THIN-FILM TRANSISTOR, METHOD OF FABRICATING THIN-FILM TRANSISTOR, AND DISPLAY DEVICE

• US 20180315858A1
• Filed: 07/06/2018
• Published: 11/01/2018
• Est. Priority Date: 12/03/2014
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: JOLED Inc.
• Inventors: KOBAYASHI, Emi, KANEGAE, Arinobu, FUKUI, Yusuke
• Granted Patent: US 10,644,165 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 29/45 Ohmic electrodes
• 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 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• 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 29/78693 the semiconducting oxide being amorphous

Abstract

A method of fabricating a thin-film transistor is provided. In the method, an oxide semiconductor layer is formed above a substrate. A gate insulating layer is formed above the oxide semiconductor layer. A gate electrode is formed above the gate insulating layer. A metal oxide layer is formed on the oxide semiconductor layer by reactive sputtering to reduce a resistance of the oxide semiconductor layer in a region in contact with the metal oxide layer.

Claims

1. A method of fabricating a thin-film transistor, the method comprising:

forming an oxide semiconductor layer above a substrate;

forming a gate insulating layer above the oxide semiconductor layer;

forming a gate electrode above the gate insulating layer; and

forming a metal oxide layer on the oxide semiconductor layer by reactive sputtering to reduce a resistance of the oxide semiconductor layer in a region in contact with the metal oxide layer.

2. The method according to claim 1, wherein

in the forming of the metal oxide layer, the metal oxide layer is formed by the reactive sputtering using, as a target, a second metal whose bond dissociation energy with oxygen is greater than a bond dissociation energy with oxygen of a first metal included in the oxide semiconductor layer, and

a first concentration ratio of oxygen to the second metal in an interface layer between the metal oxide layer and the oxide semiconductor layer is greater than a second concentration ratio of oxygen to the second metal in a bulk layer of the metal oxide layer.

3. The method according to claim 2, wherein

in the forming of the metal oxide layer, the reactive sputtering is performed while the substrate and the target are offset from one another.

4. A method of fabricating a thin-film transistor, the method comprising:

forming an oxide semiconductor layer above a substrate;

forming a gate insulating layer above the oxide semiconductor layer;

exposing the oxide semiconductor layer and forming a gate electrode above the gate insulating layer; and

forming, by reactive sputtering, a metal oxide layer in direct contact with an exposed portion of the oxide semiconductor layer.

5. The method according to claim 4, wherein

in the forming of the metal oxide layer, the metal oxide layer covers a top surface and a side surface of the gate electrode, a side surface of the gate insulating layer, a top surface of a source region of the oxide semiconductor layer, and a top surface of a drain region of the oxide semiconductor layer.

6. The method according to claim 4, wherein

the metal oxide layer is formed by an oxide of aluminum, titanium, molybdenum, or tungsten.