Semiconductor device

• US 9,614,095 B2
• Filed: 08/07/2012
• Issued: 04/04/2017
• Est. Priority Date: 08/18/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Okazaki, Kenichi, Watanabe, Masahiro, Mashiyama, Mitsuo
• Primary Examiner(s): Gumedzoe, Peniel M
• Assistant Examiner(s): JOHNSON, CHRISTOPHER A
• Application Number:
  US13/568,451
• Publication Number:
  US 20130043465A1
• Time in Patent Office: 1,701 Days
• Field of Search: 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 oxide semiconductor transistor comprising an oxide semiconductor layer with high conductivity is provided. A semiconductor device including an oxide semiconductor layer comprising an oxide containing indium, gallium, and zinc (IGZO) and a particle of indium oxide; a gate electrode overlapping with a channel formation region in the oxide semiconductor layer with a gate insulating film interposed therebetween; and a source electrode and a drain electrode overlapping with a source region and a drain region in the oxide semiconductor layer. The semiconductor device may be a top-gate oxide semiconductor transistor or a bottom-gate oxide semiconductor transistor. The oxide semiconductor layer may be formed over or below the source electrode and the drain electrode.

Claims

1. A semiconductor device comprising:

a gate electrode;

a gate insulating film covering the gate electrode;

an oxide semiconductor layer comprising an oxide containing indium, gallium, and zinc and including a particle of indium oxide represented by In₂O₃, wherein the oxide semiconductor layer overlaps with the gate electrode with the gate insulating film interposed therebetween; and

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

wherein the particle has a wedge shape.

2. The semiconductor device according to claim 1, wherein the oxide semiconductor layer is included in a channel-etch transistor.

3. The semiconductor device according to claim 1, further comprising a substrate and a base insulating film below the gate electrode.

4. The semiconductor device according to claim 1, wherein a tip of the wedge shape is in a direction apart from a top surface of the oxide semiconductor layer.

5. A semiconductor device comprising:

a gate electrode over a substrate;

an oxide semiconductor layer including a channel formation region, a source region, and a drain region, the channel formation region being adjacent to the gate electrode with a gate insulating film interposed therebetween; and

a source electrode and a drain electrode being in contact with the source region and the drain region,

wherein the oxide semiconductor layer comprises an oxide containing indium, gallium, and zinc and includes a particle of indium oxide represented by In₂O₃,

wherein the oxide semiconductor layer includes;

a first portion containing indium, gallium, zinc and oxygen; and

a second portion,

wherein a density of indium in the second portion is lower than a density of indium in the first portion,

wherein a density of oxygen in the second portion is lower than a density of oxygen in the first portion,

wherein the second portion has higher conductivity than other portions of the oxide semiconductor layer, and

wherein the particle has a wedge shape.

6. The semiconductor device according to claim 5, further comprising a base insulating film on the substrate.

7. The semiconductor device according to claim 5, wherein the oxide semiconductor layer covers the gate electrode.

8. The semiconductor device according to claim 5, wherein the source electrode and the drain electrode are provided on the source region and the drain region, respectively.

9. The semiconductor device according to claim 5, wherein a tip of the wedge shape is in a direction apart from a top surface of the oxide semiconductor layer.

10. A semiconductor device comprising:

a gate electrode over a substrate;

an oxide semiconductor layer including a channel formation region, a source region, and a drain region, the channel formation region being adjacent to the gate electrode with a gate insulating film interposed therebetween; and

a source electrode and a drain electrode being in electrical contact with the source region and the drain region,

wherein the oxide semiconductor layer comprises an oxide containing indium, gallium, and zinc and includes a particle of indium oxide,

wherein the oxide semiconductor layer includes;

a first portion containing indium, gallium, zinc and oxygen; and

a second portion,

wherein a density of indium in the second portion is lower than a density of indium in the first portion,

wherein a density of oxygen in the second portion is lower than a density of oxygen in the first portion,

wherein the second portion has higher conductivity than other portions of the oxide semiconductor layer, and

wherein the particle has a wedge shape.

11. The semiconductor device according to claim 10, further comprising a base insulating film on the substrate.

12. The semiconductor device according to claim 10, wherein the oxide semiconductor layer covers the gate electrode.

13. The semiconductor device according to claim 10, wherein the source electrode and the drain electrode are provided on the source region and the drain region, respectively.

14. The semiconductor device according to claim 10, wherein the indium oxide is represented by In₂O₃.

15. The semiconductor device according to claim 10, wherein a tip of the wedge shape is in a direction apart from a top surface of the oxide semiconductor layer.