SWITCHING ELEMENT

• US 20120012838A1
• Filed: 09/23/2011
• Published: 01/19/2012
• Est. Priority Date: 03/12/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.), Japan Science & Technology Trading Co. Limited, Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology)
• Original Assignee: Japan Science & Technology Trading Co. Limited
• Inventors: Hosono, Hideo, Hirano, Masahiro, Ota, Hiromichi, Kamiya, Toshio, Nomura, Kenji
• Granted Patent: US 10,032,931 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: C23C 14/0021 Reactive sputtering or evaporation
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 14/28 by wave energy or particle radiation C23C14/32 - C23C14/48 take precedence
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• 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 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• 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
• 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 switching element of LCDs or organic EL displays which uses a thin film transistor device, includes: a drain electrode, a source electrode, a channel layer contacting the drain electrode and the source electrode, wherein the channel layer comprises indium-gallium-zinc oxide having a transparent, amorphous state of a composition equivalent to InGaO₃(ZnO)_m (wherein m is a natural number less than 6) in a crystallized state, and the channel layer has a semi-insulating property represented by an electron mobility of more than 1 cm²/(V·sec) and an electron carrier concentration is less than 10¹⁸/cm³, a gate electrode, and a gate insulating film positioned between the gate electrode and the channel layer.

Claims

1. A switching element of LCDs or organic EL displays which uses a thin film transistor device comprising:

a drain electrode;

a source electrode;

a channel layer contacting the drain electrode and the source electrode;

wherein the channel layer comprises indium-gallium-zinc oxide having a transparent, amorphous state of a composition equivalent to InGaO₃(ZnO)_m (wherein m is a natural number less than

     6) in a crystallized state, and

the channel layer has a semi-insulating property represented by an electron mobility of more than 1 cm²/(V·

sec) and an electron carrier concentration is less than 10¹⁸/cm³;

a gate electrode; and

a gate insulating film positioned between the gate electrode and the channel layer.

2. The switching element according to claim 1, wherein the gate insulating film contains one or more selected from Al₂O₃, Y₂O₃, or HfO₂.

3. The switching element according to claim 1, wherein the substrate is one of a glass plate, a plastic plate or a plastic film.