Method of fabricating a thin-film device

• US 9,209,026 B2
• Filed: 09/30/2014
• Issued: 12/08/2015
• Est. Priority Date: 08/09/2006
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Original Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Inventors: Takechi, Kazushige, Nakata, Mitsuru
• Primary Examiner(s): MENZ, LAURA MARY
• Application Number:
  US14/501,286
• Publication Number:
  US 20150056747A1
• Time in Patent Office: 434 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02587 Structure
• CPC Class Codes: H01L 21/02694 Controlling the interface between substrate and epitaxial layer, e.g. by ion implantation followed by annealing
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• 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 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• 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

A method of forming a thin-film device includes forming an oxide-semiconductor film formed on the first electrical insulator, and forming a second electrical insulator formed on the oxide-semiconductor film, the oxide-semiconductor film defining an active layer. The oxide-semiconductor film is comprised of a first interface layer located at an interface with the first electrical insulator, a second interface layer located at an interface with the second electrical insulator, and a bulk layer other than the first and second interface layers. The method further includes oxidizing the oxide-semiconductor film to render a density of oxygen holes in at least one of the first and second interlayer layers is smaller than a density of oxygen holes in the bulk layer.

Claims

1. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation treatment,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein the thin-film device comprises an insulating substrate; and

the oxide-semiconductor film formed on the first electrical insulator is not in contact with the insulating substrate.

2. The method as set forth in claim 1, wherein said oxidation is comprised of a step of applying plasma to said oxide-semiconductor film in which one of oxygen plasma and ozone plasma is used.

3. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation to said oxide-semiconductor film,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein said first electrical insulator, said oxide-semiconductor film, and said second electrical insulator are formed by forming, in sequence, a gate metal film, a gate insulating film as said first electrical insulator, said oxide-semiconductor film, a source/drain metal film, and a protection insulating film as said second electrical insulator, and

wherein oxidation and the formation of said oxide-semiconductor film are carried out in this order without exposing said oxide-semiconductor film to atmosphere after the formation of said gate insulating film.

4. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation to said oxide-semiconductor film,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein said first electrical insulator, said oxide-semiconductor film, and said second electrical insulator are formed by forming, in sequence, a gate metal film, a gate insulating film as said first electrical insulator, said oxide-semiconductor film, a source/drain metal film, and a protection insulating film as said second electrical insulator, and

wherein reduction to said oxide-semiconductor film and the formation of said source/drain metal film are carried out in this order without exposing said oxide-semiconductor film and said source/drain metal film to atmosphere after said oxide-semiconductor film was patterned.

5. The method as set forth in claim 4, wherein said reduction to said oxide-semiconductor film is comprised of a step of applying plasma to said oxide-semiconductor film in which at least one of rare gas plasma, hydrogen gas plasma, and nitrogen gas plasma alone or in combination is used.

6. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation to said oxide-semiconductor film,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein said first electrical insulator, said oxide-semiconductor film, and said second electrical insulator are formed by forming, in sequence, a gate metal film, a gate insulating film as said first electrical insulator, said oxide-semiconductor film, a source/drain metal film, and a protection insulating film as said second electrical insulator, and

wherein oxidation and the formation of said protection insulating film are carried out in this order without exposing said oxide-semiconductor film and said protection insulating film to atmosphere after said source/drain metal film was patterned.

7. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation to said oxide-semiconductor film,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein said first electrical insulator, said oxide-semiconductor film, and said second electrical insulator are formed by forming, in sequence, an underlying electrically insulating film as said first electrical insulator, a source/drain metal film, said oxide-semiconductor film, a gate insulating film as said second electrical insulator, a gate metal film, and a protection insulating film, and

wherein oxidation and the formation of said gate insulating film are carried out in this order without exposing said oxide-semiconductor film and said gate insulating film to atmosphere after the formation of said oxide-semiconductor film.

8. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation to said oxide-semiconductor film,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein said first electrical insulator, said oxide-semiconductor film, and said second electrical insulator are formed by forming, in sequence, an underlying electrically insulating film as said first electrical insulator, a source/drain metal film, said oxide-semiconductor film, a gate insulating film as said second electrical insulator, a gate metal film, and a protection insulating film, and

wherein oxidation and the formation of said oxide-semiconductor film are carried out in this order without exposing said oxide-semiconductor film to atmosphere after said source/drain metal film was patterned.

9. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation to said oxide-semiconductor film,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein said first electrical insulator, said oxide-semiconductor film, and said second electrical insulator are formed by forming, in sequence, an underlying electrically insulating film as said first electrical insulator, said oxide-semiconductor film, a gate insulating film as said second electrical insulator, a gate metal film, an interlayer insulating film, a source/drain metal film, and a protection insulating film, and

wherein oxidation and the formation of said oxide-semiconductor film are carried out in this order without exposing said oxide-semiconductor film to atmosphere after the formation of said underlying electrically insulating film.

10. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation to said oxide-semiconductor film,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein said first electrical insulator, said oxide-semiconductor film, and said second electrical insulator are formed by forming, in sequence, an underlying electrically insulating film as said first electrical insulator, said oxide-semiconductor film, a gate insulating film as said second electrical insulator, a gate metal film, an interlayer insulating film, a source/drain metal film, and a protection insulating film, and

wherein oxidation and the formation of said gate insulating film are carried out in this order without exposing said oxide-semiconductor film and said gate insulating film to atmosphere after the formation of said oxide-semiconductor film.

11. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation to said oxide-semiconductor film,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein said first electrical insulator, said oxide-semiconductor film, and said second electrical insulator are formed by forming, in sequence, a gate metal film, a gate insulating film as said first electrical insulator, a source/drain metal film, said oxide-semiconductor film, and a protection insulating film as said second electrical insulator, and

wherein oxidation and the formation of said oxide-semiconductor film are carried out in this order without exposing said oxide-semiconductor film to atmosphere after said source/drain metal film was patterned.

12. A method of fabricating a thin-film device, including:

forming an oxide-semiconductor film on a first electrical insulator; and

forming a second electrical insulator on said oxide-semiconductor film,

said oxide-semiconductor film defining an active layer,

said oxide-semiconductor film being formed by repeatedly carrying out formation of an oxide-semiconductor film and oxidation to said oxide-semiconductor film,

said oxide-semiconductor film being comprised of a first interface layer located at an interface with said first electrical insulator, a second interface layer located at an interface with said second electrical insulator, and a bulk layer other than said first and second interface layers,

a density of oxygen holes in at least one of said first and second interface layers being smaller than a density of oxygen holes in said bulk layer,

wherein said first electrical insulator, said oxide-semiconductor film, and said second electrical insulator are formed by forming, in sequence, a gate metal film, a gate insulating film as said first electrical insulator, a source/drain metal film, said oxide-semiconductor film, and a protection insulating film as said second electrical insulator, and

wherein oxidation and the formation of said protection insulating film are carried out in this order without exposing said oxide-semiconductor film and said protection insulating film to atmosphere after said oxide-semiconductor film was patterned.