# US 9,040,995 B2 · Semiconductor device and method for manufacturing the same

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- Number: US 9,040,995 B2
- Document ID: US9040995B2
- Status: Granted
- Kind: B2
- Application number: 14/221,753
- Filed: 2014-03-21
- Published: 2014-07-24
- Granted: 2015-05-26
- Earliest claimed: 2011-05-05
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Hajime Kimura
- Web page: https://patentgrep.com/patent/US9040995B2

## CPC

- H10D 86/60: wherein the TFTs are in active matrices
- H10D 30/67: Thin-film transistors [TFT] {(Stacked nanowire, nanosheet or nanoribbon FETs H10D30/501)}
- H10D 30/6734: {having gate electrodes arranged on both top and bottom sides of the channel, e.g. dual-gate TFTs}
- H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate}
- H10D 62/405: {Orientations of crystalline planes}
- H10D 86/423: {comprising semiconductor materials not belonging to the Group IV, e.g. InGaZnO}
- H10D 86/451: {characterised by the compositions or shapes of the interlayer dielectrics}
- H10D 86/021: {of multiple TFTs}
- H10D 86/0212: {comprising manufacture, treatment or coating of substrates}
- H10K 59/1213: {the pixel elements being TFTs}
- H10K 59/123: Connection of the pixel electrodes to the thin film transistors [TFT]
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

A semiconductor device includes a pixel electrode and a transistor which includes a first gate electrode, a first insulating layer over the first gate electrode, a semiconductor layer over the first insulating layer, a second insulating layer over the semiconductor layer, and a second gate electrode. The pixel electrode and the second gate electrode are provided over the second insulating layer. The first gate electrode has a region overlapping with the semiconductor layer with the first insulating layer provided therebetween. The second gate electrode has a region overlapping with the semiconductor layer with the second insulating layer provided therebetween. A first region is at least part of a region where the second gate electrode overlaps with the semiconductor layer. A second region is at least part of a region where the pixel electrode is provided. The second insulating layer is thinner in the first region than in the second region.

## Claims

### Claim 1

A semiconductor device comprising:
a first gate electrode;
a first insulating layer over the first gate electrode;
an oxide semiconductor layer over the first insulating layer;
a second insulating layer over the oxide semiconductor layer,
a third insulating layer over the second insulating layer, wherein the third insulating layer is thicker than the second insulating layer;
a second gate electrode in contact with the second insulating layer, the second gate electrode overlapping with the first gate electrode; and
a pixel electrode over the second insulating layer with the third insulating layer interposed therebetween;
a color filter between the second insulating layer and the pixel electrode,
wherein the second gate electrode is separated from the pixel electrode, and
wherein the second gate electrode and the pixel electrode are formed using the same layer.

### Claim 2 (depends on 1)

The semiconductor device according to claim 1,
wherein the oxide semiconductor layer includes a crystal with c-axis alignment.

### Claim 3 (depends on 1)

The semiconductor device according to claim 1, further comprising:
a source electrode and a drain electrode, wherein each of the source electrode and the drain electrode is provided over the oxide semiconductor layer.

### Claim 4 (depends on 3)

The semiconductor device according to claim 3, wherein the pixel electrode is electrically connected to one of the source electrode and the drain electrode through an opening in the second insulating layer.

### Claim 5 (depends on 3)

The semiconductor device according to claim 3, further comprising an insulating layer between the oxide semiconductor layer and each of the source electrode and the drain electrode.

### Claim 6 (depends on 3)

The semiconductor device according to claim 3, wherein the oxide semiconductor layer comprises a region thinner than a region overlapping with the source electrode or the drain electrode.

### Claim 7 (depends on 1)

The semiconductor device according to claim 1, further comprising a capacitor, wherein the pixel electrode functions as one of electrodes of the capacitor.

### Claim 8 (depends on 3)

The semiconductor device according to claim 3, at least one of the source electrode and the drain electrode is in contact with a side surface of the oxide semiconductor layer.

### Claim 9

A semiconductor device comprising:
a transistor including:
a first gate electrode;
a first insulating layer over the first gate electrode;
an oxide semiconductor layer over the first insulating layer;
a second insulating layer over the oxide semiconductor layer, and
a second gate electrode in contact with the second insulating layer,
wherein the first gate electrode overlaps with the oxide semiconductor layer with the first insulating layer provided therebetween, and
wherein the second gate electrode overlaps with the first gate electrode with the oxide semiconductor layer provided therebetween;
a third insulating layer over the second insulating layer, wherein the third insulating layer is thicker than the second insulating layer;
a pixel electrode overlapping with the second insulating layer and the third insulating layer; and
a color filter between the second insulating layer and the pixel electrode,
wherein the second gate electrode overlaps with the oxide semiconductor layer with the second insulating layer interposed therebetween,
wherein the second gate electrode is separated from the pixel electrode, and
wherein the second gate electrode and the pixel electrode are formed using the same layer.

### Claim 10 (depends on 9)

The semiconductor device according to claim 9,
wherein the oxide semiconductor layer includes a crystal with c-axis alignment.

### Claim 11 (depends on 9)

The semiconductor device according to claim 9,
wherein the transistor further includes a source electrode and a drain electrode, and
wherein each of the source electrode and the drain electrode is provided over the oxide semiconductor layer.

### Claim 12 (depends on 9)

The semiconductor device according to claim 9, wherein the pixel electrode is electrically connected to the transistor through an opening in the second insulating layer.

### Claim 13 (depends on 11)

The semiconductor device according to claim 11, further comprising an insulating layer between the oxide semiconductor layer and each of the source electrode and the drain electrode.

### Claim 14 (depends on 11)

The semiconductor device according to claim 11, wherein the oxide semiconductor layer comprises a region thinner than a region overlapping with the source electrode or the drain electrode.

### Claim 15 (depends on 9)

The semiconductor device according to claim 9, further comprising a capacitor, wherein the pixel electrode functions as one of electrodes of the capacitor.

### Claim 16 (depends on 11)

The semiconductor device according to claim 11, at least one of the source electrode and the drain electrode is in contact with a side surface of the oxide semiconductor layer.