over the gate electrode layer, an oxide semiconductor film is formed over the gate insulating film, a conductive film is formed over the oxide semiconductor film, so that a region in vicinity of an interface with the oxide semiconductor film in contact with the conductive film is made amorphous, heat treatment is performed, the conductive film is then processed to form a source electrode layer and a drain electrode layer, and a part of the amorphous region in the oxide semiconductor film which is exposed by formation of the source electrode layer and the drain electrode layer is removed.

First claim

1 . (canceled)

2 . A method for manufacturing a semiconductor device, comprising steps of:
forming a gate insulating film over a gate electrode; forming an oxide semiconductor film over the gate insulating film, the oxide semiconductor film comprising indium, gallium, and zinc; forming a conductive film over the oxide semiconductor film so that the oxide semiconductor film includes a first region in contact with the conductive film and a second region other than the first region, wherein crystallinity of the first region is lower than crystallinity of the second region; processing the conductive film to form a source electrode and a drain electrode so that the first region is exposed; removing a part of the first region which is exposed; and forming an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode after removing the part of the first region, wherein the insulating film is in contact with the oxide semiconductor film at least between the source electrode and the drain electrode, wherein an atomic percentage of gallium is greater than or equal to an atomic percentage of indium in the second region.

3 . The method according to claim 2 , wherein the first region is amorphous.

4 . The method according to claim 2 , wherein, in the oxide semiconductor film, a proportion of a crystal part to an amorphous part in the first region is lower than a proportion of a crystal part to an amorphous part in the second region.

5 . The method according to claim 2 ,
wherein the oxide semiconductor film includes a third region, a fourth region, and a fifth region, wherein the third region overlaps with the source electrode, wherein the fourth region overlaps with the drain electrode, wherein the fifth region overlaps with neither the source electrode nor the drain electrode, and wherein a thickness of the third region and a thickness of the fourth region are larger than a thickness of the fifth region.

6 . The method according to claim 5 ,
wherein the fifth region is positioned between the third region and the fourth region in a channel length direction, and wherein each of the third region and the fourth region is positioned between parts of the fifth region in a channel width direction.

7 . The method according to claim 2 , further comprising a step of:
performing heat treatment to the oxide semiconductor film.

8 . A method for manufacturing a semiconductor device, comprising steps of:
forming a gate insulating film over a gate electrode; forming an oxide semiconductor film over the gate insulating film, the oxide semiconductor film comprising indium, gallium, and zinc; introducing an element to a surface of the oxide semiconductor film so that the oxide semiconductor film includes a first region including the surface of the oxide semiconductor film and a second region other than the first region, wherein crystallinity of the first region is lower than crystallinity of the second region; forming a source electrode and a drain electrode so that the first region is exposed; removing a part of the first region which is exposed; and forming an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode after removing the part of the first region, wherein the insulating film is in contact with the oxide semiconductor film at least between the source electrode and the drain electrode, wherein an atomic percentage of gallium is greater than or equal to an atomic percentage of indium in the second region.

9 . The method according to claim 8 , wherein the element is at least one selected from the group consisting of elements of Group 15, elements of Group 13 in the periodic table, and rare gas elements.

10 . The method according to claim 8 , wherein the first region is amorphous.

11 . The method according to claim 8 , wherein, in the oxide semiconductor film, a proportion of a crystal part to an amorphous part in the first region is lower than a proportion of a crystal part to an amorphous part in the second region.

12 . The method according to claim 8 ,
wherein the oxide semiconductor film includes a third region, a fourth region, and a fifth region, wherein the third region overlaps with the source electrode, wherein the fourth region overlaps with the drain electrode, wherein the fifth region overlaps with neither the source electrode nor the drain electrode, and wherein a thickness of the third region and a thickness of the fourth region are larger than a thickness of the fifth region.

13 . The method according to claim 12 ,
wherein the fifth region is positioned between the third region and the fourth region in a channel length direction, and wherein each of the third region and the fourth region is positioned between parts of the fifth region in a channel width direction.

14 . The method according to claim 8 , further comprising a step of:
performing heat treatment to the oxide semiconductor film.

15 . A method for manufacturing a semiconductor device, comprising steps of:
forming a gate insulating film over a gate electrode; forming a first oxide semiconductor film over the gate insulating film, the first oxide semiconductor film comprising indium, gallium, and zinc; forming a second oxide semiconductor film over the gate insulating film, the second oxide semiconductor film comprising indium, gallium, and zinc, wherein crystallinity of the second oxide semiconductor film is lower than crystallinity of the first oxide semiconductor film; forming a conductive film over the second oxide semiconductor film; processing the conductive film to form a source electrode and a drain electrode so that the second oxide semiconductor film is exposed; removing a part of the second oxide semiconductor film which is exposed so that the first oxide semiconductor film is exposed; and forming an insulating film over the first oxide semiconductor film, the source electrode, and the drain electrode after removing the part of the second oxide semiconductor film, wherein the insulating film is in contact with the first oxide semiconductor film at least between the source electrode and the drain electrode, wherein an atomic percentage of indium is greater than or equal to an atomic percentage of gallium in the first oxide semiconductor film, and wherein an atomic percentage of gallium is greater than or equal to an atomic percentage of indium in the second oxide semiconductor film.

16 . The method according to claim 15 , wherein the second oxide semiconductor film includes an amorphous part.

17 . The method according to claim 15 ,
wherein the first oxide semiconductor film includes a third region, a fourth region, and a fifth region, wherein the third region overlaps with the source electrode, wherein the fourth region overlaps with the drain electrode, wherein the fifth region overlaps with neither the source electrode nor the drain electrode, and wherein the second oxide semiconductor film covers the third region and the fourth region, and wherein the second oxide semiconductor film does not cover the fifth region.

18 . The method according to claim 17 ,
wherein the fifth region is positioned between the third region and the fourth region in a channel length direction, and wherein each of the third region and the fourth region is positioned between parts of the fifth region in a channel width direction.

19 . The method according to claim 15 , further comprising a step of:
performing heat treatment to

Assignees

• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei

Classifications

• H10P95/90

  Thermal treatments, e.g. annealing or sintering · CPC title

• H10P95/00

  Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass · CPC title

• H10P14/3434

  being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424) · CPC title

• H10D30/6757

  characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715) · CPC title

• H10D99/00 Primary

  Subject matter not provided for in other groups of this subclass · CPC title