Semiconductor device and method for manufacturing the same

• US 9,252,288 B2
• Filed: 12/24/2013
• Issued: 02/02/2016
• Est. Priority Date: 11/20/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Akimoto, Kengo, Sakata, Junichiro, Hirohashi, Takuya, Takahashi, Masahiro, Kishida, Hideyuki, Miyanaga, Akiharu
• Primary Examiner(s): Smoot, Stephen W
• Assistant Examiner(s): KING, SUN MI KIM
• Application Number:
  US14/140,044
• Publication Number:
  US 20140110709A1
• Time in Patent Office: 770 Days
• Field of Search: 257/43, 257/63, 257/64, 257/E29.296
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/28079 the final conductor layer next to the insulator being a single metal, e.g. Ta, W, Mo, Al
• CPC Class Codes: H01L 21/28158 Making the insulator
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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 29/78693 the semiconducting oxide being amorphous

Abstract

It is an object to provide an oxide semiconductor which is suitable for use in a semiconductor device. Alternatively, it is another object to provide a semiconductor device using the oxide semiconductor. Provided is a semiconductor device including an In—Ga—Zn—O based oxide semiconductor layer in a channel formation region of a transistor. In the semiconductor device, the In—Ga—Zn—O based oxide semiconductor layer has a structure in which crystal grains represented by InGaO₃(ZnO)_m (m=1) are included in an amorphous structure represented by InGaO₃(ZnO)_m (m>0).

Claims

1. A semiconductor device comprising:

a transistor comprising an oxide semiconductor layer,

wherein the oxide semiconductor layer contains In, Ga, and Zn,

wherein the oxide semiconductor layer comprises crystals represented by InGaZnO₄,

wherein a Zn content by atomic percent in the oxide semiconductor layer is less than an In content by atomic percent in the oxide semiconductor layer,

wherein the Zn content by atomic percent in the oxide semiconductor layer is less than a Ga content by atomic percent in the oxide semiconductor layer,

wherein the Ga content by atomic percent in the oxide semiconductor layer is less than the In content by atomic percent in the oxide semiconductor layer, and

wherein a proportion of the crystals represented by InGaZnO₄ to a whole of crystals is 80 volume % or more.

2. The semiconductor device according to claim 1, wherein the oxide semiconductor layer is formed over and in contact with an insulating layer.

3. The semiconductor device according to claim 2, wherein the insulating layer comprises at least one film selected from a silicon oxide film, a silicon oxynitride film, a silicon nitride film, and a silicon nitride oxide film.

4. A semiconductor device comprising:

a transistor comprising an oxide semiconductor layer,

wherein the oxide semiconductor layer comprises a channel formation region,

wherein the channel formation region comprises In, Ga, and Zn,

wherein the channel formation region includes crystals represented by InGaZnO₄,

wherein a Zn content by atomic percent in the oxide semiconductor layer is less than an In content by atomic percent in the oxide semiconductor layer,

wherein the Zn content by atomic percent in the oxide semiconductor layer is less than a Ga content by atomic percent in the oxide semiconductor layer,

wherein the Ga content by atomic percent in the oxide semiconductor layer is less than the In content by atomic percent in the oxide semiconductor layer, and

wherein a proportion of the crystals represented by InGaZnO₄ to a whole of crystals is 80 volume % or more.

5. The semiconductor device according to claim 4, wherein the oxide semiconductor layer is formed over and in contact with an insulating layer.

6. The semiconductor device according to claim 5, wherein the insulating layer comprises at least one film selected from a silicon oxide film, a silicon oxynitride film, a silicon nitride film, and a silicon nitride oxide film.

7. A semiconductor device comprising:

a substrate;

a gate electrode over the substrate;

a gate insulating layer over the gate electrode;

an oxide semiconductor layer; and

a source electrode and a drain electrode in electrical contact with the oxide semiconductor layer,

wherein the oxide semiconductor layer comprises In, Ga, and Zn,

wherein the oxide semiconductor layer includes crystals represented by InGaZnO₄,

wherein a Zn content by atomic percent in the oxide semiconductor layer is less than an In content by atomic percent in the oxide semiconductor layer,

wherein the Zn content by atomic percent in the oxide semiconductor layer is less than a Ga content by atomic percent in the oxide semiconductor layer,

wherein the Ga content by atomic percent in the oxide semiconductor layer is less than the In content by atomic percent in the oxide semiconductor layer, and

wherein a proportion of the crystals represented by InGaZnO₄ to a whole of crystals is 80 volume % or more.

8. The semiconductor device according to claim 7, wherein the gate insulating layer comprises one film or a stack of films selected from a silicon oxide film, a silicon oxynitride film, a silicon nitride film, and a silicon nitride oxide film.

9. The semiconductor device according to claim 7, further comprising a protective insulating layer over and in contact with the oxide semiconductor layer, the source electrode, and the drain electrode.

10. The semiconductor device according to claim 7, wherein the oxide semiconductor layer has a depression.