Semiconductor device

• US 10,158,005 B2
• Filed: 12/03/2013
• Issued: 12/18/2018
• Est. Priority Date: 11/07/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Akimoto, Kengo, Yamazaki, Shunpei
• Primary Examiner(s): Payen, Marvin
• Application Number:
  US14/095,189
• Publication Number:
  US 20140087517A1
• Time in Patent Office: 1,841 Days
• Field of Search: 438104
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

An object is to prevent an impurity such as moisture and oxygen from being mixed into an oxide semiconductor and suppress variation in semiconductor characteristics of a semiconductor device in which an oxide semiconductor is used. Another object is to provide a semiconductor device with high reliability. A gate insulating film provided over a substrate having an insulating surface, a source and a drain electrode which are provided over the gate insulating film, a first oxide semiconductor layer provided over the source electrode and the drain electrode, and a source and a drain region which are provided between the source electrode and the drain electrode and the first oxide semiconductor layer are provided. A barrier film is provided in contact with the first oxide semiconductor layer.

Claims

1. A method of manufacturing a semiconductor device comprising:

forming a gate electrode layer;

forming a gate insulating layer over the gate electrode layer;

forming an oxide semiconductor layer over the gate electrode layer with the gate insulating layer interposed therebetween, the oxide semiconductor layer comprising a channel formation region;

forming a conductive film on the oxide semiconductor layer, the conductive film comprising an alloy including copper and manganese;

heating the conductive film after forming the conductive film;

etching the conductive film to form a first conductive layer and a second conductive layer;

forming an insulating film over the first conductive layer and the second conductive layer, wherein the insulating film is in contact with a portion of the oxide semiconductor layer between the first conductive layer and the second conductive layer.

2. The method according to claim 1, wherein the insulating film comprises aluminum and oxygen.

3. The method according to claim 1, wherein the insulating film comprises silicon and oxygen.

4. The method according to claim 1, wherein the oxide semiconductor layer contains sodium at a concentration less than or equal to 5×

10¹⁹/cm³.

5. The method according to claim 1, wherein the oxide semiconductor layer comprises In, Ga and Zn.

6. The method according to claim 1, further comprising a step of forming a pixel electrode electrically connected to one of the first conductive layer and the second conductive layer.

7. The method according to claim 1, wherein the step of heating the conductive film is performed at 200°

C. to 600°

C.

8. A method of manufacturing a semiconductor device comprising:

forming a gate electrode layer;

forming a gate insulating layer over the gate electrode layer;

forming an oxide semiconductor layer over the gate electrode layer with the gate insulating layer interposed therebetween, the oxide semiconductor layer comprising a channel formation region;

forming a conductive film on the oxide semiconductor layer, the conductive film comprising an alloy including copper and manganese;

heating the conductive film after forming the conductive layer;

etching the conductive film to form a first conductive layer and a second conductive layer;

etching a portion of the oxide semiconductor layer between the first conductive layer and the second conductive layer so that the oxide semiconductor layer is thinner in a region between the first conductive layer and the second conductive layer than in regions below the first conductive layer and the second conductive layer;

forming an insulating film over the first conductive layer and the second conductive layer, wherein the insulating film is in contact with a portion of the oxide semiconductor layer between the first conductive layer and the second conductive layer.

9. The method according to claim 8, wherein the insulating film comprises aluminum and oxygen.

10. The method according to claim 8, wherein the insulating film comprises silicon and oxygen.

11. The method according to claim 8, wherein the oxide semiconductor layer contains sodium at a concentration less than or equal to 5×

10¹⁹/cm³.

12. The method according to claim 8, wherein the oxide semiconductor layer comprises In, Ga and Zn.

13. The method according to claim 8, further comprising a step of forming a pixel electrode electrically connected to one of the first conductive layer and the second conductive layer.

14. The method according to claim 8, wherein the step of heating the conductive film is performed at 200°

C. to 600°

C.

15. A method of manufacturing a semiconductor device comprising:

forming a gate electrode layer;

forming a gate insulating layer over the gate electrode layer;

forming a first oxide semiconductor layer over the gate electrode layer with the gate insulating layer interposed therebetween, the first oxide semiconductor layer comprising a channel formation region;

forming a second oxide semiconductor layer over the first oxide semiconductor layer;

forming a conductive film on the second oxide semiconductor layer, the conductive layer comprising an alloy including copper and manganese;

heating the conductive film after forming the conductive layer;

etching the conductive film to form a first conductive layer and a second conductive layer;

etching a portion of the second oxide semiconductor layer between the first conductive layer and the second conductive layer to form a source region and a drain region;

forming an insulating film over the first conductive layer and the second conductive layer, wherein the insulating film is in contact with a portion of the first oxide semiconductor layer between the first conductive layer and the second conductive layer.

16. The method according to claim 15, wherein the insulating film comprises aluminum and oxygen.

17. The method according to claim 15, wherein the insulating film comprises silicon and oxygen.

18. The method according to claim 15, wherein the first oxide semiconductor layer contains sodium at a concentration less than or equal to 5×

10¹⁹/cm³.

19. The method according to claim 15, wherein the first oxide semiconductor layer comprises In, Ga and Zn.

20. The method according to claim 15, further comprising a step of forming a pixel electrode electrically connected to one of the first conductive layer and the second conductive layer.

21. The method according to claim 15, wherein the step of heating the conductive film is performed at 200°

C. to 600°

C.