Oxide sintered body, sputtering target, and oxide semiconductor thin film obtained using sputtering target

Patent metadata

Field	Value
Publication number	US-2017047206-A1
Application number	US-201515306910-A
Country	US
Kind code	A1
Filing date	May 20, 2015
Priority date	May 23, 2014
Publication date	Feb 16, 2017
Grant date	—

Abstract

Provided are: a sintered oxide which achieves low carrier density and high carrier mobility when configured as an oxide semiconductor thin-film by using the sputtering method; and a sputtering target using the same. This sintered oxide contains indium, gallium and magnesium as oxides. It is preferable for the gallium content to be at least 0.08 and less than 0.20, inclusive, in terms of an atomic ratio (Ga/(In+Ga)), the magnesium content to be at least 0.0001 and less than 0.05 in terms of an atomic ratio (Mg/(In+Ga+Mg)), and the sintering to occur at 1,200-1,550° C., inclusive. An amorphous oxide semiconductor thin-film obtained by forming this sintered oxide as a sputtering target is capable of achieving a carrier density of less than 1.0×10 18 cm −3 , and a carrier mobility of 10 cm 2 V −1 sec −1 or higher.

First claim

1 . An oxide sintered body comprising indium, gallium, and magnesium as oxides, wherein
a gallium content is 0.08 or more and less than 0.20 in terms of Ga/(In+Ga) atomic ratio, a magnesium content is 0.0001 or more and less than 0.05 in terms of Mg/(In+Ga+Mg) atomic ratio, and the oxide sintered body comprises; an In 2 O 3 phase having a bixbyite-type structure; and a GaInO 3 phase having a β-Ga 2 O 3 -type structure as a formed phase other than the In 2 O 3 phase, or a GaInO 3 phase having a β-Ga 2 O 3 -type structure and a (Ga, In) 2 O 3 phase as a formed phase other than the In 2 O 3 phase; and is substantially free of an In(GaMg)O 4 phase, an MgGa 2 O 4 phase, an In 2 MgO 4 phase, and a Ga 2 O 3 phase.

2 . The oxide sintered body according to claim 1 , wherein the magnesium content is 0.01 or more and 0.03 or less in terms of Mg/(In+Ga+Mg) atomic ratio.

3 . The oxide sintered body according to claim 1 , wherein the gallium content is 0.08 or more and 0.15 or less in terms of Ga/(In+Ga) atomic ratio.

4 . The oxide sintered body according to claim 1 , wherein the oxide sintered body is substantially free of positive divalent elements other than magnesium and positive trivalent to positive hexavalent elements other than indium and gallium.

5 . The oxide sintered body according to claim 1 , wherein an X-ray diffraction peak intensity ratio of the GaInO 3 phase having a β-Ga 2 O 3 -type structure defined by formula 1 below is in the range of 2% or more and 45% or less: 100×I [GaInO 3 phase (111)]/{I [In 2 O 3 phase (400)]+I [GaInO 3 phase (111)]}[%] . . . Formula 1 (in Formula 1, I [In 2 O 3 phase (400)] represents a (400) peak intensity of the In 2 O 3 phase having a bixbyite-type structure, and I [GaInO 3 phase (111)] represents a (111) peak intensity of the β-GaInO 3 phase that is a composite oxide having a β-Ga 2 O 3 -type structure.)

6 . A sputtering target obtained by machining the oxide sintered body according to claim 1 .

7 . A crystalline oxide semiconductor thin film obtained by forming an amorphous film on a substrate by sputtering using the sputtering target according to claim 6 and crystallizing the amorphous film by heating in an oxidizing atmosphere.

8 . The oxide semiconductor thin film according to claim 7 , wherein the oxide semiconductor thin film has a carrier mobility of 10 cm 2 V −1 sec −1 or more.

9 . The oxide semiconductor thin film according to claim 7 , wherein the oxide semiconductor thin film has a carrier density of less than 1.0×10 18 cm −3 .

Assignees

• Sumitomo Metal Mining Co

Inventors

• Nakayama Tokuyuki
• Nishimura Eiichiro
• Matsumura Fumihiko
• Iwara Masashi

Classifications

• H10P14/3802

  Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth · CPC title

• H10P14/3454

  Amorphous · CPC title

• H10P14/3438

  Doping during depositing · CPC title

• H10P14/3434

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

• H10P14/2922

  being non-crystalline insulating materials, e.g. glass or polymers · CPC title