# US 9,437,745 B2 · Semiconductor device and method for manufacturing same

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- Number: US 9,437,745 B2
- Document ID: US9437745B2
- Status: Granted
- Kind: B2
- Application number: 14/373,620
- Filed: 2013-01-22
- Published: 2014-12-11
- Granted: 2016-09-06
- Earliest claimed: 2012-01-26
- Assignees: Sharp Kabushiki Kaisha
- Applicants: Sharp Kabushiki Kaisha
- Inventors: Yuhichi Saitoh
- Web page: https://patentgrep.com/patent/US9437745B2

## CPC

- H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate}
- H10D 30/6729: {characterised by the electrodes}
- H10D 30/673: {characterised by the shapes, relative sizes or dispositions of the gate electrodes}
- H10D 62/235: {of IGFETs (IGFETs having buried channels H10D30/637)}
- H10D 86/423: {comprising semiconductor materials not belonging to the Group IV, e.g. InGaZnO}
- H10D 86/441: {Interconnections, e.g. scanning lines}
- H10D 86/60: wherein the TFTs are in active matrices
- G02F 1/1368: in which the switching element is a three-electrode device {(G02F1/136277 takes precedence)}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

The present invention provides a semiconductor device which is provided with an oxide semiconductor TFT that can be reduced in the parasitic capacitance by suppressing process damage to a channel, while reducing the channel length (L). A semiconductor device of the present invention is provided with: a gate electrode (3) that is provided on a substrate (1); a first insulating layer (5) that is formed on the gate electrode (3); an island-shaped oxide semiconductor layer (7) that is formed on the first insulating layer (5); a source electrode (11) and a drain electrode (13) that are electrically connected to the oxide semiconductor layer (7); and a protective layer (9) that covers the upper surface of the oxide semiconductor layer (7). The source electrode (11) and/or the drain electrode (13) is arranged on a portion of the side faces of the oxide semiconductor layer (7) and a portion of the side faces of the protective layer (9), but does not cover the upper face of the protective layer (9).

## Claims

### Claim 1

A semiconductor device, comprising:
a substrate;
a gate electrode provided on the substrate;
a first insulating layer formed on the gate electrode;
an island-shaped oxide semiconductor layer formed on the first insulating layer;
a source electrode electrically connected to the oxide semiconductor layer;
a drain electrode electrically connected to the oxide semiconductor layer; and
a protective layer covering an upper face of the oxide semiconductor layer,
wherein at least one of the source electrode and the drain electrode is disposed on a portion of side faces of the oxide semiconductor layer and on a portion of side faces of the protective layer, and does not cover an upper face of the protective layer, and
wherein the side faces of the oxide semiconductor layer include a first side face that has a first taper angle and a second side face that has a second taper angle that is smaller than the first taper angle, and said at least one of the source electrode and the drain electrode is formed on said first side face of the oxide semiconductor layer but is not formed on said second side face, said first taper angle being greater than or equal to 70 degrees and less than 90 degrees and said second taper angle being greater than or equal to 45 degrees and less than 70 degrees.

### Claim 2 (depends on 1)

The semiconductor device according to claim 1, wherein an upper edge face of said at least one of the source electrode and the drain electrode is flush with the upper face of the protective layer.

### Claim 3 (depends on 1)

The semiconductor device according to claim 1, wherein said at least one of the source electrode and the drain electrode is in contact with the oxide semiconductor layer only at the side faces of the oxide semiconductor layer.

### Claim 4 (depends on 1)

The semiconductor device according to claim 1, wherein a portion of the side faces of the oxide semiconductor layer is flush with a portion of the side faces of the protective layer.

### Claim 5 (depends on 1)

The semiconductor device according to claim 1, wherein said oxide semiconductor layer includes an In—Ga—Zn—O semiconductor.