Semiconductor device

Patent metadata

Field	Value
Publication number	US-9608124-B2
Application number	US-201514694291-A
Country	US
Kind code	B2
Filing date	Apr 23, 2015
Priority date	Jan 20, 2012
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

Provided is a transistor which has favorable transistor characteristics and includes an oxide semiconductor, and a highly reliable semiconductor device which includes the transistor including the oxide semiconductor. In the semiconductor device including the transistor in which an oxide semiconductor film, a gate insulating film, and a gate electrode are stacked in this order, a sidewall insulating film is formed along side surfaces and a top surface of the gate electrode, and the oxide semiconductor film is subjected to etching treatment so as to have a cross shape having different lengths in the channel length direction or to have a larger length than a source electrode and a drain electrode in the channel width direction. Further, the source electrode and the drain electrode are formed in contact with the oxide semiconductor film.

First claim

What is claimed is:

1. A semiconductor device comprising:
an oxide semiconductor film comprising:
a channel formation region;
a first region protruding from the channel formation region in a first channel width direction; and
a second region protruding from the channel formation region in a second channel width direction opposite to the first channel width direction;

a source electrode in contact with a first side surface of the channel formation region;
a drain electrode in contact with a second side surface of the channel formation region;
a gate electrode overlapping with the first region, the second region, and the channel formation region; and
an insulating film between the oxide semiconductor film and the gate electrode,
wherein the oxide semiconductor film has a cross shape,
wherein the channel formation region is provided between the first region and the second region, and
wherein the channel formation region is provided between the source electrode and the drain electrode in a channel length direction.

2. The semiconductor device according to claim 1 , wherein the gate electrode is over the oxide semiconductor film.

3. The semiconductor device according to claim 1 , wherein the oxide semiconductor film comprises indium, zinc, and a metal element other than indium and zinc.

4. The semiconductor device according to claim 3 , wherein the metal element is gallium.

5. The semiconductor device according to claim 1 ,
wherein the insulating film comprises:
a first insulating film comprising oxygen; and
a second insulating film comprising nitrogen between the first insulating film and the gate electrode.

6. The semiconductor device according to claim 1 , wherein a concentration of copper in the oxide semiconductor film is lower than or equal to 1×10 18 atoms/cm 3 .

7. The semiconductor device according to claim 1 , wherein a concentration of aluminum in the oxide semiconductor film is lower than or equal to 1×10 18 atoms/cm 3 .

8. The semiconductor device according to claim 1 , wherein a concentration of chlorine in the oxide semiconductor film is lower than or equal to 2×10 18 atoms/cm 3 .

9. A semiconductor device comprising:
an oxide semiconductor film comprising:
a channel formation region; and
first and second regions sandwiching the channel formation region in a channel width direction;

source and drain electrodes in contact with side surfaces of the channel formation region;
a gate electrode overlapping with the first and second regions and the channel formation region; and
an insulating film between the oxide semiconductor film and the gate electrode,
wherein the oxide semiconductor film has a cross shape, and
wherein the channel formation region is between the source and drain electrodes in a channel length direction.

10. The semiconductor device according to claim 9 , wherein the gate electrode is over the oxide semiconductor film.

11. The semiconductor device according to claim 9 , wherein the oxide semiconductor film comprises indium, zinc, and a metal element other than indium and zinc.

12. The semiconductor device according to claim 11 , wherein the metal element is gallium.

13. The semiconductor device according to claim 9 ,
wherein the insulating film comprises:
a first insulating film comprising oxygen; and
a second insulating film comprising nitrogen between the first insulating film and the gate electrode.

14. The semiconductor device according to claim 9 , wherein a concentration of copper in the oxide semiconductor film is lower than or equal to 1×10 18 atoms/cm 3 .

15. The semiconductor device according to claim 9 , wherein a concentration of aluminum in the oxide semiconductor film is lower than or equal to 1×10 18 atoms/cm 3 .

16. The semiconductor device according to claim 9 , wherein a concentration of chlorine in the oxide semiconductor film is lower than or equal to 2×10 18 atoms/cm 3 .

Assignees

• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei

Classifications

• H10D30/6729

  characterised by the electrodes · CPC title

• H10D86/60

  wherein the TFTs are in active matrices · 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

• H10D30/6757

  characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715) · CPC title