SEMICONDUCTOR DEVICE AND METHOD FOR PRODUCING SAME

• US 20150041800A1
• Filed: 01/24/2013
• Published: 02/12/2015
• Est. Priority Date: 01/31/2012
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Miyamoto, Tadayoshi, Ito, Kazuatsu, Mori, Shigeyasu, Miyamoto, Mitsunobu, Ogawa, Yasuyuki, Nakazawa, Makoto, Uchida, Seiichi, Matsuo, Takuya
• Granted Patent: US 9,276,126 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/40 Arrangements for improving the aperture ratio
• CPC Class Codes: G02F 2202/10 semiconductor
• 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 27/1259 Multistep manufacturing methods
• CPC Class Codes: H01L 29/45 Ohmic electrodes
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

This semiconductor device (100A) includes: a substrate (1); a gate electrode (3) and a first transparent electrode (2) which are formed on the substrate (1); a first insulating layer (4) formed over the gate electrode (3) and the first transparent electrode (2); an oxide semiconductor layer (5) formed on the first insulating layer (4); source and drain electrodes (6s, 6d) electrically connected to the oxide semiconductor layer (5); and a second transparent electrode (7) electrically connected to the drain electrode (6d). At least a portion of the first transparent electrode (2) overlaps with the second transparent electrode (7) with the first insulating layer (4) interposed between them, and the oxide semiconductor layer (5) and the second transparent electrode (7) are formed out of the same oxide film.

Claims

1. A semiconductor device comprising:

a substrate;

a gate electrode and a first transparent electrode which are formed on the substrate;

a first insulating layer formed over the gate electrode and the first transparent electrode;

an oxide semiconductor layer formed on the first insulating layer;

source and drain electrodes electrically connected to the oxide semiconductor layer; and

a second transparent electrode electrically connected to the drain electrode,

wherein at least a portion of the oxide semiconductor layer overlaps with the gate electrode with the first insulating layer interposed between them, at least a portion of the first transparent electrode overlaps with the second transparent electrode with the first insulating layer interposed between them, and the oxide semiconductor layer and the second transparent electrode are formed out of the same oxide film.

2. The semiconductor device of claim 1, wherein the drain electrode is formed on the second transparent electrode, and

the second transparent electrode contacts directly with the drain electrode.

3. The semiconductor device of claim 1 or 2, wherein the second transparent electrode contains an impurity at a higher concentration than the oxide semiconductor layer.

4. The semiconductor device of claim 1, further comprising a second insulating layer formed between the gate electrode and the substrate,

wherein the second insulating layer is formed over the first transparent electrode.

5. The semiconductor device of claim 1, further comprising a second insulating layer formed over the gate electrode,

wherein the first transparent electrode is formed on the second insulating layer.

6. The semiconductor device of claim 1, further comprising an insulating protective layer formed over the source and drain electrodes,

wherein the insulating protective layer is formed to contact with a channel region of the oxide semiconductor layer, and

the insulating protective layer is made of an oxide.

7. The semiconductor device of claim 1, wherein the first insulating layer includes an oxide insulating layer, and

the oxide insulating layer contacts with the oxide semiconductor layer.

8. The semiconductor device of claim 1, wherein the oxide film includes In, Ga and Zn.

15. The semiconductor device of claim 1, wherein the oxide semiconductor layer includes an In—

Ga—

Zn—

O based semiconductor.

9. A method for fabricating a semiconductor device, the method comprising the steps of:

(a) providing a substrate;

(b) forming a gate electrode and a first transparent electrode on the substrate;

(c) forming a first insulating layer over the gate electrode and the first transparent electrode;

(d) forming an oxide semiconductor film over the first insulating layer;

(e) forming source and drain electrodes on the oxide semiconductor film; and

(f) performing a resistance lowering process to lower the resistance of a portion of the oxide semiconductor film, thereby forming a second transparent electrode and turning the rest of the oxide semiconductor film, of which the resistance has not been lowered, into an oxide semiconductor layer, whereby at least a portion of the oxide semiconductor layer overlaps with the gate electrode with the first insulating layer interposed between them, and at least a portion of the second transparent electrode overlaps with the first transparent electrode with the first insulating layer interposed between them.

10. The method of claim 9, wherein the step (f) includes implanting an impurity into the portion of the oxide semiconductor film.

11. The method of claim 9 or 10, wherein the step (b) includes forming the first transparent electrode on the substrate, forming a second insulating layer over the first transparent electrode, and then forming the gate electrode on the second insulating layer.

12. The method of claim 9 or 10, wherein the step (b) includes forming the gate electrode on the substrate, forming a second insulating layer over the gate electrode, and then forming the first transparent electrode on the second insulating layer.

13. The method of claim 9, wherein the step (f) includes the step (f2) of forming a protective layer to protect the channel region of the oxide semiconductor film before performing the resistance lowering process.

14. The method of claim 13, wherein when viewed along a normal to the substrate, an end portion of the protective layer overlaps with the drain electrode.

16. The method of claim 9, wherein the oxide semiconductor film includes an In—

Ga—

Zn—

O based semiconductor.