Semiconductor device

• US 10,361,318 B2
• Filed: 10/17/2017
• Issued: 07/23/2019
• 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:
  US15/785,562
• Publication Number:
  US 20180053856A1
• Time in Patent Office: 644 Days
• 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 semiconductor device comprising:

an insulating surface;

a first oxide film over and in contact with the insulating surface, the first oxide film comprising indium and gallium;

a second oxide film over and in contact with the first oxide film, the second oxide film comprising indium and gallium; and

a conductive film over and in contact with a top surface of the second oxide film, the conductive film being in contact with a side surface of the first oxide film and a side surface of the second oxide film,

wherein a length of the side surface of the first oxide film is larger than a length of the side surface of the second oxide film in a cross-sectional view, and

wherein the first oxide film is crystalline.

2. The semiconductor device according to claim 1, further comprising a gate electrode under the first oxide film.

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

4. A semiconductor device comprising:

an insulating surface;

a first oxide film over and in contact with the insulating surface, the first oxide film comprising indium, gallium and zinc;

a second oxide film over and in contact with the first oxide film, the second oxide film comprising indium, gallium and zinc; and

a conductive film over and in contact with a top surface of the second oxide film, the conductive film being in contact with a side surface of the first oxide film and a side surface of the second oxide film,

wherein a length of the side surface of the first oxide film is larger than a length of the side surface of the second oxide film in a cross-sectional view.

5. The semiconductor device according to claim 4, further comprising a gate electrode under the first oxide film.

6. The semiconductor device according to claim 4, further comprising a gate electrode over the second oxide film.

7. The semiconductor device according to claim 4, wherein the first oxide film is crystalline.

8. A semiconductor device comprising:

an insulating surface;

a first oxide film over and in contact with the insulating surface, the first oxide film comprising indium;

a second oxide film over and in contact with the first oxide film, the second oxide film comprising indium; and

a conductive film over and in contact with a top surface of the second oxide film, the conductive film being in contact with a side surface of the first oxide film and a side surface of the second oxide film,

wherein a length of the side surface of the first oxide film is larger than a length of the side surface of the second oxide film in a cross-sectional view, and

wherein the first oxide film is crystalline.

9. The semiconductor device according to claim 8, further comprising a gate electrode under the first oxide film.

10. The semiconductor device according to claim 8, further comprising a gate electrode over the second oxide film.