Oxide semiconductor, thin film transistor array substrate and production method thereof, and display device

• US 8,865,516 B2
• Filed: 03/10/2010
• Issued: 10/21/2014
• Est. Priority Date: 06/29/2009
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ohta, Yoshifumi, Mori, Go, Nishiki, Hirohiko, Chikama, Yoshimasa, Aita, Tetsuya, Suzuki, Masahiko, Nakagawa, Okifumi, Takei, Michiko, Harumoto, Yoshiyuki, Hara, Takeshi
• Primary Examiner(s): Luu, Chuong A
• Assistant Examiner(s): ESKRIDGE, CORY W
• Application Number:
  US13/377,824
• Publication Number:
  US 20120091452A1
• Time in Patent Office: 1,686 Days
• Field of Search: 438/104, 438/FOR.184, 438/FOR.201, 438/149, 257/43, 257/E29.296, 257/E21.46, 257/E29.151, 257/E51.005
• US Class Current: 438/104
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2202/10 semiconductor
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 29/22 including, apart from doping materials or other impurities, only AIIBVI compounds
• CPC Class Codes: H01L 29/45 Ohmic electrodes
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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

Abstract

The present invention provides an oxide semiconductor capable of achieving a thin film transistor having stable transistor characteristics, a thin film transistor having a channel layer formed of the oxide semiconductor and a production method thereof, and a display device equipped with the thin film transistor. The oxide semiconductor of the present invention is an oxide semiconductor for a thin film transistor. The oxide semiconductor includes indium, gallium, zinc, and oxygen as constituent atoms, and the oxygen content of the oxide semiconductor is 87% to 95% of the stoichiometric condition set as 100%, in terms of atomic units.

Claims

1. A method of producing a thin film transistor array substrate including a substrate and a thin film transistor mounted on a main surface of the substrate, the method comprising the steps of

forming an insulating film covering a scanning wiring formed on a main surface of the substrate,

forming a semiconductor layer to form an oxide semiconductor layer at a position overlapping the scanning wiring upon seeing a substrate surface from a normal direction,

forming a wiring and an electrode to form a signal wiring and a drain electrode on the oxide semiconductor layer,

forming a protective layer contacting the oxide semiconductor layer and covering the signal wiring and the drain electrode, the protective layer including a material containing an oxygen atom, and

forming an interlayer insulating film covering the protective layer,

wherein a baking treatment is further included between the step of forming the protective layer and the step of forming the interlayer insulating film, and

oxygen is supplied to the oxide semiconductor layer from the protective layer in the baking treatment.

2. The method of producing a thin film transistor array substrate according to claim 1,

wherein the baking treatment is performed at a highest treatment temperature among all treatment temperatures in the production steps of the thin film transistor array substrate.

3. The method of producing a thin film transistor array substrate according to claim 1,

wherein the baking treatment is performed at a temperature higher than a temperature in forming the protective layer and forming the interlayer insulating film.

4. The method of producing a thin film transistor array substrate according to claim 1,

wherein the baking treatment causes an oxygen content of the oxide semiconductor layer to be 87% to 95% in accordance with the following formula:

O(atomic %)/{In(atomic %)×

3/2+Ga(atomic %)×

3/2+Zn(atomic %)}.