Semiconductor device and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-10700213-B2
Application number	US-201916353450-A
Country	US
Kind code	B2
Filing date	Mar 14, 2019
Priority date	Mar 6, 2009
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

It is an object to provide a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a semiconductor device including an inverted staggered thin film transistor whose semiconductor layer is an oxide semiconductor layer, a buffer layer is provided over the oxide semiconductor layer. The buffer layer is in contact with a channel formation region of the semiconductor layer and source and drain electrode layers. A film of the buffer layer has resistance distribution. A region provided over the channel formation region of the semiconductor layer has lower electrical conductivity than the channel formation region of the semiconductor layer, and a region in contact with the source and drain electrode layers has higher electrical conductivity than the channel formation region of the semiconductor layer.

First claim

What is claimed is:

1. A semiconductor device comprising:
a gate electrode over a substrate;
a gate insulating layer over the gate electrode;
an oxide semiconductor layer over the gate insulating layer, the oxide semiconductor layer comprising indium, gallium and zinc;
a source electrode electrically connected to the oxide semiconductor layer, the source electrode comprising at least one of titanium, aluminum, manganese, magnesium, zirconium, beryllium, thorium, and copper;
a drain electrode electrically connected to the oxide semiconductor layer, the drain electrode comprising at least one of titanium, aluminum, manganese, magnesium, zirconium, beryllium, thorium, and copper;
a first region between the oxide semiconductor layer and the source electrode; and
a second region between the oxide semiconductor layer and the drain electrode,
wherein a composition ratio of the first region is different from a composition ratio of the oxide semiconductor layer, and
wherein a composition ratio of the second region is different from the composition ratio of the oxide semiconductor layer.

2. The semiconductor device according to claim 1 ,
wherein the oxide semiconductor layer comprises a channel formation region,
wherein a concentration of oxygen in the first region is lower than a concentration of oxygen in the channel formation region, and
wherein a concentration of oxygen in the second region is lower than the concentration of oxygen in the channel formation region.

3. The semiconductor device according to claim 1 , wherein each of the source electrode and the drain electrode overlap with the gate electrode.

4. The semiconductor device according to claim 1 , wherein each of the source electrode and the drain electrode is in contact with the gate insulating layer.

5. The semiconductor device according to claim 1 , further comprising an insulating film over and in contact with the source electrode, the drain electrode, and the oxide semiconductor layer.

6. The semiconductor device according to claim 1 , wherein the oxide semiconductor layer comprises a depressed portion between the source electrode and the drain electrode.

7. The semiconductor device according to claim 1 , wherein each of the first region and the second region comprises a metal oxide.

8. A display module comprising the semiconductor device according to claim 1 , wherein the display module comprises an FPC.

9. An electronic apparatus comprising the semiconductor device according to claim 1 , wherein the electronic apparatus comprises at least one of a speaker, a battery, and an operation key.

10. A semiconductor device comprising:
a gate electrode over a substrate;
a gate insulating layer over the gate electrode;
an oxide semiconductor layer over the gate insulating layer, the oxide semiconductor layer comprising indium, gallium and zinc;
a source electrode electrically connected to the oxide semiconductor layer, the source electrode comprising at least one of titanium, aluminum, manganese, magnesium, zirconium, beryllium, thorium, and copper;
a drain electrode electrically connected to the oxide semiconductor layer, the drain electrode comprising at least one of titanium, aluminum, manganese, magnesium, zirconium, beryllium, thorium, and copper;
a first region between the oxide semiconductor layer and the source electrode; and
a second region between the oxide semiconductor layer and the drain electrode,
wherein a composition ratio of the first region is different from a composition ratio of the oxide semiconductor layer,
wherein a composition ratio of the second region is different from the composition ratio of the oxide semiconductor layer, and
wherein in a channel length direction of the oxide semiconductor layer, the gate electrode comprises a region larger than a length of the oxide semiconductor layer.

11. The semiconductor device according to claim 10 ,
wherein the oxide semiconductor layer comprises a channel formation region,
wherein a concentration of oxygen in the first region is lower than a concentration of oxygen in the channel formation region, and
wherein a concentration of oxygen in the second region is lower than the concentration of oxygen in the channel formation region.

12. The semiconductor device according to claim 10 , wherein each of the source electrode and the drain electrode overlap with the gate electrode.

13. The semiconductor device according to claim 10 , wherein each of the source electrode and the drain electrode is in contact with the gate insulating layer.

14. The semiconductor device according to claim 10 , further comprising an insulating film over and in contact with the source electrode, the drain electrode, and the oxide semiconductor layer.

15. The semiconductor device according to claim 10 , wherein the oxide semiconductor layer comprises a depressed portion between the source electrode and the drain electrode.

16. The semiconductor device according to claim 10 , wherein each of the first region and the second region comprises a metal oxide.

17. A display module comprising the semiconductor device according to claim 10 , wherein the display module comprises an FPC.

18. An electronic apparatus comprising the semiconductor device according to claim 10 , wherein the electronic apparatus comprises at least one of a speaker, a battery, and an operation key.

Assignees

• Semiconductor Energy Lab

Inventors

• Sakata Junichiro
• Hirohashi Takuya
• Kishida Hideyuki

Classifications

• H10P14/3426

  Oxides · CPC title

• H10P14/3434

  being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424) · CPC title

• H10P14/22

  using physical deposition, e.g. vacuum deposition or sputtering · CPC title

• H10D30/6739

  Conductor-insulator-semiconductor electrodes · CPC title

• H10D30/6713

  characterised by the properties of the source or drain regions, e.g. compositions or sectional shapes · CPC title