Oxide semiconductor film and semiconductor device

• US 10,644,164 B2
• Filed: 02/08/2018
• Issued: 05/05/2020
• Est. Priority Date: 04/13/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Takahashi, Masahiro, Akimoto, Kengo, Yamazaki, Shunpei
• Primary Examiner(s): Assouman, Herve-Louis Y
• Application Number:
  US15/891,677
• Publication Number:
  US 20180175207A1
• Time in Patent Office: 817 Days
• Field of Search: None
• CPC Class Codes: C01G 15/006 Compounds containing, besides gallium, indium, or thallium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/123 pixel
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02609 Crystal orientation
• 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 27/1285 using control of the annealing or irradiation parameters, e.g. using different scanning direction or intensity for different transistors
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• 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 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs

Abstract

To provide an oxide semiconductor film having stable electric conductivity and a highly reliable semiconductor device having stable electric characteristics by using the oxide semiconductor film. The oxide semiconductor film contains indium (In), gallium (Ga), and zinc (Zn) and includes a c-axis-aligned crystalline region aligned in the direction parallel to a normal vector of a surface where the oxide semiconductor film is formed. Further, the composition of the c-axis-aligned crystalline region is represented by In_1+δGa_1−δO₃(ZnO)_m (0<δ<1 and m=1 to 3 are satisfied), and the composition of the entire oxide semiconductor film including the c-axis-aligned crystalline region is represented by In_xGa_yO₃(ZnO)_m (0<x<2, 0<y<2, and m=1 to 3 are satisfied).

Claims

1. A semiconductor device comprising:

a substrate;

a source electrode and a drain electrode over the substrate; and

a semiconductor film between the source electrode and the drain electrode, the semiconductor film comprising a first semiconductor film and a second semiconductor film over the first semiconductor film,

wherein a first material of the first semiconductor film has a different composition from a second material of the second semiconductor film,

wherein the second semiconductor film has a higher crystallinity than the first semiconductor film,

wherein each of the first material and the second material is an In—

Ga—

Zn—

O-based metal oxide, and

wherein the first material has a different composition ratio of In to Ga and Zn from the second material.

2. The semiconductor device according to claim 1, further comprising a gate electrode between the substrate and the semiconductor film.

3. The semiconductor device according to claim 1, further comprising a gate electrode over the semiconductor film.

4. The semiconductor device according to claim 1,

wherein a composition of the first material is represented by In_1+δ

Ga<sub>1−

δ</sub>

O₃(ZnO)_m, and

wherein 0<

δ

<

1 and m=1 to 3 are satisfied.

5. The semiconductor device according to claim 1, wherein each of the first material and the second material is represented by In_xGa_yO₃(ZnO)_m where 0<

x<

2, 0<

y<

2, and m=1 to 3 are satisfied.

6. An electronic appliance comprising the semiconductor device according to claim 1, wherein the electronic appliance is any one of a television set, a monitor, a camera, a video camera, a digital photo frame, a mobile phone handset, a game machine, an information terminal, an audio reproducing device and a display device.

7. A semiconductor device comprising:

a substrate;

a source electrode and a drain electrode over the substrate; and

a semiconductor film between the source electrode and the drain electrode, the semiconductor film comprising a first semiconductor film and a second semiconductor film over the first semiconductor film,

wherein a first material of the first semiconductor film has a different composition from a second material of the second semiconductor film,

wherein each of the first semiconductor film and the second semiconductor film comprises crystals,

wherein an alignment of the crystals of the second semiconductor film is higher than an alignment of the crystals of the first semiconductor film,

wherein each of the first material and the second material is an In—

Ga—

Zn—

O-based metal oxide, and

wherein the first material has a different composition ratio of In to Ga and Zn from the second material.

8. The semiconductor device according to claim 7, further comprising a gate electrode between the substrate and the semiconductor film.

9. The semiconductor device according to claim 7, further comprising a gate electrode over the semiconductor film.

10. The semiconductor device according to claim 7,

wherein a composition of the first material is represented by In_1+δ

Ga<sub>1−

δ</sub>

O₃(ZnO)_m, and

wherein 0<

δ

<

1 and m=1 to 3 are satisfied.

11. The semiconductor device according to claim 7, wherein an alignment of c-axes of the crystals of the second semiconductor film is higher than an alignment of each of a-axes and b-axes of the crystals of the second semiconductor film.

12. A semiconductor device comprising:

a substrate; and

a semiconductor film including a channel formation region over the substrate, the semiconductor film comprising a first semiconductor film and a second semiconductor film over the first semiconductor film,

wherein a first material of the first semiconductor film has a different composition from a second material of the second semiconductor film,

wherein the second semiconductor film has a higher crystallinity than the first semiconductor film,

wherein each of the first material and the second material is an In—

Ga—

Zn—

O-based metal oxide, and

wherein the first material has a different composition ratio of In to Ga and Zn from the second material.

13. The semiconductor device according to claim 12, further comprising a gate electrode between the substrate and the semiconductor film.

14. The semiconductor device according to claim 12, further comprising a gate electrode over the semiconductor film.

15. The semiconductor device according to claim 12,

wherein a composition of the first material is represented by In_1+δ

Ga<sub>1−

δ</sub>

O₃(ZnO)_m, and

wherein 0<

δ

<

1 and m=1 to 3 are satisfied.

16. The semiconductor device according to claim 12,

wherein each of the first semiconductor film and the second semiconductor film comprises crystals, and

wherein an alignment of the crystals of the second semiconductor film is higher than an alignment of the crystals of the first semiconductor film.

17. The semiconductor device according to claim 16, wherein an alignment of c-axes of the crystals of the second semiconductor film is higher than an alignment of each of a-axes and b-axes of the crystals of the second semiconductor film.