METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20110008930A1
• Filed: 06/29/2010
• Published: 01/13/2011
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei, SASAKI, Toshinari, SAKATA, Junichiro, OHARA, Hiroki
• Granted Patent: US 8,207,014 B2
• Time in Patent Office: Days
• US Class Current: 438/104
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02664 Aftertreatments planarisation in general H01L21/304
• CPC Class Codes: H01L 21/383 using diffusion into or out of a solid from or into a gaseous phase
• CPC Class Codes: H01L 21/46 Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/428 manufacture of electrodes thereon H01L21/44
• CPC Class Codes: H01L 21/477 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/38 - H01L21/449 and H01L21/461 - H01L21/475 take precedence
• 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 29/66969 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

An object is to manufacture a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which an oxide semiconductor film is used for a semiconductor layer including a channel formation region, heat treatment (for dehydration or dehydrogenation) is performed to improve the purity of the oxide semiconductor film and reduce impurities including moisture or the like. After that, slow cooling is performed under an oxygen atmosphere. Besides impurities including moisture or the like exiting in the oxide semiconductor film, heat treatment causes reduction of impurities including moisture or the like exiting in a gate insulating layer and those in interfaces between the oxide semiconductor film and films which are provided over and below the oxide semiconductor and in contact therewith.

Claims

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

forming an oxide semiconductor layer on an insulating layer;

performing dehydration or dehydrogenation on the oxide semiconductor layer and then cooling the oxide semiconductor layer in an oxygen atmosphere;

forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer after dehydration or dehydrogenation have been performed on the oxide semiconductor layer; and

forming an oxide insulating film over the insulating layer, the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and in contact with part of the oxide semiconductor layer.

2. The method for manufacturing a semiconductor device, according to claim 1, further comprising the steps of:

forming a gate electrode layer; and

forming the insulating layer over the gate electrode layer.

3. The method for manufacturing a semiconductor device, according to claim 1, wherein the dehydration or dehydrogenation step comprises a heat treatment performed in an atmosphere of nitrogen or a rare gas, or under reduced pressure.

14. The method for manufacturing a semiconductor device according claim 1, wherein a carrier concentration of the oxide semiconductor layer is increased is higher than or equal to 1×

10¹⁸/cm³.

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

forming an oxide semiconductor layer over an insulating layer;

heating the oxide semiconductor layer so as to decrease a hydrogen concentration in the oxide semiconductor layer and then cooling the oxide semiconductor layer in an oxygen atmosphere;

forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer after dehydration or dehydrogenation have been performed on the oxide semiconductor layer; and

forming an oxide insulating film over the insulating layer, the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and in contact with part of the oxide semiconductor layer.

5. The method for manufacturing a semiconductor device, according to claim 4, further comprising the steps of:

forming a gate electrode layer; and

forming the insulating layer over the gate electrode layer.

6. The method for manufacturing a semiconductor device, according to claim 4, wherein the step of heating the oxide semiconductor layer so as to decrease a hydrogen concentration in the oxide semiconductor layer is performed in an atmosphere of nitrogen or a rare gas, or under reduced pressure.

15. The method for manufacturing a semiconductor device according claim 4, wherein a carrier concentration of the oxide semiconductor layer is increased is higher than or equal to 1×

10¹⁸/cm³.

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

forming an oxide semiconductor layer over an insulating layer;

heating the oxide semiconductor layer in an inert atmosphere so that a carrier concentration of the oxide semiconductor layer is increased, and then slowly cooling the oxide semiconductor layer in an oxygen atmosphere;

forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer after having increased the carrier concentration of the oxide semiconductor layer; and

forming an oxide insulating film over the insulating layer, the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and in contact with part of the oxide semiconductor layer, after having performed the heat treatment on the oxide semiconductor layer, whereby the carrier concentration of the oxide semiconductor layer is reduced.

8. The method for manufacturing a semiconductor device, according to claim 7, further comprising the steps of:

forming a gate electrode layer; and

forming the insulating layer over the gate electrode layer.

9. The method for manufacturing a semiconductor device, according to claim 7, wherein the inert atmosphere is an atmosphere comprising nitrogen or a rare gas.

10. The method for manufacturing a semiconductor device, according to claim 7, wherein the oxide semiconductor layer is heated in the inert atmosphere at a temperature higher than or equal to 400°

C.

11. The method for manufacturing a semiconductor device, according to claim 7, wherein the oxide semiconductor layer is heated in the inert atmosphere at a temperature higher than or equal to 400°

C. and then cooled to a temperature higher than or equal to room temperature and lower than 100°

C.

16. The method for manufacturing a semiconductor device according claim 7, wherein a carrier concentration of the oxide semiconductor layer is increased is higher than or equal to 1×

10¹⁸/cm³.

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

forming an oxide semiconductor layer over an insulating layer;

performing a heat treatment on the oxide semiconductor layer by heating the oxide semiconductor under reduced pressure so that a carrier concentration of the oxide semiconductor layer is increased and then cooling the oxide semiconductor layer in an oxygen atmosphere;

forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer after having increased the carrier concentration of the oxide semiconductor layer; and

forming an oxide insulating film over the insulating layer, the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and in contact with part of the heated oxide semiconductor layer, after having performed the heat treatment on the oxide semiconductor layer, whereby the carrier concentration of the oxide semiconductor layer is reduced.

13. The method for manufacturing a semiconductor device, according to claim 12, further comprising the steps of:

forming a gate electrode layer; and

forming the insulating layer over the gate electrode layer.

17. The method for manufacturing a semiconductor device according claim 12, wherein a carrier concentration of the oxide semiconductor layer is increased is higher than or equal to 1×

10¹⁸/cm³.