SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SEMICONDUCTOR DEVICE

• US 20110084270A1
• Filed: 10/06/2010
• Published: 04/14/2011
• Est. Priority Date: 10/09/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei
• Granted Patent: US 9,209,310 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• 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 a thin film transistor including an oxide semiconductor layer, in which a material used for the oxide semiconductor layer and a material used for source and drain electrode layers are prevented from reacting with each other. The source and drain electrode layers provided over a substrate having an insulating surface have a stacked structure of two or more layers. In the stack of layers, a layer which is in contact with an oxide semiconductor layer is a metal layer including a metal element other than a metal element included in the oxide semiconductor layer. An element selected from Sn, Sb, Se, Te, Pd, Ag, Ni, and Cu; an alloy containing any of these elements as a component; an alloy containing any of these elements in combination; or the like is used for a material of the metal layer used.

Claims

1. A semiconductor device comprising:

a substrate having an insulating surface;

a gate electrode layer over the substrate having the insulating surface;

a gate insulating layer over the gate electrode layer;

an oxide semiconductor layer over the gate insulating layer; and

a source electrode layer and a drain electrode layer over the oxide semiconductor layer,

wherein the source electrode layer and the drain electrode layer are formed with a stack of layers,

wherein a first metal layer included in the stack of layers is in contact with the oxide semiconductor layer, and

wherein the first metal layer is formed using a metal layer of a metal element selected from Sn, Sb, Se, Te, Pd, Ag, Ni, and Cu, an alloy containing any of these elements as a component, or an alloy containing any of these elements in combination.

2. The semiconductor device according to claim 1, wherein the metal element included in the first metal layer is different from a metal element included in the oxide semiconductor layer.

3. The semiconductor device according to claim 1, further comprising a second metal layer formed on and in contact with the first metal layer in the stack of layers,

wherein the metal element included in the first metal layer is different from a metal element included in the second metal layer of the stack of layers.

4. The semiconductor device according to claim 3, wherein the second metal layer of the stack of layers is formed using a metal layer of an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, an alloy containing any of these elements as a component, or an alloy containing any of these elements in combination.

5. The semiconductor device according to claim 1, further comprising a first molybdenum layer, and an aluminum layer, and a second molybdenum layer sequentially stacked over the first metal layer,

wherein the first molybdenum layer is on and in contact with the first metal layer.

6. A semiconductor device comprising:

a substrate having an insulating surface;

a gate electrode layer over the substrate having the insulating surface;

a gate insulating layer over the gate electrode layer;

an oxide semiconductor layer over the gate insulating layer; and

a source electrode layer and a drain electrode layer over the oxide semiconductor layer,

wherein the source electrode layer and the drain electrode layer are formed with a stack of layers, and

wherein a first metal layer included in the stack of layers is in contact with the oxide semiconductor layer, and

wherein the first metal layer is formed using a metal layer of Au or Pt.

7. The semiconductor device according to claim 6, wherein the metal element included in the first metal layer is different from a metal element included in the oxide semiconductor layer.

8. The semiconductor device according to claim 6, further comprising a second metal layer formed on and in contact with the first metal layer in the stack of layers,

wherein the metal element included in the first metal layer is different from a metal element included in the second metal layer of the stack of layers.

9. The semiconductor device according to claim 8, wherein the second metal layer of the stack of layers is formed using a metal layer of an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, an alloy containing any of these elements as a component, or an alloy containing any of these elements in combination.

10. The semiconductor device according to claim 6, further comprising a first molybdenum layer, and an aluminum layer, and a second molybdenum layer sequentially stacked over the first metal layer,

wherein the first molybdenum layer is on and in contact with the first metal layer.

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

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming an oxide semiconductor layer over the gate insulating layer;

forming a stack of a first metal layer and a second metal layer over the oxide semiconductor layer; and

selectively etching the stack of the first metal layer and the second metal layer, so that a source electrode layer and a drain electrode layer having the stack are formed;

wherein a metal element included in the first metal layer is at least one selected from Sn, Sb, Se, Te, Pd, Ag, Ni, Cu, Pt, and Au,

wherein the first metal layer is in contact with the oxide semiconductor layer, and

wherein the metal element included in the first metal layer is other than a metal element included in the oxide semiconductor layer.

12. The method for manufacturing the semiconductor device according to claim 11, wherein the metal element included in the first metal layer is different from a metal element included in the second metal layer.

13. The method for manufacturing the semiconductor device according to claim 12, wherein the metal element included in the second metal layer is at least one selected from Al, Cr, Cu, Ta, Ti, Mo, and W.

14. The method for manufacturing the semiconductor device according to claim 11,

wherein the second metal layer comprises a first molybdenum layer, an aluminum layer, and a second molybdenum layer sequentially stacked over the first metal layer,

wherein the first molybdenum layer is on and in contact with the first metal layer.

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

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming a stack of a first metal layer and a second metal layer over the gate insulating layer;

selectively etching the stack of the first metal layer and the second metal layer, so that a source electrode layer and a drain electrode layer having the stack are formed; and

forming an oxide semiconductor layer over the source electrode layer and the drain electrode layer,

wherein a metal element included in the second metal layer is at least one selected from Sn, Sb, Se, Te, Pd, Ag, Ni, Cu, Pt, and Au,

wherein the second metal layer is in contact with the oxide semiconductor layer, and

wherein the metal element included in the second metal layer is other than a metal element included in the oxide semiconductor layer.

16. The method for manufacturing the semiconductor device according to claim 15, wherein the metal element included in the second metal layer is different from a metal element included in the first metal layer.

17. The method for manufacturing the semiconductor device according to claim 16, wherein the metal element included in the second metal layer is at least one selected from Al, Cr, Cu, Ta, Ti, Mo, and W.

18. The method for manufacturing the semiconductor device according to claim 15,

wherein the second metal layer comprises a first molybdenum layer, an aluminum layer, and a second molybdenum layer sequentially stacked over the first metal layer,

wherein the first molybdenum layer is on and in contact with the first metal layer.