Thin film transistor

Patent metadata

Field	Value
Publication number	US-9202926-B2
Application number	US-201314391104-A
Country	US
Kind code	B2
Filing date	Jun 6, 2013
Priority date	Jun 6, 2012
Publication date	Dec 1, 2015
Grant date	Dec 1, 2015

Abstract

Provided is a thin film transistor having an oxide semiconductor layer that has high mobility, excellent stress resistance, and good wet etching property. The thin film transistor comprises at least, a gate electrode, a gate insulating film, an oxide semiconductor layer, source-drain electrode and a passivation film, in this order on a substrate. The oxide semiconductor layer is a laminate comprising a first oxide semiconductor layer (IGZTO) and a second oxide semiconductor layer (IGZO). The second oxide semiconductor layer is formed on the gate insulating film, and the first oxide semiconductor layer is formed between the second oxide semiconductor layer and the passivation film. The contents of respective metal elements relative to the total amount of all the metal elements other than oxygen in the first oxide semiconductor layer are as follows; In: 25% or less (excluding 0%); Ga: 5% or more; Zn: 30.0 to 60.0%; and Sn: 8 to 30%.

First claim

The invention claimed is:

1. A thin film transistor comprising at least;
a gate electrode, a gate insulating film, an oxide semiconductor layer, a source-drain electrode, and a passivation film to protect the source-drain electrode, on a substrate in this order,
the oxide semiconductor layer is a laminate comprising:
a first oxide semiconductor layer consisting of In, Ga, Zn, Sn, and O; and
a second oxide semiconductor layer consisting of In, Ga, Zn, and O, wherein
the second oxide semiconductor layer is formed on the gate insulating film;
the first oxide semiconductor layer is formed between the second oxide semiconductor layer and the passivation film;
the contents of respective metal elements relative to the total amount of all the metal elements other than oxygen in the first oxide semiconductor layer are;
In: smaller than or equal to 25 atomic % (excluding 0%);
Ga: larger than or equal to 5 atomic %;
Zn: larger than or equal to 30.0 atomic % and smaller than or equal to 60.0 atomic %;
Sn: larger than or equal to 8 atomic % and smaller than or equal to 30 atomic %.

2. The thin film transistor according to claim 1 , wherein the etching rate of the first oxide semiconductor layer to a wet etchant for source-drain electrode is smaller than or equal to one half of etching rate of the source-drain electrode.

3. A thin film transistor comprising at least;
a gate electrode, a gate insulating film, an oxide semiconductor layer, an etch stopper layer, a source-drain electrode, and a passivation film to protect the source-drain electrode, on a substrate in this order,
the oxide semiconductor layer is a laminate comprising:
a first oxide semiconductor layer consisting of In, Ga, Zn, Sn, and O; and a second oxide semiconductor layer consisting of In, Ga, Zn, and O, wherein
the second oxide semiconductor layer is formed on the gate insulating film; the first oxide semiconductor layer is formed between the second oxide semiconductor layer and the etch stopper layer;
the contents of respective metal elements relative to the total amount of all the metal elements other than oxygen in the first oxide semiconductor layer are;
In: smaller than or equal to 25 atomic % (excluding 0%);
Ga: larger than or equal to 8.0 atomic %;
Zn: larger than or equal to 30.0 atomic % and smaller than or equal to 60.0 atomic %;
Sn: larger than or equal to 5 atomic % and smaller than or equal to 35 atomic %.

4. The thin film transistor according to claim 1 , wherein the thickness of the second oxide semiconductor layer is larger than or equal to 0.5 nm.

Assignees

• Kobe Steel Ltd

Inventors

• Kishi Tomoya
• Hirose Kenta
• Morita Shinya
• Kugimiya Toshihiro

Classifications

• H10P14/3434

  being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424) · CPC title

• H10P14/3426 Primary

  Oxides · CPC title

• H10P14/22

  using physical deposition, e.g. vacuum deposition or sputtering · CPC title

• H10D62/875

  being semiconductor metal oxide, e.g. InGaZnO (Group II-VI materials H10D62/86; Group I-VI materials H10D62/871; Pb compounds or alloys H10D62/874) · CPC title

• H10D30/6755 Primary

  Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate · CPC title