Semiconductor device

• US 9,449,819 B2
• Filed: 10/08/2015
• Issued: 09/20/2016
• Est. Priority Date: 11/16/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Sato, Takahiro, Nakazawa, Yasutaka, Cho, Takayuki, Koshioka, Shunsuke, Tokunaga, Hajime, Jintyou, Masami
• Primary Examiner(s): Rodela, Eduardo A
• Application Number:
  US14/878,399
• Publication Number:
  US 20160035567A1
• Time in Patent Office: 348 Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 21/02365 Forming inorganic semiconducting materials on a substrate for light-sensitive devices H01L31/00
• CPC Class Codes: H01L 21/02403 Oxides
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02551 Group 12/16 materials
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 21/30604 Chemical etching
• CPC Class Codes: H01L 21/465 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/469
• 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 27/1259 Multistep manufacturing methods
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/0657 characterised by the shape of the body
• CPC Class Codes: H01L 29/1033 with insulated gate, e.g. characterised by the length, the width, the geometric contour or the doping structure with channel and gate aligned in the lengthwise direction H01L29/42376; with buried channel H01L29/7838
• 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 29/42356 Disposition, e.g. buried gate electrode H01L29/42324 and H01L29/4234 take precedence
• 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 29/786 : Thin film transistors, i.e. transistors with a channel being at least partly a thin film transistors having only the source or the drain region on an insulator layer H01L29/0653; thin film FinFETs H01L29/785
• CPC Class Codes: H01L 29/78603 : characterised by the insulating substrate or support H01L29/78657 takes precedence
• 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
• 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 59/123 : Connection of the pixel electrodes to the thin film transistors [TFT]

Abstract

A transistor includes a multilayer film in which an oxide semiconductor film and an oxide film are stacked, a gate electrode, and a gate insulating film. The multilayer film overlaps with the gate electrode with the gate insulating film interposed therebetween. The multilayer film has a shape having a first angle between a bottom surface of the oxide semiconductor film and a side surface of the oxide semiconductor film and a second angle between a bottom surface of the oxide film and a side surface of the oxide film. The first angle is acute and smaller than the second angle. Further, a semiconductor device including such a transistor is manufactured.

Claims

1. A method for manufacturing an oxide semiconductor film and an oxide film, comprising:

forming an oxide semiconductor film;

forming an oxide film over the oxide semiconductor film; and

etching the oxide semiconductor film and the oxide film by an etchant comprising a phosphoric acid,

wherein each of the oxide film and the oxide semiconductor film comprises an In-M-Zn oxide (M is one selected from the group consisting of Al, Ga, Ge, Y, Zr, Sn, La, Ce, and Nd), and the oxide film has a lower atomic ratio of In to M than the oxide semiconductor film.

2. The method for manufacturing an oxide semiconductor film and an oxide film, according to claim 1, wherein the etchant comprising the phosphoric acid is a phosphoric acid solution.

3. The method for manufacturing an oxide semiconductor film and an oxide film, according to claim 1,

wherein the In-M-Zn oxide comprised in the oxide film is an In—

Ga—

Zn oxide, and

wherein the In-M-Zn oxide comprised in and the oxide semiconductor film is an In—

Ga—

Zn oxide.

4. The method for manufacturing an oxide semiconductor film and an oxide film, according to claim 1,

wherein the oxide semiconductor film comprises a crystal part, and

wherein a c-axis of the crystal part is parallel to a normal vector of a surface of the oxide semiconductor film.

5. A method for manufacturing an oxide semiconductor film and an oxide film, comprising:

forming a first oxide semiconductor film;

forming a first oxide film over the first oxide semiconductor film; and

etching the first oxide semiconductor film and the first oxide film by an etchant comprising a phosphoric acid so as to form a second oxide semiconductor film and a second oxide film over the second oxide semiconductor film,

wherein each of the first oxide film and the first oxide semiconductor film comprises an In-M-Zn oxide (M is one selected from the group consisting of Al, Ga, Ge, Y, Zr, Sn, La, Ce, and Nd), and the first oxide film has a lower atomic ratio of In to M than the first oxide semiconductor film,

wherein the second oxide semiconductor film has a first angle formed between a bottom surface of the second oxide semiconductor film and a side surface of the second oxide semiconductor film, and

wherein the second oxide film has a second angle formed between a bottom surface of the second oxide film and a side surface of the second oxide film, the second angle being greater than the first angle and being greater than or equal to 10° and

less than 90°

.

6. The method for manufacturing an oxide semiconductor film and an oxide film, according to claim 5, wherein the etchant comprising the phosphoric acid is a phosphoric acid solution.

7. The method for manufacturing an oxide semiconductor film and an oxide film, according to claim 5,

wherein the In-M-Zn oxide comprised in the second oxide film is an In—

Ga—

Zn oxide, and

wherein the In-M-Zn oxide comprised in and the second oxide semiconductor film is an In—

Ga—

Zn oxide.

8. The method for manufacturing an oxide semiconductor film and an oxide film, according to claim 5, wherein the first angle of the second oxide semiconductor film is greater than or equal to 10°

and less than 90°

.

9. The method for manufacturing an oxide semiconductor film and an oxide film, according to claim 5,

wherein the second oxide semiconductor film comprises a crystal part, and

wherein a c-axis of the crystal part is parallel to a normal vector of a surface of the oxide semiconductor film.

10. A method for manufacturing a semiconductor device, comprising:

forming a transistor comprising the second oxide semiconductor film and the second oxide film manufactured by the method according to claim 5,

wherein the second oxide semiconductor film comprises a channel formation region.

11. A method for manufacturing a semiconductor device, comprising:

forming a transistor, the transistor comprising;

an oxide semiconductor film comprising a channel formation region;

an oxide film over the oxide semiconductor film; and

a conductive film over the oxide semiconductor film and the oxide film, the conductive film being in contact with a side surface of the oxide semiconductor film and a side surface of the oxide film,

forming an insulating film over the oxide semiconductor film, the oxide film, and the conductive film, and

forming an electrode over the insulating film, the electrode being electrically connected to the oxide semiconductor film through the conductive film,

wherein each of the oxide film and the oxide semiconductor film comprises an In-M-Zn oxide (M is one selected from the group consisting of Al, Ga, Ge, Y, Zr, Sn, La, Ce, and Nd), and the oxide film has a lower atomic ratio of In to M than the oxide semiconductor film,

wherein the oxide semiconductor film has a first angle formed between a bottom surface of the oxide semiconductor film and a side surface of the oxide semiconductor film, and

wherein the oxide film has a second angle formed between a bottom surface of the oxide film and a side surface of the oxide film, the second angle being greater than the first angle and being greater than or equal to 10° and

less than 90°

.

12. The method for manufacturing a semiconductor device, according to claim 11, wherein the transistor comprises a gate electrode under the oxide semiconductor film.

13. The method for manufacturing a semiconductor device, according to claim 11,

wherein the In-M-Zn oxide comprised in the oxide film is an In—

Ga—

Zn oxide, and

wherein the In-M-Zn oxide comprised in and the oxide semiconductor film is an In—

Ga—

Zn oxide.

14. The method for manufacturing a semiconductor device, according to claim 11, wherein the first angle of the oxide semiconductor film is greater than or equal to 10°

and less than 90°

.

15. The method for manufacturing a semiconductor device, according to claim 11,

wherein the oxide semiconductor film comprises a crystal part, and

wherein a c-axis of the crystal part is parallel to a normal vector of a surface of the oxide semiconductor film.

16. The method for manufacturing a semiconductor device, according to claim 11, further comprising:

forming a liquid crystal layer over the electrode.

17. The method for manufacturing a semiconductor device, according to claim 11, further comprising:

forming a light-emitting layer over the electrode.