JP5403464B2 - Thin film device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a thin film device and a manufacturing method thereof.

  Oxide transparent conductive films such as ITO film, which is a compound of indium, tin, and oxygen, have a sheet resistance of several ohms / square in a thin film of about several hundred nm and high transmittance for visible light. Therefore, it is widely used for various flat panel displays, photoelectric conversion elements and the like.

  In recent years, research on thin film transistors using an oxide transparent semiconductor film such as In—Ga—Zn—O as a channel layer has been started. Such an oxide semiconductor is formed of a bond with high ionicity, and is characterized by a small difference in electron mobility between crystal and amorphous. Accordingly, relatively high electron mobility is obtained even in an amorphous state. Since an amorphous film can be formed at room temperature by using a sputtering method or the like, research on forming an oxide semiconductor thin film transistor on a resin substrate such as PET has been started.

  As a prior art document regarding a thin film transistor provided with an oxide semiconductor, for example, there are Patent Documents 1-5.

  In Patent Documents 1-5, the material composition of the semiconductor film and the insulating film is described in detail, and the material composition for realizing good transistor electrical characteristics is defined.

Japanese Patent Laying-Open No. 2005-033172 (paragraph number 0041) JP 2003-179233 A (paragraph numbers 0014 to 0016) JP 2003-86808 A (paragraph number 0053) JP 2003-60170 A (paragraph number 0037) JP-T-2006-502597 (paragraph numbers 0021 to 0023)

  However, in a thin film transistor using an oxide semiconductor, donor defects caused by oxygen vacancies in an interface layer between a semiconductor film, in particular, a semiconductor film and an insulating film greatly affect the electrical characteristics. In this technique, the control of oxygen vacancies in the interface layer was insufficient. In particular, Patent Document 5 states that oxygen vacancies can be reduced by annealing an oxide semiconductor in an oxidizing atmosphere at a temperature of 300 ° C. or higher. Such an annealing treatment may be effective in reducing oxygen vacancies on the upper surface of the oxide semiconductor film, but the lower surface of the oxide semiconductor (that is, the base insulator and the oxide semiconductor formed thereon) This is not effective in reducing oxygen vacancies in the oxide semiconductor region in the vicinity of the interface. This is because such a thermal oxidation treatment hardly penetrates into the membrane. Of course, by raising the temperature to about 600 ° C. or higher, the osmosis effect of oxidation may be improved and the lower surface of the oxide semiconductor film may be oxidized. However, in this case, an inexpensive glass substrate cannot be used as the insulating substrate. However, when a metal film is present in a layer below the oxide semiconductor, there still remains a problem that contamination such as diffusion of the metal into the semiconductor film is caused by this high temperature treatment.

  Therefore, an oxide semiconductor thin film transistor having good characteristics that can be used as a display drive element cannot be manufactured on an inexpensive glass substrate with good reproducibility and yield.

  The present invention has been made to solve the above-described problems, and can control the generation of oxygen vacancies in the interface layer, and can reproduce thin film transistors or other thin film devices having good characteristics. -It aims at providing the thin film device which can be manufactured with a sufficient yield, and its manufacturing method.

  In order to solve the above problems, a thin film device of the present invention has a stacked structure including a first insulator, an oxide semiconductor film, and a second insulator in this order, and an active layer is configured by the oxide semiconductor film. In the thin film device, in the oxide semiconductor film, a first interface layer that is a portion located at an interface with the first insulator, and a second interface layer that is a portion located at an interface with the second insulator; The oxygen vacancy density of at least one of the above is smaller than the oxygen vacancy density of the bulk layer which is a portion other than the first and second interface layers in the oxide semiconductor film.

  In the thin film device of the present invention, it is preferable that the oxygen vacancy density of the first interface layer and the second interface layer is smaller than the oxygen vacancy density of the bulk layer.

In the thin film device of the present invention, the oxide semiconductor film is preferably an amorphous oxide containing at least one element of Zn, Ga, and In.

  Alternatively, in the thin film device of the present invention, it is preferable that the oxide semiconductor film is a crystalline oxide containing at least one element of Zn, Ga, and In.

  In the thin film device of the present invention, the oxide semiconductor film is preferably formed by crystallizing an amorphous oxide by laser irradiation.

  Alternatively, in the thin film device of the present invention, the oxide semiconductor film is formed by dissolving a particulate oxide semiconductor in a solvent, applying or printing the oxide semiconductor solution, and then evaporating the solvent by heat treatment. It is also preferable.

  In the thin film device of the present invention, the laminated structure is preferably formed on an insulating substrate.

  In the thin film device of the present invention, the insulating substrate is preferably a glass substrate or a resin substrate.

  The thin film device of the present invention is preferably, for example, a thin film transistor or a thin film diode.

  The method for manufacturing a thin film device according to the present invention includes the step of forming an oxide semiconductor film on a first insulator and the step of forming a second insulator on the oxide semiconductor film. 1. A method of manufacturing a thin film device having a stacked structure including an insulator, the oxide semiconductor film, and the second insulator, wherein an active layer is formed of the oxide semiconductor film. In addition to the step of forming the two insulators and the oxide semiconductor film, a first interface layer that is a portion located at the interface with the first insulator in the oxide semiconductor film by performing an oxidation treatment And the second interface layer which is a portion located at the interface with the second insulator, the oxygen vacancy density of at least one of the first interface layer and the second interface layer in the oxide semiconductor film Oxygen in the bulk layer that is not part of It is characterized by smaller than the hole density.

  The method for manufacturing a thin film device according to the present invention includes the step of forming an oxide semiconductor film on a first insulator and the step of forming a second insulator on the oxide semiconductor film. 1. A method of manufacturing a thin film device having a laminated structure including an insulator, the oxide semiconductor film, and the second insulator, wherein an active layer is formed of the oxide semiconductor film, wherein the oxide semiconductor film is oxidized The first interface layer, which is a portion located at the interface with the first insulator in the oxide semiconductor film, is formed by alternately repeating the formation of the thin semiconductor layer and the oxidizing treatment a plurality of times. And the second interface layer which is a portion located at the interface with the second insulator, the oxygen vacancy density of at least one of the first interface layer and the second interface layer in the oxide semiconductor film Bulk layer acid that is not part of It is characterized by smaller than vacancy density.

  The method for manufacturing a thin film device according to the present invention includes the step of forming an oxide semiconductor film on a first insulator and the step of forming a second insulator on the oxide semiconductor film. 1. A method of manufacturing a thin film device having a laminated structure including an insulator, the oxide semiconductor film, and the second insulator, wherein an active layer is formed of the oxide semiconductor film, wherein the oxide semiconductor film is oxidized Forming a physical semiconductor thin layer and oxidizing treatment alternately by repeating a plurality of times, separately from the film forming step of the first insulator, the second insulator and the oxide semiconductor film, By performing the oxidizing treatment, the oxide semiconductor film is a first interface layer that is a portion located at the interface with the first insulator and a portion that is located at the interface between the second insulator. At least one of the two interface layers One oxygen vacancy density, is characterized by smaller than the oxygen vacancy density of the oxide semiconductor film bulk layer is the first and a portion other than the second interfacial layer in.

  In the thin film device manufacturing method of the present invention, it is preferable that the oxidizing treatment is a plasma treatment using at least one of oxygen plasma and ozone plasma.

  In the thin film device manufacturing method of the present invention, the stacked structure of the thin film device includes a gate metal film, a gate insulating film as the first insulator, the oxide semiconductor film, and a source / drain metal film. A protective insulating film as the second insulator is formed in this order, and after the formation of the gate insulating film, the oxidation treatment and the formation of the oxide semiconductor film are performed. It is preferable to carry out continuously in this order without exposing to the atmosphere.

  In the thin film device manufacturing method of the present invention, the stacked structure of the thin film device includes a gate metal film, a gate insulating film as the first insulator, the oxide semiconductor film, and a source / drain metal film. And forming a protective insulating film as the second insulator in this order, patterning the oxide semiconductor film into a desired shape, and then performing a reducing treatment and the source / drain metal. It is preferable that the film formation is continuously performed in this order without being exposed to the atmosphere.

  The reducing treatment is preferably a plasma treatment using at least one of rare gas plasma, hydrogen gas plasma, nitrogen gas plasma, and mixed gas plasma thereof.

  In the thin film device manufacturing method of the present invention, the stacked structure of the thin film device includes a gate metal film, a gate insulating film as the first insulator, the oxide semiconductor film, and a source / drain metal film. And forming a protective insulating film as the second insulator in this order, patterning the source / drain metal film into a desired shape, and then performing the oxidation treatment and the protective insulation. It is preferable that the film formation is continuously performed in this order without being exposed to the atmosphere.

  In the thin film device manufacturing method of the present invention, the stacked structure of the thin film device includes a base insulating film as the first insulator, a source / drain metal film, the oxide semiconductor film, and the second insulation. A gate insulating film as a body, a gate metal film, and a protective insulating film are formed in this order, and after the oxide semiconductor film is formed, the oxidation treatment and the gate insulating film It is preferable to continuously perform the film formation in this order without being exposed to the atmosphere.

  In the thin film device manufacturing method of the present invention, the stacked structure of the thin film device includes a base insulating film as the first insulator, a source / drain metal film, the oxide semiconductor film, and the second insulation. A gate insulating film as a body, a gate metal film, and a protective insulating film are formed in this order, and after patterning the source / drain metal film into a desired shape, the oxidation treatment It is preferable that the oxide semiconductor film is continuously formed in this order without being exposed to the atmosphere.

  In the thin film device manufacturing method of the present invention, the stacked structure of the thin film device includes a base insulating film as the first insulator, the oxide semiconductor film, and a gate insulating film as the second insulator. Forming a gate metal film, an interlayer insulating film, a source / drain metal film, and a protective insulating film in this order, and after forming the base insulating film, the oxidizing treatment, It is preferable that the oxide semiconductor film is continuously formed in this order without being exposed to the air.

  In the thin film device manufacturing method of the present invention, the stacked structure of the thin film device includes a base insulating film as the first insulator, the oxide semiconductor film, and a gate insulating film as the second insulator. Forming a gate metal film, an interlayer insulating film, a source / drain metal film, and a protective insulating film in this order, and after forming the oxide semiconductor film, the oxidizing treatment; It is preferable that the gate insulating film is continuously formed in this order without being exposed to the atmosphere.

  In the thin film device manufacturing method of the present invention, the stacked structure of the thin film device includes a gate metal film, a gate insulating film as the first insulator, a source / drain metal film, and the oxide semiconductor film. And forming a protective insulating film as the second insulator in this order, and forming the source / drain metal film in a desired shape, and then performing the oxidation treatment and the oxide semiconductor film. It is preferable that the film formation is continuously performed in this order without being exposed to the atmosphere.

  In the thin film device manufacturing method of the present invention, the stacked structure of the thin film device includes a gate metal film, a gate insulating film as the first insulator, a source / drain metal film, and the oxide semiconductor film. A protective insulating film as the second insulator is formed in this order, and after the oxide semiconductor film is patterned into a desired shape, the oxidation treatment and the formation of the protective insulating film are performed. It is preferable to carry out the film continuously in this order without exposing the film to the atmosphere.

According to the present invention, defects due to oxygen vacancies (defects that generate excess electron donors) at the interface between an oxide semiconductor film and an insulating film can be controlled. That is, it can be suppressed at an unnecessary portion. Therefore, a thin film device having good characteristics can be manufactured with high reproducibility and yield.

It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to the first embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to the first embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to the first embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to the first embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to the first embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to the first embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to the first embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to the first embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a second embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a second embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a second embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a second embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a second embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a second embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a third embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a third embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a third embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a third embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a third embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a fourth embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a fourth embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a fourth embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a fourth embodiment. It is a part of a series of process diagrams showing a method for manufacturing a thin film transistor according to a fourth embodiment. It is a part of a series of process diagrams showing a method for forming an oxide semiconductor film according to a fifth embodiment. It is a part of a series of process diagrams showing a method for forming an oxide semiconductor film according to a fifth embodiment. It is a part of a series of process diagrams showing a method for forming an oxide semiconductor film according to a fifth embodiment. It is a part of a series of process diagrams showing a method for forming an oxide semiconductor film according to a fifth embodiment. It is a part of a series of process diagrams showing a method for forming an oxide semiconductor film according to a fifth embodiment.

  Embodiments according to the present invention will be described below with reference to the drawings.

[First Embodiment]
1 to 8 are a series of process diagrams showing a method of manufacturing the thin film transistor (thin film device) 100 (FIG. 8) according to the first embodiment.

  The thin film transistor 100 according to the present embodiment is a bottom gate staggered thin film transistor.

  Hereinafter, the manufacturing method will be described.

  First, as shown in FIG. 1, after forming a gate metal film on the insulating substrate 10 and patterning the gate metal film to form the gate electrode 11, a gate insulating film ( A first insulator 12 is formed on the insulating substrate 10.

  Next, as shown in FIG. 2, oxygen plasma treatment or other first oxidation treatment (oxidation treatment) 131 is performed on the gate insulating film 12 without being exposed to the atmosphere.

  By this first oxidizing treatment 131, it is possible to make oxygen adhere to the surface of the gate insulating film 12, and for example, when oxygen vacancies occur in the surface layer portion of the gate insulating film 12, the oxygen vacancies Can be eliminated.

  Following the first oxidation treatment 131, the oxide semiconductor film 14 is formed on the gate insulating film 12 as shown in FIG.

  Thereby, in the oxide semiconductor film 14, the first interface layer 14 </ b> A, which is a portion located at the interface with the gate insulating film 12, is oxidized by oxygen previously deposited on the surface of the gate insulating film 12.

  Therefore, oxygen vacancy defects in the first interface layer 14A of the oxide semiconductor film 14 are reduced.

  That is, the oxygen vacancy density of the first interface layer 14 </ b> A of the oxide semiconductor film 14 is smaller than that of the bulk layer 14 </ b> B of the oxide semiconductor film 14.

  Next, as illustrated in FIG. 4, the oxide semiconductor film 14 is patterned into a desired shape.

  Next, as shown in FIG. 5, the oxide semiconductor film 14 is subjected to reducing plasma treatment or other reducing treatment 15.

  Thereby, oxygen vacancy defects are positively formed in the surface layer portion 14 </ b> C of the oxide semiconductor film 14.

  That is, the oxygen vacancy density in the surface layer portion 14 </ b> C of the oxide semiconductor film 14 is larger than that in the bulk layer 14 </ b> B of the oxide semiconductor film 14.

  Next, as shown in FIG. 6, a source / drain metal film is formed over the gate insulating film 12 and the oxide semiconductor film 14, and the source / drain metal film is patterned to form a source / drain electrode. 16 (one is a source electrode and the other is a drain electrode).

  Here, it is desirable that the reducing process 15 of FIG. 5 and the subsequent formation of the source / drain metal film are continuously performed without being exposed to the atmosphere.

  Next, as shown in FIG. 7, an oxygen plasma treatment or other second oxidizing treatment (oxidizing treatment) 132 is performed on the oxide semiconductor film 14 through the space 16 </ b> A between the source / drain electrodes 16.

  As a result, in the surface layer portion 14C (see FIG. 6) of the oxide semiconductor film 14, the second interface layer 14E, which is a portion located at the interval 16A, is oxidized, so that oxygen vacancies in the second interface layer 14E are eliminated. Is reduced.

  That is, the oxygen vacancy density of the second interface layer 14 </ b> E of the oxide semiconductor film 14 is smaller than that of the bulk layer 14 </ b> B of the oxide semiconductor film 14.

  Note that in the surface layer portion 14C (see FIG. 6) of the oxide semiconductor film 14, the portion other than the second interface layer 14E of the oxide semiconductor film 14, that is, the portion located at the interface with the source / drain electrode 16 is 3 interface layer 14D is comprised.

  Next, as shown in FIG. 8, a protective insulating film (second insulator) is formed so as to cover the source / drain electrode 16 and the oxide semiconductor film 14 at the interval 16 </ b> A of the source / drain electrode 16. 18 is deposited.

  Thereby, the thin film transistor 100 is manufactured.

  Note that it is desirable that the second oxidation treatment 132 in FIG. 7 and the subsequent formation of the protective insulating film 18 are continuously performed without being exposed to the atmosphere.

Here, in the oxide semiconductor film 14, the oxygen vacancy density of the first interface layer 14 </ b> A that is a portion located at the interface with the gate insulating film 12 is, for example, 1 × 10 ¹² to 1 × 10 ¹⁸ cm ⁻³ . is there.

The oxygen vacancy density of the bulk layer 14B of the oxide semiconductor film 14 is, for example, 1 × 10 ¹⁶ to 1 × 10 ²⁰ cm ⁻³ .

  The oxygen vacancy density of the first interface layer 14A and the bulk layer 14B can be realized by controlling the film forming conditions. That is, if the oxygen concentration in the atmosphere during film formation is increased, the oxygen vacancy density can be decreased, while if the oxygen concentration in the atmosphere during film formation is decreased, the oxygen vacancy density can be increased. .

2 is performed, the electron density of the first interface layer 14A can be reduced moderately, and the thin film transistor 100 has a drain current on / off ratio of 5 digits or more (1 × 10 ⁴ or more). Good switching characteristics can be obtained.

In the oxide semiconductor film 14, the oxygen vacancy density of the third interface layer 14 </ b> D which is a portion located at the interface with the source / drain electrode 16 is, for example, 1 × 10 ¹⁹ to 1 × 10 ²² cm ⁻³ . is there.

In the oxide semiconductor film 14, the oxygen vacancy density of the second interface layer 14 </ b> E that is a portion located at the interface with the protective insulating film 18 is, for example, 1 × 10 ¹⁶ to 1 × 10 ²⁰ cm ⁻³ . .

  The oxygen vacancy density of the third interface layer 14D and the second interface layer 14E can also be realized by controlling the film forming conditions. That is, if the oxygen concentration in the atmosphere during film formation is increased, the oxygen vacancy density can be decreased, while if the oxygen concentration in the atmosphere during film formation is decreased, the oxygen vacancy density can be increased. .

  Since the reducing treatment 15 of FIG. 5 is performed, the electron density of the third interface layer 14D can be increased moderately, and the third interface layer 14D can have a function as an ohmic contact layer.

  In addition, since the oxidation treatment 13 of FIG. 7 is performed, the electron density of the second interface layer 14E can be moderately reduced, and a function of efficiently reducing the off-current caused by the back channel electron current is provided. Can do.

  According to the first embodiment as described above, the gate electrode 11, the gate insulating film (first insulator) 12, the oxide semiconductor film 14, the source / drain metal 16, and the protective insulating film (the second insulating film). (Insulator) 18 and defects due to oxygen vacancies (defects that generate excess electron donors) at the interface between the oxide semiconductor film 14 and the insulating films 12 and 18 of the thin film transistor 100 having a stacked structure in which the insulator 18 is formed in this order. ) Can be controlled.

  That is, it can be actively generated at a place where a defect is necessary, and can be suppressed at an unnecessary place.

  Specifically, after the first oxidizing treatment 131 shown in FIG. 2 is performed, the oxide semiconductor film 14 is formed as shown in FIG. Oxygen vacancy defects in the interface layer 14A located at the interface can be reduced. That is, the oxygen vacancy density of the interface layer 14A can be made smaller than that of the bulk layer 14B.

  Further, by performing the reducing treatment 15 shown in FIG. 5, the surface layer portion 14C of the oxide semiconductor film 14 (specifically, the surface layer portion 14C is positioned at the interface with the source / drain electrode 16). The third interface layer located at the interface with the source / drain electrode 16 by positively forming oxygen vacancy defects in the three interface layer 14D (FIGS. 7 and 8) and acting as an electron donor. 14D can be made more n-type to facilitate the formation of an ohmic contact junction.

  Further, by performing the second oxidizing treatment 132 shown in FIG. 7, the oxygen vacancy of the second interface layer 14E which is a portion other than the source / drain regions (inside the opening 16A) in the surface layer portion 14C of the oxide semiconductor film 14 is performed. Hole defects can be reduced and off current of the thin film transistor 100 can be reduced.

[Second Embodiment]
9 to 14 are a series of process diagrams showing a method of manufacturing the thin film transistor (thin film device) 200 (FIG. 14) according to the first embodiment.

  The thin film transistor 200 according to this embodiment is a top gate staggered thin film transistor.

  Hereinafter, the manufacturing method will be described.

  First, as shown in FIG. 9, after a base insulating film (first insulator) 21 is formed on the insulating substrate 10, a source / drain metal film is formed on the base insulating film 21, By patterning the source / drain metal film, a source / drain electrode 16 (one is a source electrode and the other is a drain electrode) is formed.

  Next, as shown in FIG. 10, oxygen plasma treatment or other first oxidizing treatment 131 is performed.

  By this first oxidizing treatment 131, oxygen can be attached to the surface of the base insulating film 21, and for example, when oxygen vacancies occur in the surface layer portion of the base insulating film 21, the oxygen vacancies are generated. Can be eliminated.

  Next, after forming the oxide semiconductor film 14 on the base insulating film 21 and the source / drain electrodes 16, the oxide semiconductor film 14 is patterned into a desired shape as shown in FIG.

  Here, in the oxide semiconductor film 14, the first interface layer 14 </ b> A, which is a portion located at the interface with the base insulating film 21, is oxidized by oxygen that has been previously deposited on the surface of the base insulating film 21.

  Therefore, oxygen vacancy defects in the first interface layer 14A of the oxide semiconductor film 14 are reduced.

  That is, the oxygen vacancy density of the first interface layer 14A is smaller than that of the bulk layer 14B of the oxide semiconductor film 14.

  Note that the oxidizing treatment 13 and the formation of the oxide semiconductor film 14 in FIG. 10 are preferably performed continuously without being exposed to the air.

  Next, as shown in FIG. 12, the oxide semiconductor film 14 is subjected to oxygen plasma treatment or other second oxidizing treatment 132.

  As a result, the second interface layer 14E of the oxide semiconductor film 14 is oxidized, so that oxygen vacancies in the second interface layer 14E are reduced.

  That is, the oxygen vacancy density of the second interface layer 14E is smaller than that of the bulk layer 14B of the oxide semiconductor film 14.

  Next, as shown in FIG. 13, a gate insulating film (second insulator) 12 covering the oxide semiconductor film 14 is formed on the source / drain electrode 16, without being exposed to the atmosphere.

  Next, as shown in FIG. 14, after forming the gate electrode 11 on the gate insulating film 12, a protective insulating film 18 covering the gate electrode 11 is formed on the gate insulating film 12.

  Thereby, the thin film transistor 200 is manufactured.

  According to the second embodiment as described above, the base insulating film (first insulator) 21, the source / drain electrodes 16, the oxide semiconductor film 14, the gate insulating film (second insulator) 12, and The defects due to oxygen vacancies are controlled at the interface between the oxide semiconductor film 14 and the insulating films 21 and 12 of the thin film transistor 200 having a stacked structure in which the gate electrode 11 and the protective insulating film 18 are formed in this order. it can.

  Specifically, after the first oxidation treatment 131 shown in FIG. 10 is performed, the oxide semiconductor film 14 is formed as shown in FIG. Oxygen vacancy defects in the interface layer 14A located at the interface can be reduced. That is, the oxygen vacancy density of the interface layer 14A can be made smaller than that of the bulk layer 14B.

  In addition, by performing the second oxidation treatment 131 shown in FIG. 12, in the oxide semiconductor film 14, oxygen vacancies in the second interface layer 14E that are located at the interface with the gate insulating film 12 are reduced. As a result, the electron density of the second interface layer 14E can be moderately reduced, and the off current of the thin film transistor 200 due to the back channel electron current can be efficiently reduced.

[Third Embodiment]
15 to 19 are a series of process diagrams showing a method of manufacturing the thin film transistor (thin film device) 300 (FIG. 19) according to the third embodiment.

  The thin film transistor 300 according to the present embodiment is a top gate planar type thin film transistor.

  Hereinafter, the manufacturing method will be described.

  First, as shown in FIG. 15, after a base insulating film (first insulator) 21 is formed on the insulating substrate 10, oxygen plasma treatment or other first oxidizing property is applied to the base insulating film 21. Processing 131 is performed.

  After that, the oxide semiconductor film 14 is formed over the base insulating film 21 without being exposed to the air (see FIG. 16).

  Here, in the oxide semiconductor film 14, the first interface layer 14 </ b> A, which is a portion located at the interface with the base insulating film 21, is oxidized by oxygen that has been previously deposited on the surface of the base insulating film 21.

  Therefore, oxygen vacancy defects in the first interface layer 14A of the oxide semiconductor film 14 are reduced.

  That is, the oxygen vacancy density of the first interface layer 14A is smaller than that of the bulk layer 14B of the oxide semiconductor film 14.

  Further, as shown in FIG. 16, the oxide semiconductor film 14 is patterned into a desired shape.

  Further, as shown in FIG. 16, the oxide semiconductor film 14 is subjected to oxygen plasma treatment or other second oxidizing treatment 132.

  As a result, the second interface layer 14E of the oxide semiconductor film 14 is oxidized, so that oxygen vacancies in the second interface layer 14E are reduced.

  That is, the oxygen vacancy density of the second interface layer 14E is smaller than that of the bulk layer 14B of the oxide semiconductor film 14.

  Next, as shown in FIG. 17, a gate insulating film (second insulator) 12 that covers the oxide semiconductor film 14 is formed on the base insulating film 21 without being exposed to the atmosphere. A gate electrode 11 is formed thereon.

  Next, as shown in FIG. 18, after an interlayer insulating film 23 covering the gate electrode 11 is formed on the gate insulating film 12, the contact holes 19 to the source / drain regions are formed in the interlayer insulating film 23 and the gate insulating film. 12 is formed.

  Next, as shown in FIG. 19, after forming the source / drain electrode 16 (one is a source electrode and the other is a drain electrode) from the contact hole 19 to the gate insulating film 12, the source / drain electrode 16 is formed. A protective insulating film 18 is formed on the interlayer insulating film 23 so as to cover it.

  Thereby, the thin film transistor 300 is manufactured.

  According to the third embodiment as described above, the base insulating film (first insulator) 21, the oxide semiconductor film 14, the gate insulating film (second insulator) 12, the gate electrode 11, and the interlayer Oxygen at the interface between the oxide semiconductor film 14 and the insulating films 21 and 12 of the thin film transistor 300 having a stacked structure in which the insulating film 23, the source / drain metal film 16, and the protective insulating film 18 are formed in this order. It is possible to control defects due to vacancies (defects that generate excess electron donors).

  Specifically, after the first oxidation treatment 131 shown in FIG. 15 is performed, the oxide semiconductor film 14 is formed as shown in FIG. Oxygen vacancy defects in the interface layer 14A located at the interface can be reduced. That is, the oxygen vacancy density of the interface layer 14A can be made smaller than that of the bulk layer 14B.

  In addition, by performing the second oxidation treatment 132 illustrated in FIG. 16, oxygen vacancies in the second interface layer 14 </ b> E that are located at the interface with the gate insulating film 12 in the oxide semiconductor film 14 are reduced. Thus, the electron density of the second interface layer 14E can be appropriately reduced, and the off-state current of the thin film transistor 300 caused by the back channel electron current can be efficiently reduced.

[Fourth Embodiment]
20 to 24 are a series of process diagrams showing a method of manufacturing a thin film transistor (thin film device) 400 according to the fourth embodiment.

  The thin film transistor 400 according to the present embodiment is a bottom gate planar type thin film transistor.

  Hereinafter, the manufacturing method will be described.

  First, as shown in FIG. 20, a gate metal film is formed on the insulating substrate 10, the gate metal film is patterned to form a gate electrode 11, and a gate insulating film (first film) covering the gate electrode 11 is formed. (1 insulator) 12 is formed on the insulating substrate 10.

  Next, as shown in FIG. 21, a source / drain metal film is formed on the gate insulating film 12, and the source / drain metal film is patterned, whereby the source / drain electrode 16 (one is the source electrode and the other is the other). Is formed, and an oxygen plasma treatment or other first oxidizing treatment 131 is applied to the gate insulating film 12 through the space 16A between the source / drain electrodes 16.

  By this first oxidizing treatment 131, it is possible to make oxygen adhere to the surface of the gate insulating film 12, and for example, when oxygen vacancies occur in the surface layer portion of the gate insulating film 12, the oxygen vacancies Can be eliminated.

  Subsequent to the first oxidation treatment 131, the oxide semiconductor film 14 is formed on the gate insulating film 12 as shown in FIG. 22 without exposure to the atmosphere, and is patterned into a desired shape.

  Thereby, in the oxide semiconductor film 14, the first interface layer 14 </ b> A, which is a portion located at the interface with the gate insulating film 12, is oxidized by oxygen previously deposited on the surface of the gate insulating film 12.

  Therefore, oxygen vacancy defects in the first interface layer 14A of the oxide semiconductor film 14 are reduced.

  That is, the oxygen vacancy density of the first interface layer 14 </ b> A of the oxide semiconductor film 14 is smaller than that of the bulk layer 14 </ b> B of the oxide semiconductor film 14.

  Next, as illustrated in FIG. 23, the oxide semiconductor film 14 is subjected to oxygen plasma treatment or other second oxidation treatment 132.

  Subsequently, as shown in FIG. 24, a protective insulating film (second insulator) 18 covering the oxide semiconductor film 14 is formed on the source / drain electrode 16 without being exposed to the atmosphere.

  Thereby, the thin film transistor 400 is manufactured.

  According to the fourth embodiment as described above, the gate electrode 11, the gate insulating film (first insulator) 12, the source / drain electrodes 16, the oxide semiconductor film 14, and the protective insulating film (second Insulator) 18 and defects due to oxygen vacancies (defects that generate excess electron donors) at the interface between the oxide semiconductor film 14 and the insulating films 12 and 18 of the thin film transistor 400 having a stacked structure in which the stacked layers are formed in this order. ) Can be controlled.

  Specifically, after the first oxidizing treatment 131 shown in FIG. 21 is performed, the oxide semiconductor film 14 is formed as shown in FIG. Oxygen vacancy defects in the interface layer 14A located at the interface can be reduced. That is, the oxygen vacancy density of the interface layer 14A can be made smaller than the oxygen vacancy density of the bulk layer 14B.

  In addition, by performing the second oxidation treatment 131 shown in FIG. 23, oxygen vacancies in the second interface layer 14 </ b> E that are located at the interface with the protective insulating film 18 in the oxide semiconductor film 14 are reduced. Thus, the electron density of the second interface layer 14E can be appropriately reduced, and the off current of the thin film transistor 400 due to the back channel electron current can be efficiently reduced.

[Fifth Embodiment]
In the first to fourth embodiments, the example in which the oxide semiconductor film 14 of the thin film transistors 100, 200, 300, and 400 is formed at one time has been described. In the fifth embodiment, the oxide semiconductor film 14 is formed. An example in which a film is formed in a plurality of layers will be described.

  Hereinafter, a method for forming the oxide semiconductor film 14 in this embodiment will be described.

  First, as shown in FIG. 25, a very thin oxide semiconductor film 51 is formed on the first insulator 50. Here, the first insulator 50 corresponds to the gate insulating film 12 in the first embodiment (FIG. 8) and the fourth embodiment (FIG. 24), for example, and the second embodiment (FIG. 14) and In the third embodiment (FIG. 19), it corresponds to the base insulating film 21.

  Next, as illustrated in FIG. 26, the oxide semiconductor film 51 is subjected to oxygen plasma treatment or other oxidizing treatment 52.

  Thereby, the surface layer portion of the oxide semiconductor film 51 is oxidized.

  Next, as illustrated in FIG. 27, a very thin oxide semiconductor film 51 is formed over the oxide semiconductor film 51.

  Next, as illustrated in FIG. 28, the oxide semiconductor film 51 is subjected to an oxidation treatment 52.

  Next, as illustrated in FIG. 29, a very thin oxide semiconductor film 51 is formed over the oxide semiconductor film 51.

  Further, the oxide semiconductor film 14 is formed by repeatedly performing the processes in FIGS. 26 and 27 as many times as necessary.

  According to the fifth embodiment as described above, the oxide semiconductor film 14 is formed by alternately repeating the film formation of the oxide semiconductor film (oxide semiconductor thin layer) 51 and the oxidizing treatment 52 a plurality of times. Thus, each oxide semiconductor thin layer 51 can be sufficiently oxidized, and the oxide semiconductor film 14 having a desired film quality can be obtained with high accuracy.

  In the first to fifth embodiments described above, as the oxide semiconductor film 14, for example, an amorphous oxide or a crystalline oxide containing at least one element of Zn, Ga, and In is used. it can. Such an oxide semiconductor film 14 can be formed by sputtering, vapor deposition, CVD, or the like, for example. In particular, the oxide semiconductor film 14 of a crystalline oxide film can be formed by irradiating an amorphous film with a XeCl excimer laser or other laser. This is because these oxide semiconductor films 14 are almost transparent to visible light, for example, but are opaque and absorb to a XeCl excimer laser having a wavelength of 308 nm. Of course, it can also be crystallized by irradiating laser or light having a shorter wavelength than other visible light. These oxide semiconductor films 14 can also be formed by dissolving a particulate oxide semiconductor in a solvent, applying or printing the oxide semiconductor solution, and then evaporating the solvent by heat treatment.

  In addition, regarding the oxidizing process or reducing process in the first to fifth embodiments, an oxidizing plasma process or a reducing plasma process can be applied. As the oxidizing plasma treatment, plasma treatment including at least oxygen plasma or ozone plasma is possible. As the reducing plasma treatment, plasma treatment using rare gas plasma such as Ar or He, hydrogen plasma, nitrogen gas plasma, or a mixed gas plasma of any combination thereof is possible.

  In each of the above embodiments, the first insulator (the gate insulating film 12 or the base insulating film 21 in each of the above embodiments) and the second insulator (the protective insulating film 18 or the gate insulating film in each of the above embodiments). In the oxide semiconductor film 14 sandwiched between 12), the first interface layer 14A, which is a portion located at the interface with the first insulator, and the second interface layer, which is a portion located at the interface with the second insulator 14E has been described as an example in which both are smaller than the oxygen vacancy density of the bulk layer 14B, but depending on the desired configuration of the thin film transistor, either the first interface layer 14A or the second interface layer 14E Only one of the oxygen vacancy densities may be smaller than the oxygen vacancy density of the bulk layer 14B.

  Further, in each of the above embodiments, the example in which the gate insulating film 12 or the base insulating film 21 as the first insulator is formed on the insulating substrate 10 has been described. However, the present invention is not limited to this example, and the insulating In some cases, the conductive substrate 10 is used as the first insulator. However, in consideration of yield and characteristic stability, it is preferable to form a first insulator (for example, the gate insulating film 12 or the base insulating film 21) on the insulating substrate 10.

  In each of the above embodiments, the thin film transistors 100, 200, 300, and 400 are illustrated as thin film devices. However, the present invention is not limited to this example, and can be applied to thin film diodes.

  A first embodiment will be described with reference to FIGS.

  First, as shown in FIG. 1, a Cr metal film as a gate metal film is formed on a glass substrate as an insulating substrate 10 by sputtering, and then a Cr metal film is desired using a normal photolithography process. The gate electrode 11 was patterned.

  Thereafter, a silicon nitride film as the gate insulating film 12 was formed to a thickness of 300 nm by sputtering.

  Thereafter, the surface of the silicon nitride film was oxidized by performing the first oxidation treatment 131 by exposing the gate insulating film 12 to oxygen plasma as shown in FIG.

  Further, an oxide semiconductor film 14 made of InGaZnO 4 was formed to a thickness of 100 nm by sputtering without exposing to the atmosphere (FIG. 3).

As a sputtering target, a sintered body of InGaZnO ₄ was used, but an InGaZnO ₄ compound was formed by sputtering and reacting on the substrate with oxides of respective metals of In, Ga and Zn individually. Also good.

The above-described gate silicon nitride film formation, oxygen plasma treatment, and InGaZnO ₄ oxide semiconductor film 14 are formed by, for example, the same sputtering apparatus in a vacuum state (reduced pressure state). The process can be performed continuously.

  After that, the oxide semiconductor film 14 was patterned into a desired island shape using a normal photolithography process (FIG. 4).

  Subsequently, the oxide semiconductor film 14 was exposed to Ar plasma as the reducing treatment 15 (FIG. 5).

  By exposing to Ar plasma in this manner, oxygen vacancies are formed in the surface layer portion 14C of the oxide semiconductor film 14, and the resistivity value of the surface layer 14C of the oxide semiconductor film 14 is reduced to about 1 / 100,000 of the value before processing. The value decreased to an appropriate value as a source / drain region.

  After this Ar plasma treatment, a Cr film was continuously formed as a source / drain metal without being exposed to the atmosphere, and a source / drain electrode 16 was formed by patterning into a desired shape (FIG. 6).

  Further, the surface layer 14C of the oxide semiconductor film 14 was exposed to oxygen plasma through the space 16A between the source / drain electrodes 16 to perform the second oxidation treatment 132 (FIG. 7).

  This oxygen plasma treatment is performed for the purpose of oxidizing the surface layer portion (second interface layer 14E) of the oxide semiconductor film 14 between the source / drain electrodes 16 and reducing excess donor electrons caused by oxygen vacancies. Thus, by reducing the oxygen vacancies, the off current value of the thin film transistor 100 can be reduced by about two orders of magnitude.

  Thereafter, a silicon nitride film was continuously formed as the protective insulating film 18 by a 300 nm sputtering method without being exposed to the atmosphere.

  Through the above process, the thin film transistor 100 was obtained (FIG. 8).

  Next, Embodiment 2 will be described with reference to FIGS.

  On the resin substrate as the insulating substrate 10, a silicon nitride film as the base insulating film 21 is formed to a thickness of 300 nm by a sputtering method, and then a Mo metal film is formed. Thereafter, the Mo metal film is formed using a normal photolithography process. Source / drain electrodes 16 were formed by patterning the film into a desired shape (FIG. 9).

  Subsequently, as the first oxidizing process 131, a process of exposing the base insulating film 21 to oxygen plasma through the space 16A between the source / drain electrodes 16 was performed (FIG. 10).

Subsequently, an oxide semiconductor film 14 made of InGaZnO ₄ was continuously formed to a film thickness of 60 nm at room temperature by a sputtering method without being exposed to the atmosphere, and the oxide semiconductor film 14 was patterned into a desired island shape ( FIG. 11).

  After that, the surface layer portion (second interface layer 14E) of the oxide semiconductor film 14 was exposed to oxygen plasma as the second oxidizing treatment 132, and the surface layer portion was oxidized to reduce oxygen vacancies in the surface layer portion (FIG. 12).

  Thereafter, a silicon nitride film as the gate insulating film 12 was continuously formed to 400 nm by sputtering without exposing to the atmosphere (FIG. 13).

  Thereafter, the gate electrode 11 was formed of Al, and a silicon nitride film as the protective insulating film 18 was formed by sputtering to a thickness of 300 nm, whereby the thin film transistor 200 was obtained (FIG. 14).

  By performing the oxygen plasma treatment as described above, the electron density in the channel region of the thin film transistor was well controlled, and good switching characteristics with a drain current on / off ratio of 5 digits or more were realized.

  In order to obtain better characteristics, after the oxide semiconductor film 14 is formed to a thickness of 60 nm, oxygen plasma treatment is continuously performed, and then the gate insulating film 12 made of silicon nitride is continuously formed. Part (film thickness 50 nm: first gate insulating film) is formed.

  Thereafter, the laminated film of the first gate insulating film and the oxide semiconductor film 14 is patterned into a desired island shape, and the remaining part of the gate insulating film 12 made of silicon nitride (thickness 350 nm: second gate insulating film) ).

  The gate insulating film thickness of the thin film transistor 200 formed by such a method is 400 nm, which is the same as the above case. However, an important difference is that the interface between the oxide semiconductor film 14 and the gate insulating film 12 is once in the atmosphere. (In the case described above, the upper surface of the oxide semiconductor film 14 is exposed to the atmosphere or a photolithography process when the oxide semiconductor film 14 is patterned).

  In this manner, when the interface between the oxide semiconductor film 14 and the insulating film (for example, the gate insulating film 12) is not exposed to the atmosphere, generation of oxygen vacancy defects and other impurity defects can be suppressed. Excellent switching characteristics can be realized.

  Next, Embodiment 3 will be described with reference to FIGS.

  A 300 nm silicon nitride film as a base insulating film 21 is formed on a glass substrate as the insulating substrate 10 by sputtering, and the surface of the base film insulating film 21 is exposed to oxygen plasma to perform a first oxidation treatment 131. As a result, the surface of the silicon nitride film was oxidized (FIG. 15).

Thereafter, an oxide semiconductor film 14 made of InGaZnO ₄ was formed to a thickness of 60 nm at room temperature by a sputtering method. The amorphous oxide semiconductor film 14 deposited at room temperature was crystallized by irradiating it with XeCl excimer laser and melting and solidifying it. Thereafter, the polycrystalline oxide semiconductor film 14 was patterned into a desired island shape. Subsequently, the oxygen vacancy defects were reduced by oxidizing the surface layer portion (second interface layer 14E) of the polycrystalline oxide semiconductor film 14 by oxygen plasma treatment (second oxidative treatment 132) (FIG. 16).

When the oxide semiconductor film 14 made of InGaZnO _{4 is} crystallized by laser irradiation, this oxygen plasma treatment is very important because oxygen escapes in a very high temperature molten state.

  After the oxygen plasma treatment, a silicon nitride film as a gate insulating film 12 was continuously formed to a thickness of 100 nm by a sputtering method without being exposed to the atmosphere. Furthermore, the gate electrode 11 was formed using Al (FIG. 17).

  Subsequently, a 400 nm silicon oxide film as an interlayer insulating film 23 was formed to form contact holes 19 for source / drain electrodes (FIG. 18).

  Next, after forming the source / drain electrodes 16 using Al, a silicon nitride film as a protective insulating film 18 was formed to a thickness of 300 nm to obtain the thin film transistor 300.

  In Example 3, since the oxide semiconductor film 14 was crystallized as compared with Examples 1 and 2, an electron mobility of about 5 to 10 times higher was obtained.

  Industrial applicability of the present invention includes pixel drive elements for flat panel displays such as liquid crystal displays and organic EL displays. In particular, oxide semiconductors are transparent, so when applied to pixel drive elements for liquid crystal displays, the amount of light transmitted from the backlight is greater than when using conventional silicon semiconductors, enabling a brighter high-performance display. It becomes. Such a driving element is not limited to a three-terminal thin film transistor, and may be a two-terminal thin film diode.

  In addition, even when an oxide semiconductor film is formed at room temperature, it has an electron mobility that is about an order of magnitude higher than that of a conventional typical amorphous silicon film formed at 300 ° C., and thus has excellent characteristics even at room temperature. A thin film transistor array can be formed. In particular, by using the oxidizing or reducing plasma treatment of the present invention, the oxygen vacancy density in the oxide semiconductor interface region that governs the electrical characteristics of the thin film transistor can be controlled by a low temperature process. Accordingly, good characteristics can be obtained even on a resin substrate having low heat resistance, and therefore, application to a flexible resin substrate display is possible.

DESCRIPTION OF SYMBOLS 10 Insulating substrate 11 Gate electrode 12 Gate insulating film 131 1st oxidizing process 132 2nd oxidizing process 14 Oxide semiconductor 14A 1st interface layer 14E 2nd interface layer 14B Bulk layer 15 Reducible process 16 Source / drain electrode 18 Protective insulating film 19 Contact hole 21 Base insulating film 23 Interlayer insulating film 50 Insulating film 100 Thin film transistor (thin film device)
200 Thin film transistor (thin film device)
300 Thin Film Transistor (Thin Film Device)
400 Thin film transistor

Claims (16)

A stacked structure having a first insulator, a source / drain electrode, an oxide semiconductor film, a second insulator, a gate metal film, and a third insulator in this order, is activated by the oxide semiconductor film. In the thin film device in which the layers are configured,
In the oxide semiconductor film,
The oxide semiconductor film has an oxygen vacancy density of a first interface layer that is a portion located at the interface with the first insulator and a second interface layer that is a portion located at the interface with the second insulator. A thin film device having a density smaller than an oxygen vacancy density of a bulk layer other than the first interface layer and the second interface layer. A stacked structure including a fourth insulator, an oxide semiconductor film, a fifth insulator, a gate metal film, a sixth insulator, a source / drain electrode, and a seventh insulator in this order; In the thin film device in which the active layer is constituted by the oxide semiconductor film,
In the oxide semiconductor film,
The oxide semiconductor film has an oxygen vacancy density of a fourth interface layer that is a portion located at the interface with the fourth insulator and a fifth interface layer that is a portion located at the interface with the fifth insulator. A thin film device characterized by being smaller than the oxygen vacancy density of a bulk layer which is a part other than the fourth interface layer and the fifth interface layer. A stacked structure including a gate metal film, an eighth insulator, a source / drain electrode, an oxide semiconductor film, and a ninth insulator in this order is provided, and an active layer is configured by the oxide semiconductor film In thin film devices,
In the oxide semiconductor film,
The oxide semiconductor film has an oxygen vacancy density of an eighth interface layer that is a portion located at the interface with the eighth insulator and a ninth interface layer that is a portion located at the interface with the ninth insulator. The thin film device according to claim 1, wherein the oxygen vacancy density of the bulk layer, which is a portion other than the eighth interface layer and the ninth interface layer, is smaller.   4. The thin film device according to claim 1, wherein the source / drain electrode and the oxide semiconductor film are in contact with each other. 5. 5. The thin film device according to claim 1, wherein the oxide semiconductor film is an amorphous oxide containing at least one element of Zn, Ga, and In. 6. 5. The thin film device according to claim 1, wherein the oxide semiconductor film is a crystalline oxide containing at least one element of Zn, Ga, and In. 6. The thin film device according to claim 6, wherein the oxide semiconductor film is formed by crystallizing an amorphous oxide by laser irradiation. The oxide semiconductor film is formed by dissolving a particulate oxide semiconductor in a solvent, applying or printing the oxide semiconductor solution, and then evaporating the solvent by heat treatment. Item 5. The thin film device according to any one of Items 1 to 4. The thin film device according to any one of claims 1 to 8, wherein the laminated structure is formed on an insulating substrate. The thin film device according to claim 9, wherein the insulating substrate is a glass substrate or a resin substrate. The stacked structure of the thin film device includes a base insulating film as the first insulator, a source / drain metal film, the oxide semiconductor film, a gate insulating film as the second insulator, and a gate metal film. And a protective insulating film as the third insulator are formed in this order,
2. The thin film according to claim 1, wherein after the formation of the oxide semiconductor film, the oxidizing treatment and the formation of the gate insulating film are sequentially performed in this order without being exposed to the atmosphere. Device manufacturing method. The stacked structure of the thin film device includes a base insulating film as the first insulator, a source / drain metal film, the oxide semiconductor film, a gate insulating film as the second insulator, and a gate metal film. And a protective insulating film as the third insulator are formed in this order,
After patterning the source / drain metal film into a desired shape, the oxidation treatment and the formation of the oxide semiconductor film are successively performed in this order without being exposed to the atmosphere. The method for manufacturing a thin film device according to claim 1. The stacked structure of the thin film device includes a base insulating film as the fourth insulator, the oxide semiconductor film, a gate insulating film as the fifth insulator, a gate metal film, and the sixth insulator. Forming an interlayer insulating film, a source / drain metal film, and a protective insulating film as the seventh insulator in this order,
3. The thin film according to claim 2, wherein after the formation of the base insulating film, the oxidizing treatment and the formation of the oxide semiconductor film are continuously performed in this order without being exposed to the atmosphere. Device manufacturing method. The stacked structure of the thin film device includes a base insulating film as the fourth insulator, the oxide semiconductor film, a gate insulating film as the fifth insulator, a gate metal film, and the sixth insulator. Forming an interlayer insulating film, a source / drain metal film, and a protective insulating film as the seventh insulator in this order,
3. The thin film according to claim 2, wherein after the formation of the oxide semiconductor film, the oxidation treatment and the formation of the gate insulating film are successively performed in this order without being exposed to the atmosphere. Device manufacturing method. The stacked structure of the thin film device includes a gate metal film, a gate insulating film as the eighth insulator, a source / drain metal film, the oxide semiconductor film, and a protective insulating film as the ninth insulator. And by forming a film in this order,
The oxide film and the formation of the oxide semiconductor film are successively performed in this order without being exposed to the air after the source / drain metal film is patterned into a desired shape. Item 4. A method for manufacturing a thin film device according to Item 3. The stacked structure of the thin film device includes a gate metal film, a gate insulating film as the eighth insulator, a source / drain metal film, the oxide semiconductor film, and a protective insulating film as the ninth insulator. And by forming a film in this order,
4. The oxide semiconductor film is formed in a desired shape, and thereafter, an oxidizing treatment and a film formation of the protective insulating film are successively performed in this order without being exposed to the atmosphere. A method for producing the thin film device according to 1.

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