AMORPHOUS OXIDE AND THIN FILM TRANSISTOR

• US 20090280600A1
• Filed: 07/16/2009
• Published: 11/12/2009
• Est. Priority Date: 03/12/2004
• Status: Abandoned Application

• Current Assignee: Japan Science And Technology Agency
• Original Assignee: Japan Science And Technology Agency
• Inventors: NOMURA, Kenji, HIRANO, Masahiro, OTA, Hiromichi, HOSONO, Hideo, KAMIYA, Toshio
• Application Number:
  US12/504,158
• Publication Number:
  US 20090280600A1
• Time in Patent Office: Days
• US Class Current: 438/104
• 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

The present invention relates to an amorphous oxide and a thin film transistor using the amorphous oxide. In particular, the present invention provides an amorphous oxide having an electron carrier concentration less than 10¹⁸/cm³, and a thin film transistor using such an amorphous oxide. In a thin film transistor having a source electrode 6, a drain electrode 5, a gate electrode 4, a gate insulating film 3, and a channel layer 2, an amorphous oxide having an electron carrier concentration less than 10¹⁸/cm³ is used in the channel layer 2.

Claims

1. A method of forming a transparent semi-insulating amorphous oxide film, comprising:

depositing a film on a substrate by a vapor-phase growth deposition method using a target of polycrystal of a compound represented by [(Sn<sub>1−

x</sub>M4_x)O₂]a.[In<sub>1−

y</sub>M3_y)₂O₃]_b.[(Zn<sub>1−

z</sub>M2_z)O]_c,

wherein 0≦

x≦

1, 0≦

y≦

1, 0≦

z≦

1;

x, y, and z are not simultaneously 1;

0≦

a≦

1, 0≦

b≦

1, 0≦

c≦

1, and a+b+c=1;

M4 is one or more selected from Si, Ge, and Zr;

M3 is one or more selected form B, Al, Ga, Y and Lu; and

M2 is one or more selected form Mg and Ca,

wherein temperature of the substrate is not intentionally heated, and impurity ions to increase electrical resistance are not intentionally added in the amorphous oxide film, and

atmosphere contains oxygen, oxygen partial pressure being controlled,

electron mobility is 1 cm²/(V·

sec) or more and the electron carrier concentration is 10¹⁶/cm³ or less.

2. The method of forming a transparent semi-insulating amorphous oxide thin film according to claim 1, wherein the substrate is one of a glass plate, a plastic plate or a plastic film.

3. The method of forming a transparent semi-insulating amorphous oxide thin film according to claim 1, wherein the vapor-phase growth deposition method is either a pulse laser deposition method or a sputtering method.

4. The method of forming a transparent semi-insulating amorphous oxide thin film according to claim 1, wherein the compound is In—

Ga—

Zn—

O, the vapor-phase growth deposition method is a pulse laser deposition method and the oxygen partial pressure of over 4.5 Pa.

5. The method of forming a transparent semi-insulating amorphous oxide thin film according to claim 1, wherein the compound is In—

Ga—

Zn—

O, the vapor-phase growth deposition method is a high frequency sputtering method and the oxygen partial pressure of over 3×

10<sup>−

2</sup> Pa.