Method of fabricating a thin-film device

Patent metadata

Field	Value
Publication number	US-9209026-B2
Application number	US-201414501286-A
Country	US
Kind code	B2
Filing date	Sep 30, 2014
Priority date	Aug 9, 2006
Publication date	Dec 8, 2015
Grant date	Dec 8, 2015

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.

First claim

What is claimed is:

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

Assignees

• Takechi Kazushige
• Nakata Mitsuru
• Nlt Technologies Ltd

Inventors

• Takechi Kazushige
• Nakata Mitsuru

Classifications

• H10P14/3451

  Structure · CPC title

• H10P14/3426

  Oxides · CPC title

• H10P14/3822 Primary

  Controlling the interface between substrate and epitaxial layer, e.g. by ion implantation followed by annealing · CPC title

• H10D30/6757

  characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715) · CPC title

• H10D99/00

  Subject matter not provided for in other groups of this subclass · CPC title