Semiconductor device and method for manufacturing the same

• US 9,496,416 B2
• Filed: 06/16/2015
• Issued: 11/15/2016
• Est. Priority Date: 04/09/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Harrison, Monica D
• Application Number:
  US14/740,615
• Publication Number:
  US 20150311352A1
• Time in Patent Office: 518 Days
• Field of Search: 257/43
• US Class Current: 1/1
• CPC Class Codes: H01L 29/42384 for thin film field effect transistors, e.g. characterised by the thickness or the shape of the insulator or the dimensions, the shape or the lay-out of the conductor
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/78648 arranged on opposing sides of the channel
• 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

An object is to manufacture a semiconductor device with high reliability by providing the semiconductor device including an oxide semiconductor with stable electric characteristics. In a transistor including an oxide semiconductor layer, a gallium oxide film is used for a gate insulating layer and made in contact with an oxide semiconductor layer. Further, gallium oxide films are provided so as to sandwich the oxide semiconductor layer, whereby reliability is increased. Furthermore, the gate insulating layer may have a stacked structure of a gallium oxide film and a hafnium oxide film.

Claims

1. A semiconductor device comprising:

a first gate electrode over a substrate;

a first metal oxide film comprising gallium oxide over the first gate electrode;

an oxide semiconductor layer comprising indium, gallium and zinc over the first metal oxide film;

a source electrode and a drain electrode over and electrically connected to the oxide semiconductor layer;

a second metal oxide film comprising gallium oxide over the oxide semiconductor layer, the source electrode, and the drain electrode; and

a second gate electrode over the second metal oxide film.

2. The semiconductor device according to claim 1, wherein the first metal oxide film and the second metal oxide film are each an insulating film.

3. The semiconductor device according to claim 1, wherein the second gate electrode does not overlap with the source electrode and the drain electrode.

4. The semiconductor device according to claim 1, wherein a carrier concentration of the oxide semiconductor layer is lower than 1×

10¹⁴/cm³.

5. The semiconductor device according to claim 1, further comprising a first film comprising hafnium between the first gate electrode and the first metal oxide film and a second film comprising hafnium between the second metal oxide film and the second gate electrode.

6. The semiconductor device according to claim 5, wherein each of the first film and the second film is one selected from a hafnium oxide film, a hafnium silicate film, a hafnium oxynitride silicate film, and a hafnium aluminate film.

7. A semiconductor device comprising:

a first gate electrode over a substrate;

a first metal oxide film comprising gallium oxide over the first gate electrode;

an oxide semiconductor layer comprising indium, gallium and zinc over the first metal oxide film;

a source electrode and a drain electrode over and electrically connected to the oxide semiconductor layer;

a second metal oxide film comprising gallium oxide over the oxide semiconductor layer, the source electrode, and the drain electrode; and

a second gate electrode over the second metal oxide film,

wherein the first metal oxide film and the second metal oxide film are in contact with each other.

8. The semiconductor device according to claim 7, wherein the second metal oxide film is in contact with a top surface of the first metal oxide film.

9. The semiconductor device according to claim 7, wherein the first metal oxide film and the second metal oxide film are each an insulating film.

10. The semiconductor device according to claim 7, wherein the second gate electrode does not overlap with the source electrode and the drain electrode.

11. The semiconductor device according to claim 7, wherein a carrier concentration of the oxide semiconductor layer is lower than 1×

10¹⁴/cm³.

12. The semiconductor device according to claim 7, further comprising a first film comprising hafnium between the first gate electrode and the first metal oxide film and a second film comprising hafnium between the second metal oxide film and the second gate electrode.

13. The semiconductor device according to claim 12, wherein each of the first film and the second film is one selected from a hafnium oxide film, a hafnium silicate film, a hafnium oxynitride silicate film, and a hafnium aluminate film.

14. A semiconductor device comprising:

a first gate electrode over a substrate;

a film comprising hafnium oxide over the first gate electrode;

a first metal oxide film comprising gallium oxide over the film comprising hafnium oxide;

an oxide semiconductor layer comprising indium, gallium and zinc over the first metal oxide film;

a source electrode and a drain electrode over and electrically connected to the oxide semiconductor layer;

a second metal oxide film comprising gallium oxide over the oxide semiconductor layer, the source electrode, and the drain electrode; and

a second gate electrode over the second metal oxide film.

15. The semiconductor device according to claim 14, wherein the first metal oxide film and the second metal oxide film are each an insulating film.

16. The semiconductor device according to claim 14, wherein the second gate electrode does not overlap with the source electrode and the drain electrode.

17. The semiconductor device according to claim 14, wherein a carrier concentration of the oxide semiconductor layer is lower than 1×

10¹⁴/cm³.

18. The semiconductor device according to claim 14, further comprising a film comprising hafnium between the second metal oxide film and the second gate electrode.

19. The semiconductor device according to claim 18, wherein the film comprising hafnium is one selected from a hafnium oxide film, a hafnium silicate film, a hafnium oxynitride silicate film, and a hafnium aluminate film.

20. A semiconductor device comprising:

a first gate electrode over a substrate;

a first metal oxide film over the first gate electrode;

an oxide semiconductor layer over the first metal oxide film;

a source electrode and a drain electrode electrically connected to the oxide semiconductor layer;

a second metal oxide film over the oxide semiconductor layer; and

a second gate electrode over the second metal oxide film,

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

21. The semiconductor device according to claim 20, wherein the first metal oxide film and the second metal oxide film are each an insulating film.

22. The semiconductor device according to claim 20, wherein the second gate electrode does not overlap with the source electrode and the drain electrode.

23. The semiconductor device according to claim 20, wherein a carrier concentration of the oxide semiconductor layer is lower than 1×

10¹⁴/cm³.

24. The semiconductor device according to claim 20, further comprising a film comprising hafnium between the second metal oxide film and the second gate electrode.

25. The semiconductor device according to claim 24, wherein the film comprising hafnium is one selected from a hafnium oxide film, a hafnium silicate film, a hafnium oxynitride silicate film, and a hafnium aluminate film.