SEMICONDUCTOR DEVICE

• US 20110240990A1
• Filed: 03/29/2011
• Published: 10/06/2011
• Est. Priority Date: 04/02/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Granted Patent: US 8,502,221 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 27/1222 with a particular composition, shape or crystalline structure of the active layer
• 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 29/786 Thin film transistors, i.e. transistors with a channel being at least partly a thin film transistors having only the source or the drain region on an insulator layer H01L29/0653; thin film FinFETs H01L29/785
• 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
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

An object is to stabilize electric characteristics of a semiconductor device including an oxide semiconductor to increase reliability. The semiconductor device includes an insulating film; a first metal oxide film on and in contact with the insulating film; an oxide semiconductor film partly in contact with the first metal oxide film; source and drain electrodes electrically connected to the oxide semiconductor film; a second metal oxide film partly in contact with the oxide semiconductor film; a gate insulating film on and in contact with the second metal oxide film; and a gate electrode over the gate insulating film.

Claims

1. A semiconductor device comprising:

an insulating film;

a first metal oxide film on and in contact with the insulating film;

an oxide semiconductor film partly in contact with the first metal oxide film;

source and drain electrodes electrically connected to the oxide semiconductor film;

a second metal oxide film partly in contact with the oxide semiconductor film;

a gate insulating film on and in contact with the second metal oxide film; and

a gate electrode over the gate insulating film.

2. The semiconductor device according to claim 1,

wherein the first metal oxide film and the second metal oxide film each contain a constituent element of the oxide semiconductor film.

3. The semiconductor device according to claim 1,

wherein the first metal oxide film and the second metal oxide film each have a larger energy gap than the oxide semiconductor film.

4. The semiconductor device according to claim 1,

wherein energy at a bottom of a conduction band of each of the first metal oxide film and the second metal oxide film is higher than energy at a bottom of a conduction band of the oxide semiconductor film.

5. The semiconductor device according to claim 1,

wherein the first metal oxide film and the second metal oxide film each contain a gallium oxide.

6. The semiconductor device according to claim 1,

wherein a proportion of a constituent element of the first metal oxide film is equal to a proportion of a constituent element of the second metal oxide film.

7. The semiconductor device according to claim 1,

wherein the insulating film contains a silicon oxide.

8. The semiconductor device according to claim 1,

wherein the gate insulating film contains a silicon oxide or a hafnium oxide.

9. The semiconductor device according to claim 1,

wherein the second metal oxide film is provided so as to cover the source and drain electrodes and contact the first metal oxide film.

10. The semiconductor device according to claim 9,

wherein the oxide semiconductor film is surrounded by the first metal oxide film and the second metal oxide film.

11. The semiconductor device according to claim 1,

wherein side edges of the oxide semiconductor film in a channel length direction are aligned with side edges of the first metal oxide film in a channel length direction.

12. The semiconductor device according to claim 1,

wherein side edges of the oxide semiconductor film in a channel length direction are aligned with side edges of the second metal oxide film in a channel length direction.

13. The semiconductor device according to claim 1,

wherein a first insulating film is provided so as to cover the gate insulating film and the gate electrode.

14. The semiconductor device according to claim 1,

wherein a conductive film is provided below the oxide semiconductor film.