# US 10,504,924 B2 · Semiconductor device and display device including the semiconductor device

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- Number: US 10,504,924 B2
- Document ID: US10504924B2
- Status: Granted
- Kind: B2
- Application number: 15/583,325
- Filed: 2017-05-01
- Published: 2017-11-09
- Granted: 2019-12-10
- Earliest claimed: 2016-05-09
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Shunpei Yamazaki; Yasutaka Nakazawa; Yasuharu Hosaka; Kenichi Okazaki
- Web page: https://patentgrep.com/patent/US10504924B2

## CPC

- H10D 86/60: wherein the TFTs are in active matrices
- H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate}
- 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 86/423: {comprising semiconductor materials not belonging to the Group IV, e.g. InGaZnO}
- H10D 86/481: {integrated with passive devices, e.g. auxiliary capacitors}
- H10D 30/6734: {having gate electrodes arranged on both top and bottom sides of the channel, e.g. dual-gate TFTs}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

In a transistor including an oxide semiconductor film, field-effect mobility and reliability are improved. A semiconductor device includes a gate electrode, an insulating film over the gate electrode, an oxide semiconductor film over the insulating film, and a pair of electrodes over the oxide semiconductor film. The oxide semiconductor film includes a first oxide semiconductor film and a second oxide semiconductor film over the first oxide semiconductor film. The first oxide semiconductor film is formed using In oxide or In—Zn oxide. The second oxide semiconductor film is formed using In-M-Zn oxide (M is Al, Ga, or Y) and includes a region where the number of In atoms is 40% or more and 50% or less and the number of M atoms is 5% or more and 30% or less of the total number of In, M, and Zn atoms.

## Claims

### Claim 1

A semiconductor device comprising:
a gate electrode;
an insulating film over the gate electrode;
an oxide semiconductor film over the insulating film; and
a pair of electrodes over the oxide semiconductor film,
wherein the oxide semiconductor film comprises a first oxide semiconductor film and a second oxide semiconductor film over the first oxide semiconductor film,
wherein the first oxide semiconductor film is In oxide or In—Zn oxide,
wherein the second oxide semiconductor film is In-M-Zn oxide,
wherein M is Al, Ga, or Y, and
wherein the second oxide semiconductor film comprises a region where a number of the In atoms is greater than or equal to 40% and less than or equal to 50% of a total number of the In atoms, the M atoms, and the Zn atoms, and a region where a number of the M atoms is greater than or equal to 5% and less than or equal to 30% of the total number of the In atoms, the M atoms, and the Zn atoms.

### Claim 2 (depends on 1)

The semiconductor device according to claim 1,
wherein the second oxide semiconductor film comprises a region whose sheet resistance is higher than or equal to 1×102 Ω/square and lower than 1×106 Ω/square in a region in contact with the pair of electrodes.

### Claim 3 (depends on 1)

The semiconductor device according to claim 1,
wherein a peak is observed at around 2θ=31° not in the first oxide semiconductor film but in the second oxide semiconductor film when a crystal structure of the oxide semiconductor film is measured by XRD analysis.

### Claim 4 (depends on 1)

The semiconductor device according to claim 1,
wherein the first oxide semiconductor film comprises a region not comprising the M.

### Claim 5 (depends on 1)

The semiconductor device according to claim 1,
wherein when an atomic ratio of the In to the M to the Zn is x:y:z and x is 4, the second oxide semiconductor film comprises a region where y is higher than or equal to 1.5 and lower than or equal to 2.5 and z is higher than or equal to 2 and lower than or equal to 4.

### Claim 6 (depends on 5)

The semiconductor device according to claim 5,
wherein the atomic ratio of the In to the M to the Zn is 4:2:3 or in a neighborhood of 4:2:3.

### Claim 7 (depends on 1)

The semiconductor device according to claim 1,
wherein when an atomic ratio of the In to the M to the Zn is x:y:z and x is 5, the second oxide semiconductor film comprises a region where y is higher than or equal to 0.5 and lower than or equal to 1.5 and z is higher than or equal to 5 and lower than or equal to 7.

### Claim 8 (depends on 7)

The semiconductor device according to claim 7,
wherein the atomic ratio of the In to the M to the Zn is 5:1:6 or in a neighborhood of 5:1:6.

### Claim 9 (depends on 1)

A display device comprising:
the semiconductor device according to claim 1; and
a display element.

### Claim 10 (depends on 9)

An electronic device comprising:
the display device according to claim 9; and
an operation key or a battery.