METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20110287580A1
• Filed: 05/13/2011
• Published: 11/24/2011
• Est. Priority Date: 05/20/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei, SUZAWA, Hideomi, SASAGAWA, Shinya
• Granted Patent: US 9,496,405 B2
• Time in Patent Office: Days
• US Class Current: 438/104
• 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

Abstract

An object of an embodiment of the present invention is to provide a semiconductor device including a normally-off oxide semiconductor element whose characteristic variation is small in the long term. A cation containing one or more elements selected from oxygen and halogen is added to an oxide semiconductor layer, thereby suppressing elimination of oxygen, reducing hydrogen, or suppressing movement of hydrogen. Accordingly, carriers in the oxide semiconductor can be reduced and the number of the carriers can be kept constant in the long term. As a result, the semiconductor device including the normally-off oxide semiconductor element whose characteristic variation is small in the long term can be provided.

Claims

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

forming a first conductive layer functioning as a gate electrode over an insulator;

forming a first insulating layer covering the first conductive layer;

forming an oxide semiconductor layer over the first insulating layer so that part of the oxide semiconductor layer overlaps with the first conductive layer;

forming second conductive layers each electrically connected to the oxide semiconductor layer and including a source electrode and a drain electrode;

forming a second insulating layer covering the oxide semiconductor layer and the second conductive layers; and

adding a cation containing one or more elements selected from oxygen and halogen to the oxide semiconductor layer.

2. The method for manufacturing the semiconductor device according to claim 1, wherein the oxide semiconductor layer containing indium, gallium, and zinc is formed in the step of forming the oxide semiconductor layer.

3. The method for manufacturing the semiconductor device according to claim 1, the method further comprises a step of performing heat treatment on the oxide semiconductor layer at a temperature higher than or equal to 100°

C. and lower than or equal to 500°

C. in a period from the step of forming the oxide semiconductor layer to the step of forming the second insulating layer, or after the step of forming the second insulating layer.

4. The method for manufacturing the semiconductor device according to claim 1, wherein the step of adding the cation to the oxide semiconductor layer is performed in a period from the step of forming the oxide semiconductor layer to a timing before the step of forming the second insulating layer.

5. The method for manufacturing the semiconductor device according to claim 1, the method further comprises a step of adding a second cation containing one or more elements selected from oxygen and halogen to the first insulating layer.

6. The method for manufacturing the semiconductor device according to claim 1, the method further comprises a step of adding a third cation containing one or more elements selected from oxygen and halogen to the second insulating layer.

7. The method for manufacturing the semiconductor device according to claim 1, wherein the step of adding the cation is performed by one selected from an electron cyclotron resonance (ECR) plasma method, a helicon wave plasma (HWP) method, an inductively coupled plasma (ICP) method, and a microwave-excited surface wave plasma (SWP) method;

or a combination thereof.

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

forming an oxide semiconductor layer over an insulator;

forming first conductive layers each electrically connected to the oxide semiconductor layer and including a source electrode and a drain electrode;

forming an insulating layer covering the oxide semiconductor layer and the first conductive layers;

forming a second conductive layer functioning a gate electrode over the insulating layer so that part of the second conductive layer overlaps with the oxide semiconductor layer; and

adding a cation containing one or more elements selected from oxygen and halogen to the oxide semiconductor layer.

9. The method for manufacturing the semiconductor device according to claim 8, wherein the oxide semiconductor layer containing indium, gallium, and zinc is formed in the step of forming the oxide semiconductor layer.

10. The method for manufacturing the semiconductor device according to claim 8, the method further comprises a step of performing heat treatment on the oxide semiconductor layer at a temperature higher than or equal to 100°

C. and lower than or equal to 500°

C. in a period from the step of forming the oxide semiconductor layer to the step of forming the second conductive layer, or after the step of forming the second conductive layer.

11. The method for manufacturing the semiconductor device according to claim 8, wherein the step of adding the cation to the oxide semiconductor layer is performed in a period from the step of forming the oxide semiconductor layer to a timing before the step of forming the insulating layer.

12. The method for manufacturing the semiconductor device according to claim 8, the method further comprises a step of adding a second cation containing one or more elements selected from oxygen and halogen to the insulator.

13. The method for manufacturing the semiconductor device according to claim 8, further comprising a step of adding a third cation containing one or more elements selected from oxygen and halogen to the insulating layer.

14. The method for manufacturing the semiconductor device according to claim 8, wherein the step of adding the cation is performed by one selected from an electron cyclotron resonance (ECR) plasma method, a helicon wave plasma (HWP) method, an inductively coupled plasma (ICP) method, and a microwave-excited surface wave plasma (SWP) method;

or a combination thereof.