Semiconductor device and manufacturing method thereof

• US 8,563,976 B2
• Filed: 12/06/2010
• Issued: 10/22/2013
• Est. Priority Date: 12/11/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Akimoto, Kengo
• Primary Examiner(s): Blum, David S
• Application Number:
  US12/960,664
• Publication Number:
  US 20110140109A1
• Time in Patent Office: 1,051 Days
• Field of Search: 257/57, 257/E21.411, 257/E29.296
• 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 29/45 Ohmic electrodes
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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

A semiconductor device includes an oxide semiconductor layer including a channel formation region which includes an oxide semiconductor having a wide band gap and a carrier concentration which is as low as possible, and a source electrode and a drain electrode which include an oxide conductor containing hydrogen and oxygen vacancy, and a barrier layer which prevents diffusion of hydrogen and oxygen between an oxide conductive layer and the oxide semiconductor layer. The oxide conductive layer and the oxide semiconductor layer are electrically connected to each other through the barrier layer.

Claims

1. A semiconductor device comprising:

a first gate electrode over a substrate having a light-transmitting property, the first gate electrode having a light-transmitting property;

a first insulating layer over the first gate electrode, the first insulating layer comprising a first layer and a second layer over the first layer;

a first oxide semiconductor layer over and in contact with the second layer;

a barrier layer over the first oxide semiconductor layer, the barrier layer having a light-transmitting property;

a first electrode over the first oxide semiconductor layer with the barrier layer interposed therebetween, the first electrode overlapping with the first gate electrode;

a second electrode over the first oxide semiconductor layer with the barrier layer interposed therebetween, the second electrode overlapping with the first gate electrode;

a second insulating layer over the first electrode and the second electrode and in contact with a part of the first oxide semiconductor layer; and

a third insulating layer over and in contact with the second insulating layer,

wherein the barrier layer includes a nitride,

wherein a carrier concentration of the first oxide semiconductor layer is lower than 1×

10¹⁴ cm³,

wherein the first electrode and the second electrode each includes an oxide conductor having a light-transmitting property and a resistivity of 2000×

10<sup>−

6</sup> Ω

·

cm or lower, and

wherein the third insulating layer is in contact with a side surface of the second layer and a top surface of the first layer.

2. The semiconductor device according to claim 1, further comprising a gate wiring electrically connected to the first gate electrode, wherein the gate wiring includes a metal.

3. The semiconductor device according to claim 1, further comprising a signal line electrically connected to one of the first electrode and the second electrode through an opening formed in the second insulating layer, wherein the signal line includes a metal.

4. The semiconductor device according to claim 1, further comprising:

a first capacitor electrode over the substrate; and

a second capacitor electrode over the first capacitor electrode with the first insulating layer interposed therebetween,

wherein the first capacitor electrode includes a same material as the first gate electrode, and

wherein the second capacitor electrode includes a same material as the first electrode and the second electrode.

5. The semiconductor device according to claim 1, further comprising:

a gate wiring electrically connected to the first gate electrode; and

a signal line electrically connected to one of the first electrode and the second electrode through an opening formed in the second insulating layer,

wherein the first insulating layer, the second insulating layer, and the first oxide semiconductor layer are sandwiched between the gate wiring and the signal line at an intersection of the gate wiring and the signal line.

6. The semiconductor device according to claim 1, further comprising:

a gate wiring electrically connected to the first gate electrode;

a signal line electrically connected to one of the first electrode and the second electrode through an opening formed in the second insulating layer;

a second gate electrode over the substrate;

a second oxide semiconductor layer over the second gate electrode with the first insulating layer interposed therebetween;

a channel protective layer overlapping with a channel formation region of the second oxide semiconductor layer;

a third electrode overlapping with the channel protective layer; and

a fourth electrode overlapping with the channel protective layer,

wherein the second gate electrode includes a same material as the gate wiring,

wherein the channel protective layer includes a same material as the second insulating layer, and

wherein the third electrode and the fourth electrode each includes a same material as the signal line.

7. The semiconductor device according to claim 1,

wherein the barrier layer comprises a layer selected from a titanium nitride layer, a tantalum nitride layer, a tungsten nitride layer, a molybdenum nitride layer, a silicon nitride layer and an aluminum nitride layer.

8. The semiconductor device according to claim 1,

wherein the first layer and the second layer each comprises a material selected from silicon nitride, silicon oxide, silicon nitride oxide and silicon oxynitride.

9. An electronic appliance comprising the semiconductor device according to claim 1.

10. A semiconductor device comprising:

a first gate electrode over a substrate having a light-transmitting property, the first gate electrode having a light-transmitting property;

a first insulating layer over the first gate electrode, the first insulating layer comprising a first layer and a second layer over the first layer;

a first oxide semiconductor layer over and in contact with the second layer;

a first barrier layer over the first oxide semiconductor layer, the first barrier layer having a light-transmitting property;

a second barrier layer over the first oxide semiconductor layer, the second barrier layer having a light-transmitting property;

a first electrode over the first oxide semiconductor layer with the first barrier layer interposed therebetween, the first electrode overlapping with the first gate electrode;

a second electrode over the first oxide semiconductor layer with the second barrier layer interposed therebetween, the second electrode overlapping with the first gate electrode;

a second insulating layer over the first electrode and the second electrode and in contact with a part of the first oxide semiconductor layer; and

a third insulating layer over and in contact with the second insulating layer,

wherein the first barrier layer and the second barrier layer include a nitride;

wherein a carrier concentration of the first oxide semiconductor layer is lower than 1×

10¹⁴ cm³,

wherein the first electrode and the second electrode each includes an oxide conductor having a light-transmitting property and a resistivity of 2000×

10<sup>−

6</sup> Ω

·

cm or lower, and

wherein the third insulating layer is in contact with a side surface of the second layer and a top surface of the first layer.

11. The semiconductor device according to claim 10, further comprising a gate wiring electrically connected to the first gate electrode, wherein the gate wiring includes a metal.

12. The semiconductor device according to claim 10, further comprising a signal line electrically connected to one of the first electrode and the second electrode through an opening formed in the second insulating layer, wherein the signal line includes a metal.

13. The semiconductor device according to claim 10, further comprising:

a first capacitor electrode over the substrate; and

a second capacitor electrode over the first capacitor electrode with the first insulating layer interposed therebetween,

wherein the first capacitor electrode includes a same material as the first gate electrode, and

wherein the second capacitor electrode includes a same material as the first electrode and the second electrode.

14. The semiconductor device according to claim 10, further comprising:

a gate wiring electrically connected to the first gate electrode; and

a signal line electrically connected to one of the first electrode and the second electrode through an opening formed in the second insulating layer,

wherein the first insulating layer, the second insulating layer, and the first oxide semiconductor layer are sandwiched between the gate wiring and the signal line at an intersection of the gate wiring and the signal line.

15. The semiconductor device according to claim 10, further comprising:

a gate wiring electrically connected to the first gate electrode;

a signal line electrically connected to one of the first electrode and the second electrode through an opening formed in the second insulating layer;

a second gate electrode over the substrate;

a second oxide semiconductor layer over the second gate electrode with the first insulating layer interposed therebetween;

a channel protective layer overlapping with a channel formation region of the second oxide semiconductor layer;

a third electrode overlapping with the channel protective layer; and

a fourth electrode overlapping with the channel protective layer,

wherein the second gate electrode includes a same material as the gate wiring,

wherein the channel protective layer includes a same material as the second insulating layer, and

wherein the third electrode and the fourth electrode each includes a same material as the signal line.

16. The semiconductor device according to claim 10,

wherein the first barrier layer and the second barrier layer each comprises a layer selected from a titanium nitride layer, a tantalum nitride layer, a tungsten nitride layer, a molybdenum nitride layer, a silicon nitride layer and an aluminum nitride layer.

17. The semiconductor device according to claim 10,

wherein the first layer and the second layer each comprises a material selected from silicon nitride, silicon oxide, silicon nitride oxide and silicon oxynitride.

18. An electronic appliance comprising the semiconductor device according to claim 10.