Semiconductor device having an oxide semiconductor

Patent metadata

Field	Value
Publication number	US-9190522-B2
Application number	US-201113074658-A
Country	US
Kind code	B2
Filing date	Mar 29, 2011
Priority date	Apr 2, 2010
Publication date	Nov 17, 2015
Grant date	Nov 17, 2015

Abstract

An object is to provide a semiconductor device including an oxide semiconductor, which has stable electric characteristics and high reliability. A semiconductor device includes an oxide semiconductor film, a source electrode and a drain electrode which are electrically connected to the oxide semiconductor film, a metal oxide film which is partly in contact with the oxide semiconductor film, a gate insulating film which is over and in contact with the metal oxide film, and a gate electrode over the gate insulating film. With such a structure, effect of charge on the oxide semiconductor film can be relaxed; thus, shift of the threshold voltage in the transistor, due to charge trapping at an interface of the oxide semiconductor film, can be suppressed.

First claim

What is claimed is:

1. A semiconductor device comprising:
an oxide semiconductor film comprising a channel formation region;
a source electrode and a drain electrode over and electrically connected to the oxide semiconductor film;
a gallium oxide film over the oxide semiconductor film, the source electrode and the drain electrode;
a gate insulating film over and in contact with the gallium oxide film; and
a gate electrode over the gate insulating film,
wherein the gate electrode and the channel formation region overlap each other with the gate insulating film therebetween, and
wherein the gallium oxide film is in contact with an outer side surface of each of the source electrode and the drain electrode.

2. The semiconductor device according to claim 1 , wherein an energy gap of the gallium oxide film is larger than an energy gap of the oxide semiconductor film.

3. The semiconductor device according to claim 1 , wherein an energy at a bottom of a conduction band of the gallium oxide film is higher than an energy at a bottom of a conduction band of the oxide semiconductor film.

4. The semiconductor device according to claim 1 , wherein the gate insulating film comprises silicon oxide or hafnium oxide.

5. The semiconductor device according to claim 1 , wherein the gate insulating film comprises aluminum oxide or aluminum nitride.

6. The semiconductor device according to claim 1 , wherein at least a part of a top surface of the oxide semiconductor film is in contact with the source electrode and the drain electrode.

7. The semiconductor device according to claim 1 , further comprising an insulating film that covers the gate insulating film and the gate electrode.

8. The semiconductor device according to claim 1 , wherein the gallium oxide film is in contact with a top surface of the oxide semiconductor film between the source electrode and the drain electrode.

9. The semiconductor device according to claim 1 , wherein the gallium oxide film is in contact with side surfaces of the oxide semiconductor film in a channel width direction.

10. A semiconductor device comprising:
an oxide semiconductor film comprising a channel formation region;
a source electrode and a drain electrode over and electrically connected to the oxide semiconductor film;
a metal oxide film over the oxide semiconductor film, the source electrode and the drain electrode;
a gate insulating film on and in contact with the metal oxide film; and
a gate electrode over the gate insulating film,
wherein the gate electrode and the channel formation region overlap each other with the gate insulating film therebetween,
wherein the metal oxide film is in contact with an outer side surface of each of the source electrode and the drain electrode, and
wherein the metal oxide film comprises one or more metal elements included in the oxide semiconductor film.

11. The semiconductor device according to claim 10 , wherein an energy gap of the metal oxide film is larger than an energy gap of the oxide semiconductor film.

12. The semiconductor device according to claim 10 , wherein an energy at a bottom of a conduction band of the metal oxide film is higher than an energy at a bottom of a conduction band of the oxide semiconductor film.

13. The semiconductor device according to claim 10 , wherein the metal oxide film comprises gallium.

14. The semiconductor device according to claim 10 , wherein the gate insulating film comprises silicon oxide or hafnium oxide.

15. The semiconductor device according to claim 10 , wherein the gate insulating film comprises aluminum oxide or aluminum nitride.

16. The semiconductor device according to claim 10 , wherein at least a part of a top surface of the oxide semiconductor film is in contact with the source electrode and the drain electrode.

17. The semiconductor device according to claim 10 , further comprising an insulating film that covers the gate insulating film and the gate electrode.

18. The semiconductor device according to claim 10 , wherein the metal oxide film is in contact with a top surface of the oxide semiconductor film between the source electrode and the drain electrode.

19. The semiconductor device according to claim 10 , wherein the metal oxide film is in contact with side surfaces of the oxide semiconductor film in a channel width direction.

Assignees

• Yamazaki Shunpei
• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei

Classifications

• H10D30/6704

  having supplementary regions or layers in the thin films or in the insulated bulk substrates for controlling properties of the device · CPC title

• H10D30/6755 Primary

  Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate · CPC title

• H01L29/7869 Primary

  Electricity · mapped topic

• H01L29/78606

  Electricity · mapped topic