Sumitomo Metal Mining Company, Ltd.

Eiichiro Nishimura

Tokuyuki Nakayama

Masashi Iwara

Fumihiko Matsumura

Provided are an oxide sintered compact whereby low carrier density and high carrier mobility are obtained when the oxide sintered compact is used to obtain an oxide semiconductor thin film by a sputtering method, and a sputtering target which uses the oxide sintered compact. This oxide sintered compact contains oxides of indium, gallium, and aluminum. The gallium content is from 0.15 to 0.49 by Ga/(In+Ga) atomic ratio, and the aluminum content is from 0.0001 to less than 0.25 by Al/(In+Ga+Al) atomic ratio. A crystalline oxide semiconductor thin film formed using this oxide sintered compact as a sputtering target is obtained at a carrier density of 4.0&#xd7;10cmor less and a carrier mobility of 10 cmVsecor greater.

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

Provided is an oxide sintered body that, when used to obtain an oxide semiconductor thin film by sputtering, can achieve a low carrier concentration and a high carrier mobility. Also provided is a sputtering target using the oxide sintered body. The oxide sintered body contains, as oxides, indium, gallium, and at least one positive divalent element selected from the group consisting of nickel, cobalt, calcium, strontium, and lead. The gallium content, in terms of the atomic ratio Ga/(In+Ga), is from 0.20 to 0.45, and the positive divalent element content, in terms of the atomic ratio M/(In+Ga+M), is from 0.0001 to 0.05. The amorphous oxide semiconductor thin film, which is formed using the oxide sintered body as a sputtering target, can achieve a carrier concentration of less than 3.0&#xd7;10cmand a carrier mobility of at least 10 cmVsec.

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 0.20-0.45, 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&#xb0; 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 3.0&#xd7;10cm, and a carrier mobility of 10 cmVsecor higher.

Provided is a crystalline oxide semiconductor thin film comprising only bixbyite-structured InOphase, suitable as a channel layer material for a thin film transistor, and having excellent etching properties in an amorphous state and a low carrier density and high carrier mobility in a crystalline state. An amorphous oxide thin film is formed using, as a target, an oxide sintered body which comprises indium, gallium, oxygen, and unavoidable impurities, the gallium content being in a range of 0.09 to 0.45 in terms of a Ga/(In+Ga) atomic ratio, has a InOphase having a bixbyite structure as the main crystal phase, and has a GaInOphase having a &#x3b2;-GaO-type structure, or a GaInOphase having a &#x3b2;-GaO-type structure and a (Ga, In)Ophase finely dispersed therein. The amorphous oxide thin film is finely processed by performing etching using photolithography, and is annealed.

Oxide semiconductor thin film and thin film transistor

Provided are: a sintered oxide which is capable of obtaining low carrier density and high carrier mobility when configured as an oxide semiconductor thin film by using a sputtering method; and a sputtering target which uses the same. The sintered oxide contains indium, gallium and copper as oxides. It is preferable for the gallium content to be at least 0.08 and less than 0.20 when expressed as an atomic ratio (Ga/(In+Ga)), the copper content to be at least 0.001 and less than 0.03 when expressed as an atomic ratio (Cu/(In+Ga+Cu)), and for the sintering to be performed at 1,200-1,550&#xb0; C., inclusive. A crystalline oxide semiconductor thin film obtained by forming this sintered oxide as a sputtering target makes it possible to achieve a carrier density of 1.0&#xd7;10cmor lower, and a carrier mobility of 10 cmVsecor higher.

Provided are: a sintered oxide which is capable of obtaining low carrier density and high carrier mobility when configured as an oxide semiconductor thin film by using a sputtering method; and a sputtering target which uses the same. The sintered oxide contains indium, gallium and copper as oxides. It is preferable for the gallium content to be 0.20-0.45, inclusive, when expressed as an atomic ratio (Ga/(In+Ga)), the copper content to be at least 0.001 and less than 0.03 when expressed as an atomic ratio (Cu/(In+Ga+Cu)), and for the sintering to be performed at 1,200-1,550&#xb0; C., inclusive. A crystalline oxide semiconductor thin film obtained by forming this sintered oxide as a sputtering target makes it possible to achieve a carrier density of 3.0&#xd7;10cmor lower, and a carrier mobility of 10 cmVsecor higher.

An oxide sintered body which, when made into an oxide semiconductor thin film by sputtering, can achieve low carrier density and high carrier mobility, and a sputtering target using said oxide sintered body are provided. This oxide sintered body contains indium, gallium and zinc as oxides. The gallium content is 0.20 or more and 0.49 or less in terms of Ga/(In+Ga) atomic ratio, and the zinc content is 0.0001 or more and less than 0.08 in terms of Zn/(In+Ga+Zn) atomic ratio. This amorphous oxide semiconductor thin film is formed with the oxide sintered body as a sputtering target, and can achieve a carrier density of 4.0&#xd7;10cmor less and a carrier mobility of 10 cm/V*s or greater.

An oxide sintered body which, when made into an oxide semiconductor thin film by sputtering, can achieve low carrier density and high carrier mobility, and a sputtering target using said oxide sintered body are provided. This oxide sintered body contains indium, gallium and zinc as oxides. The gallium content is 0.08 or more and less than 0.20 in terms of Ga/(In+Ga) atomic ratio, and the zinc content is 0.0001 or more and less than 0.08 in terms of Zn/(In+Ga+Zn) atomic ratio. This crystalline oxide semiconductor thin film is formed with the oxide sintered body as a sputtering target, and can achieve a carrier density of 8.0&#xd7;10cmor less and a carrier mobility of 10 cm/V&#xb7;s or greater.

The purpose of the present invention is to provide an oxide semiconductor thin film, which has relatively high carrier mobility and is suitable as a channel layer material for a TFT, from an oxynitride crystalline thin film. According to the present invention, a crystalline oxynitride semiconductor thin film is obtained by annealing an amorphous oxynitride semiconductor thin film containing In, O, and N or an amorphous oxynitride semiconductor thin film containing In, O, N, and an additional element M, where M is one or more elements selected from among Zn, Ga, Ti, Si, Ge, Sn, W, Mg, Al, Y and rare earth elements, at a heating temperature of 200&#xb0; C. or more for a heating time of 1 minute to 120 minutes.

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Ome, Japan

Eiichiro Nishimura