Semiconductor device and method for manufacturing the same

• US 9,171,957 B2
• Filed: 01/22/2013
• Issued: 10/27/2015
• Est. Priority Date: 01/26/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Moore, Whitney T
• Assistant Examiner(s): GALVIN III, JOSEPH M
• Application Number:
  US13/746,800
• Publication Number:
  US 20130193432A1
• Time in Patent Office: 1,008 Days
• 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 21/47635 After-treatment of these layers
• CPC Class Codes: H01L 21/477 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/38 - H01L21/449 and H01L21/461 - H01L21/475 take precedence
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14687 Wafer level processing
• 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 29/24 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

Abstract

To provide a highly reliable semiconductor device by giving stable electrical characteristics to a transistor including an oxide semiconductor film. A gate electrode layer is formed over a substrate, a gate insulating film is formed over the gate electrode layer, an oxide semiconductor film is formed over the gate insulating film, a conductive film is formed over the oxide semiconductor film, so that a region in vicinity of an interface with the oxide semiconductor film in contact with the conductive film is made amorphous, heat treatment is performed, the conductive film is then processed to form a source electrode layer and a drain electrode layer, and a part of the amorphous region in the oxide semiconductor film which is exposed by formation of the source electrode layer and the drain electrode layer is removed.

Claims

1. A semiconductor device comprising:

a gate electrode;

a gate insulating film over the gate electrode;

an oxide semiconductor film over the gate insulating film, wherein the oxide semiconductor film comprises a first film in contact with the gate insulating film and a second film over the first film;

a source electrode and a drain electrode over the second film; and

an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode,

wherein, in the oxide semiconductor film, a proportion of a crystal part to an amorphous part in a first region in vicinity of an interface with any of the source electrode and the drain electrode is lower than a proportion of a crystal part to an amorphous part in a second region that is a remaining region of the oxide semiconductor film except the first region,

wherein, in the oxide semiconductor film, a thickness of a third region overlapping with one of the source electrode and the drain electrode and a thickness of a fourth region overlapping with the other of the source electrode and the drain electrode are larger than a thickness of a fifth region overlapping with neither the source electrode nor the drain electrode,

wherein the third region, the fourth region and the fifth region overlap with the gate electrode,

wherein the fifth region is positioned between the third region and the fourth region in a channel length direction,

wherein each of the third region and the fourth region is positioned between parts of the fifth region in a channel width direction, and

wherein the insulating film is in direct contact with a top surface of the first film in the fifth region.

2. The semiconductor device according to claim 1,

wherein hydrogen concentration in the first region is greater than or equal to 5×

10¹⁸/cm³.

3. The semiconductor device according to claim 1,

wherein hydrogen concentration in the second region is less than 5×

10¹⁸/cm³.

4. The semiconductor device according to claim 1,

wherein the crystal part is a c-axis aligned crystalline oxide semiconductor.

5. The semiconductor device according to claim 1,

wherein the oxide semiconductor film comprises a material selected from indium, gallium, zinc, and a combination thereof.

6. The semiconductor device according to claim 1, further comprising:

an oxide insulating film including an oxygen-excess region over the oxide semiconductor film, the source electrode, and the drain electrode; and

an aluminum oxide film over the oxide insulating film.

7. The semiconductor device according to claim 1,

wherein an entire portion of the first region is amorphous.

8. A semiconductor device comprising:

a gate electrode;

a gate insulating film over the gate electrode;

an oxide semiconductor film over the gate insulating film, wherein the oxide semiconductor film comprises a first film in contact with the gate insulating film and a second film over the first film;

a source electrode and a drain electrode over the second film; and

an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode,

wherein, in the oxide semiconductor film, a proportion of a crystal part to an amorphous part in a first region in vicinity of an interface with any of the source electrode and the drain electrode is lower than a proportion of a crystal part to an amorphous part in a second region that is a remaining region of the oxide semiconductor film except the first region,

wherein, in the oxide semiconductor film, a thickness of a third region overlapping with one of the source electrode and the drain electrode and a thickness of a fourth region overlapping with the other of the source electrode and the drain electrode are larger than a thickness of a fifth region overlapping with neither the source electrode nor the drain electrode,

wherein the third region, the fourth region and the fifth region overlap with the gate electrode,

wherein the fifth region is positioned between the third region and the fourth region in a channel length direction,

wherein each of the third region and the fourth region is positioned between parts of the fifth region in a channel width direction,

wherein the insulating film is in direct contact with a top surface of the first film in the fifth region,

wherein the oxide semiconductor film comprises a material selected from indium, gallium, zinc, and a combination thereof, and

wherein the second film has an atomic ratio where an atomic percent of gallium is greater than or equal to an atomic percent of indium.

9. The semiconductor device according to claim 8,

wherein the first film has an atomic ratio where an atomic percent of indium is greater than an atomic percent of gallium.

10. The semiconductor device according to claim 8,

wherein hydrogen concentration in the first region is greater than or equal to 5×

10¹⁸/cm³.

11. The semiconductor device according to claim 8,

wherein hydrogen concentration in the second region is less than 5×

10¹⁸/cm³.

12. The semiconductor device according to claim 8,

wherein the crystal part is a c-axis aligned crystalline oxide semiconductor.

13. The semiconductor device according to claim 8, further comprising:

an oxide insulating film including an oxygen-excess region over the oxide semiconductor film, the source electrode, and the drain electrode; and

an aluminum oxide film over the oxide insulating film.

14. The semiconductor device according to claim 8,

wherein an entire portion of the first region is amorphous.