Semiconductor Device and Method for Manufacturing the Same

• US 20100258802A1
• Filed: 04/05/2010
• Published: 10/14/2010
• Est. Priority Date: 04/10/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: GODO, Hiromichi, INOUE, Takayuki
• Granted Patent: US 8,441,047 B2
• Time in Patent Office: Days
• US Class Current: 257/57
• 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

An object is to provide an n-channel transistor and a p-channel transistor having a preferred structure using an oxide semiconductor. A first source or drain electrode which is electrically connected to a first oxide semiconductor layer and is formed using a stacked-layer structure including a first conductive layer containing a first material and a second conductive layer containing a second material, and a second source or drain electrode which is electrically connected to a second oxide semiconductor layer and is formed using a stacked-layer structure including a third conductive layer containing the first material and a fourth conductive layer containing the second material are included. The first oxide semiconductor layer is in contact with the first conductive layer of the first source or drain electrode, and the second oxide semiconductor layer is in contact with the third and the fourth conductive layers of the second source or drain electrode.

Claims

1. A semiconductor device comprising:

a first gate electrode and a second gate electrode over a substrate;

a gate insulating layer covering the first gate electrode and the second gate electrode;

a first oxide semiconductor layer provided over the gate insulating layer and overlapping with the first gate electrode;

a first source electrode or drain electrode provided over, and electrically connected to the first oxide semiconductor layer, wherein the first source electrode or drain electrode comprises a first conductive layer containing a first material and a second conductive layer containing a second material over the first conductive layer;

a second source electrode or drain electrode provided over the gate insulating layer, wherein the second source electrode or drain electrode comprises a third conductive layer containing the first material and a fourth conductive layer containing the second material over the third conductive layer, and

a second oxide semiconductor layer provided over and electrically connected to the second source electrode or drain electrode, and overlapping with the second gate electrode.

3. The semiconductor device according to claim 1, wherein part of the first oxide semiconductor layer functions as a channel formation region of a p-channel transistor, and wherein part of the second oxide semiconductor layer functions as a channel formation region of an n-channel transistor.

5. The semiconductor device according to claim 1, wherein the first material is a material which forms a Schottky barrier of 0.5 eV or lower between the first material and the first oxide semiconductor layer, and wherein the second material is a material which forms a Schottky barrier of 0.5 eV or lower between the second material and the second oxide semiconductor layer.

7. The semiconductor device according to claim 1, wherein the first material is a material whose work function is higher than 5.0 eV, and wherein the second material is a material whose work function is lower than 4.8 eV.

9. The semiconductor device according to claim 1, wherein the first gate electrode is electrically connected to the second gate electrode, and wherein the first source electrode or drain electrode is electrically connected to the second source electrode or drain electrode.

11. The semiconductor device according to claim 1, wherein the first oxide semiconductor layer is in contact with the first conductive layer, and the second oxide semiconductor layer is in contact with the third conductive layer and the fourth conductive layer.

13. The semiconductor device according to claim 1, wherein the first oxide semiconductor layer comprises a material selected from the group consisting of a tin oxide, a zinc oxide, a nickel oxide, a copper aluminum oxide, and a strontium copper oxide.

15. The Semiconductor device according to claim 1, wherein the second oxide semiconductor layer comprises a substance represented by InMO₃(ZnO)_m, where m is larger than 0, and M denotes one or more of metal elements selected from gallium, iron, nickel, manganese, cobalt.

17. The semiconductor device according to claim 1, wherein the first material is a material selected from the group consisting of gold, platinum, nickel, copper, cobalt, and an indium tin oxide.

19. The semiconductor device according to claim 1, wherein the second material is a material selected from the group consisting of titanium, aluminum, molybdenum, and tungsten.

2. A semiconductor device comprising:

a first gate electrode and a second gate electrode over a substrate;

a gate insulating layer covering the first gate electrode and the second gate electrode;

a first oxide semiconductor layer provided over the gate insulating layer and overlapping with the first gate electrode;

a first source electrode or drain electrode provided over, and electrically connected to the first oxide semiconductor layer, wherein the first source electrode or drain electrode comprises a first conductive layer containing a first material and a second conductive layer containing a second material over the first conductive layer;

a second source electrode or drain electrode provided over the gate insulating layer, wherein the second source electrode or drain electrode comprises a third conductive layer containing the second material, and a second oxide semiconductor layer provided over and electrically connected to the second source electrode or drain electrode, and overlapping with the second gate electrode.

4. The semiconductor device according to claim 2, wherein part of the first oxide semiconductor layer functions as a channel formation region of a p-channel transistor, and wherein part of the second oxide semiconductor layer functions as a channel formation region of an n-channel transistor.

6. The semiconductor device according to claim 2, wherein the first material is a material which forms a Schottky barrier of 0.5 eV or lower between the first material and the first oxide semiconductor layer, and wherein the second material is a material which forms a Schottky barrier of 0.5 eV or lower between the second material and the second oxide semiconductor layer.

8. The semiconductor device according to claim 2, wherein the first material is a material whose work function is higher than 5.0 eV, and wherein the second material is a material whose work function is lower than 4.8 eV.

10. The semiconductor device according to claim 2, wherein the first gate electrode is electrically connected to the second gate electrode, and wherein the first source electrode or drain electrode is electrically connected to the second source electrode or drain electrode.

12. The semiconductor device according to claim 2, wherein the first oxide semiconductor layer is in contact with the first conductive layer, and the second oxide semiconductor layer is in contact with the third conductive layer.

14. The semiconductor device according to claim 2, wherein the first oxide semiconductor layer comprises a material selected from the group consisting of a tin oxide, a zinc oxide, a nickel oxide, a copper aluminum oxide, and a strontium copper oxide.

16. The semiconductor device according to claim 2, wherein the second oxide semiconductor layer comprises a substance represented by InMO₃(ZnO)_m, where m is larger than 0, and M denotes one or more of metal elements selected from gallium, iron, nickel, manganese, cobalt.

18. The semiconductor device according to claim 2, wherein the first material is a material selected from the group consisting of gold, platinum, nickel, copper, cobalt, and an indium tin oxide.

20. The semiconductor device according to claim 2, wherein the second material is a material selected from the group consisting of titanium, aluminum, molybdenum, and tungsten.

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

forming a first gate electrode and a second gate electrode over a substrate;

forming a gate insulating layer to cover the first gate electrode and the second gate electrode;

forming a first oxide semiconductor layer in a region which overlaps with the first gate electrode, over the gate insulating layer;

forming a first conductive layer over an entire surface of the substrate to cover the first oxide semiconductor layer;

forming a second conductive layer over the entire surface of the substrate to cover the first conductive layer;

forming a first source electrode or drain electrode and a second source electrode or drain electrode by selectively etching the first conductive layer and the second conductive layer so that the first source electrode or drain electrode is electrically connected to the first oxide semiconductor layer, and a part of the second source electrode or drain electrode overlaps with the second gate electrode; and

forming a second oxide semiconductor layer which is electrically connected to the second source electrode or drain electrode in a region which overlaps with the second gate electrode, over the gate insulating layer and the second source electrode or drain electrode.

23. The method for manufacturing a semiconductor device according to claim 21, further comprising the steps of forming, as the first oxide semiconductor layer, an oxide semiconductor layer functioning as a channel formation region of a p-channel transistor;

and forming, as the second oxide semiconductor layer, an oxide semiconductor layer functioning as a channel formation region of an n-channel transistor.

25. The method for manufacturing a semiconductor device according to claim 21, wherein a material which forms a Schottky barrier of 0.5 eV or lower between the material and the first oxide semiconductor layer is included in the first conductive layer, and wherein a material which forms a Schottky barrier of 0.5 eV or lower between the material and the second oxide semiconductor layer is included in the second conductive layer.

27. The method for manufacturing a semiconductor device according to claim 21, wherein a material whose work function is higher than 5.0 eV is included in the first conductive layer, and wherein a material whose work function is lower than 4.8 eV is included in the second conductive layer.

29. The method for manufacturing a semiconductor device according to claim 21, wherein the first, gate electrode and the second gate electrode are formed so as to be electrically connected to each other, and wherein the first source electrode or drain electrode and the second source electrode or drain electrode are formed so as to be electrically connected to each other.

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

forming a first gate electrode and a second gate electrode over a substrate;

forming a gate insulating layer to cover the first gate electrode and the second gate electrode;

forming a first oxide semiconductor layer in a region which overlaps with the first gate electrode, over the gate insulating layer;

forming a first conductive layer over an entire surface of the substrate to cover the first oxide semiconductor layer;

selectively removing the first conductive layer in a region overlapping with the second gate electrode and its periphery;

forming a second conductive layer over the entire surface of the substrate to cover the first conductive layer after selectively removing the first conductive layer;

forming a first source electrode or drain electrode and a second source electrode or drain electrode by selectively etching the first conductive layer and the second conductive layer so that the first source electrode or drain electrode comprises the first conductive layer and the second conductive layer and is electrically connected to the first oxide semiconductor layer, and the second source electrode or drain electrode comprises the second conductive layer and part of which overlaps with the second gate electrode; and

forming a second oxide semiconductor layer which is electrically connected to the second source electrode or drain electrode in a region which overlaps with the second gate electrode, over the gate insulating layer and the second source electrode or drain electrode.

24. The method for manufacturing a semiconductor device according to claim 22, further comprising the steps of forming, as the first oxide semiconductor layer, an oxide semiconductor layer functioning as a channel formation region of a p-channel transistor;

and forming, as the second oxide semiconductor layer, an oxide semiconductor layer functioning as a channel formation region of an n-channel transistor.

26. The method for manufacturing a semiconductor device according to claim 22, wherein a material which forms a Schottky barrier of 0.5 eV or lower between the material and the first oxide semiconductor layer is included in the first conductive layer, and wherein a material which forms a Schottky barrier of 0.5 eV or lower between the material and the second oxide semiconductor layer is included in the second conductive layer.

28. The method for manufacturing a semiconductor device according to claim 22, wherein a material whose work function is higher than 5.0 eV is included in the first conductive layer, and wherein a material whose work function is lower than 4.8 eV is included in the second conductive layer.

30. The method for manufacturing a semiconductor device according to claim 22, wherein the first gate electrode and the second gate electrode are formed so as to be electrically connected to each other, and wherein the first source electrode or drain electrode and the second source electrode or drain electrode are formed so as to be electrically connected to each other.