Semiconductor device

• US 10,622,485 B2
• Filed: 04/11/2019
• Issued: 04/14/2020
• Est. Priority Date: 09/29/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Honda, Tatsuya, Tsubuku, Masashi, Nonaka, Yusuke, Shimazu, Takashi, Yamazaki, Shunpei
• Primary Examiner(s): Page, Dale E
• Assistant Examiner(s): Johnson, Christopher A
• Application Number:
  US16/381,479
• Publication Number:
  US 20190237585A1
• Time in Patent Office: 369 Days
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/1337 Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 2202/10 semiconductor
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• 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 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 29/51 Insulating materials associated therewith for MIS structures on thin film semiconductor H01L29/4908
• 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

A semiconductor device includes a gate electrode, a gate insulating film which includes oxidized material containing silicon and covers the gate electrode, an oxide semiconductor film provided to be in contact with the gate insulating film and overlap with at least the gate electrode, and a source electrode and a drain electrode electrically connected to the oxide semiconductor film. In the oxide semiconductor film, a first region which is provided to be in contact with the gate insulating film and have a thickness less than or equal to 5 nm has a silicon concentration lower than or equal to 1.0 at. %, and a region in the oxide semiconductor film other than the first region has lower silicon concentration than the first region. At least the first region includes a crystal portion.

Claims

1. A method for manufacturing a semiconductor device, comprising the steps of:

forming an oxide semiconductor film over a substrate; and

forming a source electrode and a drain electrode over the oxide semiconductor film,

wherein the oxide semiconductor film comprises a first region in which a concentration of carbon is lower than or equal to 1.0×

10¹⁹ atoms/cm³, and

wherein the oxide semiconductor film comprises a second region in which a concentration of carbon is lower than the concentration of carbon in the first region.

2. The method for manufacturing a semiconductor device according to claim 1, further comprising the steps of:

forming a gate electrode;

forming a gate insulating film over the gate electrode,

wherein the gate insulating film comprises an oxide containing silicon, and

wherein the oxide semiconductor film is over the gate insulating film.

3. The method for manufacturing a semiconductor device according to claim 2,

wherein the first region is in contact with the gate insulating film.

4. The method for manufacturing a semiconductor device according to claim 1,

wherein the first region has crystallinity.

5. The method for manufacturing a semiconductor device according to claim 1,

wherein the oxide semiconductor film comprises a crystal portion in which a c-axis is aligned so that an angle between the c-axis and a surface of the oxide semiconductor film is 85°

to 95°

.

6. A method for manufacturing a semiconductor device, comprising the steps of:

forming an oxide semiconductor film over a substrate; and

forming a source electrode and a drain electrode over the oxide semiconductor film,

wherein the oxide semiconductor film comprises a first region in which a concentration of silicon is lower than or equal to 1.0 at. %, and

wherein the oxide semiconductor film comprises a second region in which a concentration of silicon is lower than the concentration of carbon in the first region.

7. The method for manufacturing a semiconductor device according to claim 6, further comprising the steps of:

forming a gate electrode;

forming a gate insulating film over the gate electrode,

wherein the gate insulating film comprises an oxide containing silicon, and

wherein the oxide semiconductor film is over the gate insulating film.

8. The method for manufacturing a semiconductor device according to claim 7,

wherein the first region is in contact with the gate insulating film.

9. The method for manufacturing a semiconductor device according to claim 6,

wherein the first region has crystallinity.

10. The method for manufacturing a semiconductor device according to claim 6,

wherein a concentration of carbon in the first region is lower than or equal to 1.0×

10¹⁹ atoms/cm³.

11. The method for manufacturing a semiconductor device according to claim 6,

wherein the oxide semiconductor film comprises a crystal portion in which a c-axis is aligned so that an angle between the c-axis and a surface of the oxide semiconductor film is 85°

to 95°

.