# US 10,374,097 B2 · Semiconductor device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,374,097 B2
- Document ID: US10374097B2
- Status: Granted
- Kind: B2
- Application number: 15/865,308
- Filed: 2018-01-09
- Published: 2018-05-31
- Granted: 2019-08-06
- Earliest claimed: 2013-12-19
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Shunpei Yamazaki; Akihisa Shimomura; Yuhei Sato; Yasumasa Yamane; Yoshitaka Yamamoto; Hideomi Suzawa; Tetsuhiro Tanaka; Yutaka Okazaki; Naoki Okuno; Takahisa Ishiyama
- Web page: https://patentgrep.com/patent/US10374097B2

## CPC

- H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate}
- H10D 30/6704: {having supplementary regions or layers in the thin films or in the insulated bulk substrates for controlling properties of the device}
- H10D 30/6729: {characterised by the electrodes}
- H10D 30/6757: {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)}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

To provide a transistor having a high on-state current. A semiconductor device includes a first insulator containing excess oxygen, a first oxide semiconductor over the first insulator, a second oxide semiconductor over the first oxide semiconductor, a first conductor and a second conductor which are over the second oxide semiconductor and are separated from each other, a third oxide semiconductor in contact with side surfaces of the first oxide semiconductor, a top surface and side surfaces of the second oxide semiconductor, a top surface of the first conductor, and a top surface of the second conductor, a second insulator over the third oxide semiconductor, and a third conductor facing a top surface and side surfaces of the second oxide semiconductor with the second insulator and the third oxide semiconductor therebetween. The first oxide semiconductor has a higher oxygen-transmitting property than the third oxide semiconductor.

## Claims

### Claim 1

A semiconductor device comprising:
a first insulator;
a first oxide semiconductor film over the first insulator;
a second oxide semiconductor film over the first oxide semiconductor film;
a first conductor and a second conductor over the second oxide semiconductor film;
a third oxide semiconductor film in direct contact with a side surface of the first oxide semiconductor film, a top surface and a side surface of the second oxide semiconductor film, a top surface of the first conductor, and a top surface of the second conductor;
a second insulator over the third oxide semiconductor film; and
a third conductor facing the top surface and the side surface of the second oxide semiconductor film with the second insulator and the third oxide semiconductor film provided therebetween,
wherein the thickness of the first oxide semiconductor film is larger than a thickness of the third oxide semiconductor film, and
wherein any of ends of the third oxide semiconductor film, the second insulator, and the third conductor does not project in a cross-sectional view.

### Claim 2 (depends on 1)

The semiconductor device according to claim 1, wherein the first insulator comprises an oxygen atom which is capable of being released from the first insulator by a heat treatment.

### Claim 3 (depends on 1)

The semiconductor device according to claim 1, further comprising a third insulator covering at least the first insulator, the first oxide semiconductor film, and the second oxide semiconductor film,
wherein the third insulator has a function of blocking oxygen, and
wherein the third insulator has a function of blocking hydrogen.

### Claim 4 (depends on 1)

The semiconductor device according to claim 1,
wherein the first oxide semiconductor film has a lower electron affinity than the second oxide semiconductor film, and
wherein the third oxide semiconductor film has a lower electron affinity than the second oxide semiconductor film.

### Claim 5 (depends on 1)

The semiconductor device according to claim 1,
wherein the first oxide semiconductor film has a larger energy gap than the second oxide semiconductor film, and
wherein the third oxide semiconductor film has a larger energy gap than the second oxide semiconductor film.

### Claim 6 (depends on 1)

The semiconductor device according to claim 1,
wherein the second insulator comprises a region whose hydrogen concentration measured by secondary ion mass spectrometry is lower than 1×1019 atoms/cm3.

### Claim 7 (depends on 1)

The semiconductor device according to claim 1, further comprising:
a third insulator covering at least the first insulator, the first oxide semiconductor film, and the second oxide semiconductor film, and
a fourth insulator over the third insulator,
wherein the fourth insulator comprises a region whose hydrogen concentration measured by secondary ion mass spectrometry is higher than that of a region of the second oxide semiconductor film.

### Claim 8

A semiconductor device comprising:
a first insulator;
a first oxide semiconductor film over the first insulator;
a second oxide semiconductor film over the first oxide semiconductor film;
a first conductor and a second conductor over the second oxide semiconductor film;
a third oxide semiconductor film in direct contact with a side surface of the first oxide semiconductor film, a top surface and a side surface of the second oxide semiconductor film, a top surface of the first conductor, and a top surface of the second conductor;
a second insulator over the third oxide semiconductor film; and
a third conductor facing the top surface and the side surface of the second oxide semiconductor film with the second insulator and the third oxide semiconductor film provided therebetween,
wherein the thickness of the first oxide semiconductor film is larger than a thickness of the third oxide semiconductor film, and
wherein each of the third oxide semiconductor film and the second insulator includes a region not overlapping with the third conductor.

### Claim 9 (depends on 8)

The semiconductor device according to claim 8, wherein the first insulator comprises an oxygen atom which is capable of being released from the first insulator by a heat treatment.

### Claim 10 (depends on 8)

The semiconductor device according to claim 8, further comprising a third insulator covering at least the first insulator, the first oxide semiconductor film, and the second oxide semiconductor film,
wherein the third insulator has a function of blocking oxygen, and
wherein the third insulator has a function of blocking hydrogen.

### Claim 11 (depends on 8)

The semiconductor device according to claim 8,
wherein the first oxide semiconductor film has a lower electron affinity than the second oxide semiconductor film, and
wherein the third oxide semiconductor film has a lower electron affinity than the second oxide semiconductor film.

### Claim 12 (depends on 8)

The semiconductor device according to claim 8,
wherein the first oxide semiconductor film has a larger energy gap than the second oxide semiconductor film, and
wherein the third oxide semiconductor film has a larger energy gap than the second oxide semiconductor film.

### Claim 13 (depends on 8)

The semiconductor device according to claim 8,
wherein the second insulator comprises a region whose hydrogen concentration measured by secondary ion mass spectrometry is lower than 1×1019 atoms/cm3.

### Claim 14 (depends on 8)

The semiconductor device according to claim 8, further comprising:
a third insulator covering at least the first insulator, the first oxide semiconductor film, and the second oxide semiconductor film, and
a fourth insulator over the third insulator,
wherein the fourth insulator comprises a region whose hydrogen concentration measured by secondary ion mass spectrometry is higher than that of a region of the second oxide semiconductor film.