Semiconductor device and method for manufacturing the same

• US 8,980,665 B2
• Filed: 12/31/2012
• Issued: 03/17/2015
• Est. Priority Date: 11/07/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Sakata, Junichiro
• Primary Examiner(s): Tran, Long K
• Application Number:
  US13/731,546
• Publication Number:
  US 20130122666A1
• Time in Patent Office: 806 Days
• Field of Search: 438/30, 438/31, 438/48, 257/E51.005, 257/E29.151
• US Class Current: 438/48
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• 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 29/78669 with inverted-type structure, e.g. with bottom gate
• CPC Class Codes: H01L 29/78678 with inverted-type structure, e.g. with bottom gate
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

It is an object to provide a highly reliable semiconductor device including a thin film transistor whose electric characteristics are stable. In addition, it is another object to manufacture a highly reliable semiconductor device at low cost with high productivity. In a semiconductor device including a thin film transistor, a semiconductor layer of the thin film transistor is formed with an oxide semiconductor layer to which a metal element is added. As the metal element, at least one of metal elements of iron, nickel, cobalt, copper, gold, manganese, molybdenum, tungsten, niobium, and tantalum is used. In addition, the oxide semiconductor layer contains indium, gallium, and zinc.

Claims

1. A method for manufacturing a semiconductor device, comprising the steps of:

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming an oxide semiconductor layer over the gate insulating layer;

performing a plasma treatment under an atmosphere containing Cl₂ on the oxide semiconductor layer;

forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer; and

adding a metal element to a first region which is not covered with the source electrode layer or the drain electrode layer in the oxide semiconductor layer.

2. The method for manufacturing a semiconductor device according to claim 1,

wherein the metal element is not added to a second region in the oxide semiconductor layer, and

wherein the second region is between the first region and the gate insulating layer.

3. The method for manufacturing a semiconductor device according to claim 1, further comprising the step of forming an insulating film so as to cover the oxide semiconductor layer, the source electrode layer, and the drain electrode layer,

wherein the insulating film is formed in contact with the oxide semiconductor layer.

4. The method for manufacturing a semiconductor device according to claim 1, wherein the metal element is at least one selected from the group consisting of iron, nickel, cobalt, copper, gold, manganese, molybdenum, tungsten, niobium, and tantalum.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the metal element is added by an ion implantation method.

6. A method for manufacturing a semiconductor device, comprising the steps of:

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming an oxide semiconductor layer over the gate insulating layer;

performing a plasma treatment under an atmosphere containing Cl₂ on the oxide semiconductor layer;

adding a metal element to the oxide semiconductor layer; and

forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer.

7. The method for manufacturing a semiconductor device according to claim 6,

wherein the metal element is added to a first region in the oxide semiconductor layer,

wherein the metal element is not added to a second region in the oxide semiconductor layer, and

wherein the second region is between the first region and the gate insulating layer.

8. The method for manufacturing a semiconductor device according to claim 6, further comprising the step of forming an insulating film so as to cover the oxide semiconductor layer, the source electrode layer, and the drain electrode layer,

wherein the insulating film is formed in contact with the oxide semiconductor layer.

9. The method for manufacturing a semiconductor device according to claim 6, wherein the metal element is at least one selected from the group consisting of iron, nickel, cobalt, copper, gold, manganese, molybdenum, tungsten, niobium, and tantalum.

10. The method for manufacturing a semiconductor device according to claim 6, wherein the metal element is added by an ion implantation method.

11. A method for manufacturing a semiconductor device, comprising the steps of:

forming an oxide semiconductor layer;

performing a plasma treatment under an atmosphere containing Cl₂ on the oxide semiconductor layer; and

adding a metal element to the oxide semiconductor layer.

12. The method for manufacturing a semiconductor device according to claim 11, wherein the metal element is at least one selected from the group consisting of iron, nickel, cobalt, copper, gold, manganese, molybdenum, tungsten, niobium, and tantalum.

13. The method for manufacturing a semiconductor device according to claim 11,

wherein the oxide semiconductor layer comprises a first region and a second region,

wherein the first region contains the metal element,

wherein the second region does not contain the metal element, and

wherein the first region is formed in a surface of the oxide semiconductor layer.

14. The method for manufacturing a semiconductor device according to claim 11, wherein the metal element is added by an ion implantation method.

15. The method for manufacturing a semiconductor device according to claim 11, further comprising the step of performing an oxygen radical treatment on the oxide semiconductor layer.

16. The method for manufacturing a semiconductor device according to claim 15, wherein the oxygen radical treatment is performed under an atmosphere containing N₂O.