KR20190060260A - Thin film trnasistor having hydrogen blocking layer, method for manufacturing the same and display device comprising the same - Google Patents

Abstract

According to an embodiment of the present invention, a thin film transistor comprises: an oxide semiconductor layer on a substrate; a gate electrode which is insulated from the oxide semiconductor layer and overlaps at least a part of the oxide semiconductor layer; a source electrode connected to the oxide semiconductor layer; and a drain electrode spaced apart from the source electrode and connected to the oxide semiconductor layer. The oxide semiconductor layer includes a hydrogen blocking layer on the substrate and an active layer on the hydrogen blocking layer. The hydrogen blocking layer includes gallium (Ga), zinc (Zn), and indium in an amount of 5 % or less in comparison to the mixed amount of gallium (Ga) and zinc (Zn), based on the number of atoms, and has the density of [(In)/(Ga+Zn)<=0.05] and 5.9 cm^3 or more. Thus, excellent hydrogen blocking properties as well as reduced thickness can be achieved.

Description

TECHNICAL FIELD [0001] The present invention relates to a thin film transistor having a hydrogen barrier layer, a method of manufacturing the thin film transistor, and a display device including the same. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a thin film transistor having a hydrogen barrier layer, a method of manufacturing such a thin film transistor, and a display device including such a thin film transistor.

Transistors are widely used as switching devices or driving devices in the field of electronic devices. In particular, since a thin film transistor can be manufactured on a glass substrate or a plastic substrate, it can be used as a switching element of a display device such as a liquid crystal display device or an organic light emitting device It is widely used.

The thin film transistor includes an amorphous silicon thin film transistor in which amorphous silicon is used as an active layer, a polycrystalline silicon thin film transistor in which polycrystalline silicon is used as an active layer, and a polycrystalline silicon thin film transistor in which an oxide semiconductor is used as an active layer Oxide semiconductor thin film transistor.

The amorphous silicon thin film transistor (a-Si TFT) has a merit that a manufacturing process time is short and a production cost is low because amorphous silicon is deposited in a short time to form an active layer, The current driving capability is low and the threshold voltage is changed. Therefore, the organic EL device has a disadvantage that its use is limited to the active matrix organic light emitting device (AMOLED).

A polycrystalline silicon thin film transistor (poly-Si TFT) is formed by crystallizing amorphous silicon after the amorphous silicon is deposited. Since a process for crystallizing amorphous silicon is required in the process of manufacturing a polycrystalline silicon thin film transistor, the manufacturing cost is increased due to an increase in the number of processes, and a crystallization process is performed at a high process temperature. Therefore, the polycrystalline silicon thin film transistor is applied to a large- There is a difficulty in having. Further, due to the polycrystalline characteristics, it is difficult to secure the uniformity of the polycrystalline silicon thin film transistor.

Since an oxide semiconductor TFT can form an oxide constituting the active layer at a relatively low temperature and has a high mobility and a large resistance change depending on the content of oxygen, Can be easily obtained. Further, due to the nature of the oxide, the oxide semiconductor is transparent, which is also advantageous for realizing a transparent display. However, due to the penetration of hydrogen by contact with the insulating layer or the protective layer, oxygen deficiency or the like may occur in the oxide semiconductor, so that reliability of the oxide semiconductor may be deteriorated.

One embodiment of the present invention is to provide a thin film transistor including a hydrogen barrier layer having a very thin thickness and excellent hydrogen barrier properties.

Another embodiment of the present invention is to provide a method of manufacturing a thin film transistor including a hydrogen barrier layer having a very thin thickness and excellent hydrogen barrier properties.

Another embodiment of the present invention is to provide a display device including such a thin film transistor.

According to an aspect of the present invention, there is provided a semiconductor device comprising: an oxide semiconductor layer on a substrate; a gate electrode which is insulated from the oxide semiconductor layer and overlaps at least part of the oxide semiconductor layer; And a drain electrode spaced apart from the source electrode and connected to the oxide semiconductor layer, wherein the oxide semiconductor layer includes a hydrogen blocking layer on the substrate and an active layer on the hydrogen blocking layer, (In) / (Ga + Zn) ≤ 0.05], a density of not less than 5.9 cm ^{3, and a} density of not less than 5.9 cm ³ , based on the total amount of gallium (Ga) The thin film transistor according to claim 1,

The hydrogen barrier layer is formed by metal organic chemical vapor deposition (MOCVD).

The hydrogen barrier layer has a thickness of 0.5 to 3.0 nm.

The hydrogen barrier layer contains indium (In) in an amount of 3% or less of the mixed amount of gallium (Ga) and zinc (Zn) on the basis of the atomic number [(In) / (Ga + Zn) ≤ 0.03].

The hydrogen barrier layer may further include at least one of tungsten (W), chrome (Cr), molybdenum (Mo), and titanium (Ti).

The thin film transistor includes indium [In] / (Ga + Zn) ≤ 0.01 in an amount of 1% or less of the mixed amount of gallium (Ga) and zinc (Zn) on the basis of atomic number.

The thin film transistor further includes a first insulating film disposed between the substrate and the oxide semiconductor layer.

The oxide semiconductor layer has a density of 6.5 cm &lt; ³ &gt; or less.

And the gate electrode is disposed between the substrate and the first insulating film. Further, the gate electrode is disposed on the first insulating film.

According to another embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming an oxide semiconductor layer on a substrate; forming a gate electrode that is insulated from the oxide semiconductor layer and overlaps at least a part of the oxide semiconductor layer; And forming a source electrode and a drain electrode spaced apart from each other, wherein the step of forming the oxide semiconductor layer includes the steps of: forming a thin film for hydrogen blocking layer on the substrate; And forming a hydrogen barrier layer and an active layer by patterning the thin film for hydrogen barrier layer and the thin film for active layer, wherein the thin film for hydrogen barrier layer is formed by MOCVD, The hydrogen barrier layer may include at least one of gallium (Ga), zinc (Zn), and 5% of a mixed amount of gallium (Ga) and zinc (Zn) Including indium and provides [(In) / (Ga + Zn) ≤ 0.05], the manufacturing method of a thin film transistor having at least 5.9 cm ³ density.

(In) / (Ga + Zn) 0.03] is formed so as to include not more than 3% of indium (In) relative to the mixed amount of gallium (Ga) and zinc (Zn) .

The content ratio of gallium (Ga) and zinc (Zn) contained in the hydrogen barrier layer is 1: 2 to 5: 1 [0.5? (Ga / Zn)? 5].

The hydrogen barrier layer has a thickness of 0.5 to 3.0 nm.

The hydrogen barrier layer has a density of 6.5 g / cm &lt; ³ &gt; or less.

The method of manufacturing a thin film transistor further includes forming a first insulating film on the substrate before forming the oxide semiconductor layer.

The method of manufacturing a thin film transistor may further include forming a light blocking layer on the substrate before forming the first insulating layer, wherein the oxide semiconductor layer is formed to overlap the light blocking layer in a plan view.

The step of forming the gate electrode may be performed before or after the step of forming the oxide semiconductor layer.

According to another embodiment of the present invention, there is provided a thin film transistor including a substrate, a thin film transistor disposed on the substrate, and a first electrode connected to the thin film transistor, wherein the thin film transistor includes: an oxide semiconductor layer on the substrate; A source electrode connected to the oxide semiconductor layer, and a drain electrode spaced apart from the source electrode and connected to the oxide semiconductor layer, wherein the oxide semiconductor layer is formed of a material selected from the group consisting of hydrogen And the active layer on the hydrogen barrier layer, wherein the hydrogen barrier layer comprises gallium (Ga), zinc (Zn), indium in an amount of not more than 5% based on the mixed amount of gallium (Ga) and zinc (Zn) [(In) / (Ga + Zn)? 0.05], and has a density of 5.9 cm ³ or more.

Since the thin film transistor according to an embodiment of the present invention includes a hydrogen barrier layer having a very thin thickness and excellent hydrogen barrier properties, it has excellent stability against hydrogen penetration and can be manufactured in an ultra thin film form. According to one embodiment of the present invention, the hydrogen barrier layer is formed by deposition to have a large density, and the density of atoms in the hydrogen barrier layer is very high. Thereby, the hydrogen barrier layer can have a good hydrogen blocking ability.

The display device according to an embodiment of the present invention including such a thin film transistor has excellent reliability and can have a thin thickness.

In addition to the effects noted above, other features and advantages of the invention will be set forth hereinafter, or may be apparent to those skilled in the art to which the invention pertains from such teachings and descriptions.

1 is a cross-sectional view of a thin film transistor according to an embodiment of the present invention.
2 is a cross-sectional view of a thin film transistor according to another embodiment of the present invention.
3 is a cross-sectional view of a thin film transistor according to another embodiment of the present invention.
4 is a cross-sectional view of a thin film transistor according to another embodiment of the present invention.
5A to 5F are cross-sectional views illustrating a manufacturing process of a thin film transistor according to another embodiment of the present invention.
Figure 6 is a schematic diagram illustrating metal-organic chemical vapor deposition (MOCVD).
7 is a schematic cross-sectional view of a display device according to another embodiment of the present invention.
8 is a schematic cross-sectional view of a display device according to another embodiment of the present invention.
9 is a graph of the hydrogen content according to the depth of the sample prepared in Example 1. Fig.
10A and 10B show the results of measuring the threshold voltage (Vth) for the thin film transistors of Comparative Examples 1 and 2, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. And the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited to those shown in the drawings. Like elements throughout the specification may be referred to by like reference numerals. In the following description of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the present invention may be unnecessarily obscured.

Where the terms "comprises", "having", "comprising", and the like are used herein, other portions may be added unless the expression "only" is used. Where an element is referred to in the singular, it includes the plural unless specifically stated otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or &quot; direct &quot; is used, one or more other portions may be located between the two portions.

The terms spatially relative, "below," "lower," "above," "upper," and the like, And may be used to easily describe the correlation with other elements or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term " below " can include both downward and upward directions. Likewise, the exemplary terms " above " or " phase " can include both upward and downward directions.

In the case of a description of a temporal relationship, for example, if the temporal relationship is described by 'after', 'after', 'after', 'before', etc., May not be continuous unless they are not used.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

The terms " first horizontal axis direction ", " second horizontal axis direction ", and " vertical axis direction " should not be interpreted solely by the geometric relationship in which the relationship between them is vertical, It may mean having a wider directionality in the inside.

It should be understood that the term " at least one " includes all possible combinations from one or more related items. For example, the meaning of " at least one of the first item, the second item and the third item " means not only the first item, the second item or the third item, but also the second item and the second item among the first item, May refer to any combination of items that may be presented from more than one.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

Hereinafter, a thin film transistor, a method of manufacturing the same, and a display device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to the constituent elements of the drawings, the same constituent elements may have the same sign as possible even if they are displayed on different drawings

1 is a cross-sectional view of a thin film transistor 100 according to an embodiment of the present invention.

The thin film transistor 100 according to an embodiment of the present invention includes an oxide semiconductor layer 130 on a substrate 110 and a gate electrode 130 which is insulated from the oxide semiconductor layer 130 and overlaps with at least a part of the oxide semiconductor layer 130 A source electrode 150 connected to the oxide semiconductor layer 130 and a drain electrode 160 separated from the source electrode 150 and connected to the oxide semiconductor layer 130.

As the substrate 110, glass or plastic may be used. Transparent plastic having a flexible property as plastic, for example, polyimide, may be used.

When a polyimide is used as the substrate 110, a heat-resistant polyimide that can withstand high temperatures can be used, considering that a high-temperature deposition process is performed on the substrate 110. In this case, in order to form a thin film transistor, a process such as vapor deposition, etching, etc. may be performed in a state where the polyimide substrate is disposed on a carrier substrate made of a highly durable material such as glass.

A first insulating layer 121 is disposed on the substrate 110. The first insulating layer 121 may include at least one of silicon oxide and silicon nitride. According to an embodiment of the present invention, the first insulating layer 121 may be made of silicon oxide such as SiO ₂ .

The first insulating film 121 may be a single film or may have a laminated structure in which two or more films are stacked. The first insulating layer 121 has excellent insulating properties and planarization characteristics and can protect the oxide semiconductor layer 130. The first insulating layer 121 disposed on the substrate 110 is also referred to as a buffer layer.

Generally, the first insulating film 121 contains hydrogen (H). Hydrogen contained in the first insulating layer 121 moves to the oxide semiconductor layer 130 and bonds with oxygen in the oxide semiconductor layer 130 to cause oxygen vacancies in the oxide semiconductor layer 130, The oxide semiconductor layer 130 may be made conductive. When the hydrogen (H) contained in the first insulating layer 121 moves to the oxide semiconductor layer 130, the oxide semiconductor layer 130 is damaged and the reliability of the thin film transistor 100 is lowered.

Therefore, it is necessary to prevent the hydrogen (H) of the first insulating film 121 from moving to the oxide semiconductor layer 130. The first insulating film 121 may be omitted.

The oxide semiconductor layer 130 includes a hydrogen blocking layer 131 on the substrate 110 and an active layer 132 on the hydrogen blocking layer 131. In this case, 1, the oxide semiconductor layer 130 includes a hydrogen blocking layer 131 on the first insulating layer 121 and an active layer 132 on the hydrogen blocking layer 131.

A channel of the thin film transistor 100 is formed in the active layer 132. Therefore, the active layer 132 is referred to as a channel layer. The active layer 132 includes an oxide semiconductor material. For example, the active layer 132 may be formed of one selected from the group consisting of IZO (InZnO) based, IGO (InGaO) based, ITO (InSnO) based, IGZO based InGaZnO based, IGZTO based InGaZnSnO based, GZTO based GaZnSnO based ITZO , &Lt; / RTI &gt; and the like. However, the embodiment of the present invention is not limited thereto, and the active layer 132 may be formed by another oxide semiconductor material known in the art.

The hydrogen barrier layer 131 prevents hydrogen (H) from flowing into the active layer 132 serving as a channel layer, and protects the active layer 132. More specifically, the hydrogen blocking layer 131 serves as a barrier to hydrogen (H), blocking the entry of hydrogen into the active layer 132.

The hydrogen barrier layer 131 includes gallium (Ga) and zinc (Zn).

Gallium (Ga) forms a stable bond with oxygen and is excellent in resistance to gas penetration. Therefore, since hydrogen does not form a bond with gallium (Ga) on the surface of the hydrogen barrier layer 131, hydrogen is not diffused into the hydrogen barrier layer 131.

Zinc (Zn) contributes to stable film formation. An amorphous film or a crystalline film can be easily formed by zinc (Zn). As a result, gallium (Ga) can form a stable film together with zinc (Zn).

The hydrogen barrier layer 131 may be made of a GZO (GaZnO) based oxide semiconductor material. The GZO (GaZnO) based oxide semiconductor material is a semiconductor material mainly containing gallium (Ga) and zinc (Zn) as metal components. In addition, the hydrogen barrier layer 131 may contain a small amount of indium (In). For example, the hydrogen barrier layer 131 may include indium (In) by introducing indium (In) of the active layer 132 into the hydrogen barrier layer 131.

The hydrogen barrier layer 131 according to an embodiment of the present invention may be formed by vapor deposition. For example, the hydrogen barrier layer 131 may be formed by metal organic chemical vapor deposition (MOCVD) using an organic metal compound. The hydrogen barrier layer 131 formed by MOCVD may have a very dense and highly dense film structure.

According to one embodiment of the present invention, the hydrogen barrier layer 131 has a density of 5.9 g / cm ³ or more. If the hydrogen barrier layer 131 has a density of less than 5.9 g / cm ³ , the hydrogen blocking ability may not be excellent.

In general, it is known that a GZO (GaZnO) based oxide semiconductor material has a density of about 5.8 g / cm &lt; ^{3 &} gt ;. On the other hand, according to one embodiment of the present invention, since the hydrogen barrier layer 131 is formed by MOCVD, the hydrogen barrier layer 131 is made of a GZO-based oxide semiconductor material, And may have a density of 5.9 g / cm &lt; ³ &gt;

On the other hand, it is not easy for the GZO (GaZnO) based oxide semiconductor material to have a density exceeding 6.5 g / cm &lt; ³ &gt;. In view of this, the hydrogen barrier layer 131 according to an embodiment of the present invention may have a density of, for example, 5.9 to 6.5 g / cm &lt; ³ &gt;. More specifically, the hydrogen barrier layer 131 may have a density of, for example, from 5.9 to 6.3 g / cm &lt; ³ &gt; unless the production conditions are strictly limited beyond necessity for increasing the density.

The hydrogen barrier layer 131 according to an embodiment of the present invention has a very dense film structure and blocks hydrogen by a mechanism of blocking hydrogen rather than a mechanism of trapping hydrogen to block hydrogen. Therefore, the hydrogen barrier layer 131 need not have the same volume as the conventional hydrogen trapping layer. Therefore, the hydrogen barrier layer 131 according to an embodiment of the present invention may have a very thin thickness.

For example, the hydrogen barrier layer 131 may have a thickness of 0.5 nm to 3.0 nm. When the hydrogen barrier layer 131 has a thickness of less than 0.5 nm, the film formation is not properly performed and the hydrogen barrier function can not be sufficiently manifested. On the other hand, if the thickness of the hydrogen barrier layer 131 is more than 3.0 nm, it is disadvantageous for thinning of the device. More specifically, the hydrogen barrier layer 131 may have a thickness of 0.5 to 1.5 nm.

In the hydrogen barrier layer 131, gallium (Ga) and zinc (Zn) may have an amount of 60% or more based on the total number of atoms of the metal components. More specifically, in the hydrogen barrier layer 131, gallium (Ga) and zinc (Zn) may have an amount of 80% or more based on the total number of atoms of the total metal components. The hydrogen barrier layer 131 may contain at least 95% of gallium (Ga) and zinc (Zn) in the metal component.

The hydrogen barrier layer 131 may further include at least one of tungsten (W), chromium (Cr), molybdenum (Mo), and titanium (Ti) Tungsten (W), chromium (Cr), molybdenum (Mo), and titanium (Ti) are metals (M) having 3d orbitals and can bond with oxygen to form stable MO ₃ to remove excess oxygen. Thereby, the oxygen in the non-bonding state is reduced, and the probability of OH bonding decreases, so that hydrogen diffusion can be prevented.

When the content of the additive metal such as tungsten (W), chrome (Cr), molybdenum (Mo) and titanium (Ti) is increased, the film formation may become difficult, and the oxide semiconductor characteristic of the hydrogen barrier layer 131 It can be damaged. Such an additive metal may have an amount of 40% or less of the total metal component of the hydrogen barrier layer 131 on the basis of the number of atoms. More specifically, the additive metal may have a content of 20% or less based on the atomic number of the total metal component of the hydrogen barrier layer 131.

Alternatively, the content of tungsten (W), chromium (Cr), molybdenum (Mo) and titanium (Ti) is 20% or less of the mixed amount of gallium (Ga) and zinc (Zn) Cr + Mo + Ti) / (Ga + Zn)? 0.2].

The hydrogen barrier layer 131 according to an embodiment of the present invention may or may not include indium (In). For example, in the process of manufacturing the hydrogen barrier layer 131, indium (In) of the active layer 132 may be introduced into the hydrogen barrier layer 131 without using indium (In) (In).

When the hydrogen barrier layer 131 contains indium (In), the content of indium (In) is 5% or less [(In) / (%) of the mixed amount of gallium (Ga) Ga + Zn)? 0.05]. According to an embodiment of the present invention, the hydrogen barrier layer 131 may include indium (In) in an amount of 0 to 5% based on the mixed amount of gallium (Ga) and zinc (Zn) ? (In) / (Ga + Zn)? 0.05]. In addition, the hydrogen barrier layer 131 may contain indium (In) in an amount of more than 0 and 5% or less with respect to the mixed amount of gallium (Ga) and zinc (Zn) Ga + Zn)? 0.05].

Indium (In) is known as a component which improves the mobility of the oxide semiconductor layer and increases the charge density, and is widely used for the oxide semiconductor layer. However, since indium (In) forms a weak bond with oxygen, when hydrogen penetrates into the oxide semiconductor layer, oxygen bonded to indium (In) bonds with hydrogen instead of indium (In) O-vacancy is induced. According to an embodiment of the present invention, hydrogen can be prevented from flowing into the hydrogen barrier layer 131 by the hydrogen barrier layer 131 not containing indium (In) or containing only a small amount of indium (In) .

When indium (In) is added, the density of the oxide semiconductor layer 130 can be increased. However, according to one embodiment of the present invention, since the hydrogen barrier layer 131 is formed by evaporation without containing indium (In) or containing a small amount of indium (In), it has a density of 5.9 cm ³ or more . As described above, the hydrogen barrier layer 131 according to an embodiment of the present invention which does not contain indium (In) or contains a small amount of indium (In) and has a high density has a thickness of 3.0 nm or less It can have excellent hydrogen blocking ability.

Specifically, the hydrogen barrier layer 131 contains 5% or less of indium based on the mixed amount of gallium (Ga) and zinc (Zn) based on the atomic number [(In) / (Ga + Zn) . If the content of indium (In) exceeds 5% of the mixed amount of gallium (Ga) and zinc (Zn), oxygen penetrated into the hydrogen barrier layer 131 when indium (In) In) instead of hydrogen. As a result, an additional carrier due to O-vacancy is generated in the hydrogen barrier layer 131 and increased to the carrier concentration in the entire active layer 312, and the effect of hydrogen blocking by the hydrogen barrier layer 131 It is not sufficiently expressed.

The hydrogen barrier layer 131 may contain indium (In) of 3% or less of the mixed amount of gallium (Ga) and zinc (Zn) on the basis of the atomic number in order to more efficiently block hydrogen In) / (Ga + Zn)? 0.03]. When the content of indium (In) is 3% or less, most hydrogen is blocked by gallium (Ga) bonded to oxygen and is not transferred to the active layer 132 even if hydrogen flows into the hydrogen barrier layer 131. However, there is a possibility that the carrier concentration of the hydrogen barrier layer 131 may increase due to carriers generated while oxygen combined with a small amount of indium (In) is combined with hydrogen.

More specifically, the hydrogen barrier layer 131 may include indium (In) of 1% or less of the mixed amount of gallium (Ga) and zinc (Zn) on the basis of the atomic number [(In) / + Zn)? 0.01]. When the content of indium (In) is less than 1% of the content of gallium (Ga) and zinc (Zn), only oxygen bonded to a very small amount of indium (In) in the hydrogen barrier layer 131 bonds with hydrogen Create additional carriers. IGZO, which is mainly used as the active layer 132, generally contains 30% or more of indium (In). Therefore, the maximum value of the additional carrier concentration generated by the very small amount of indium (In) of 1% or less contained in the hydrogen barrier layer 131 is 1/30 level compared with the carriers of the entire active layer 132, Do not. However, when the active layer 132 has a low indium content, the concentration ratio of indium (In) in the hydrogen blocking layer 131 to the indium (In) concentration of the active layer 132 increases, Can be reduced.

The hydrogen barrier layer 131 may include indium (In) not more than 0.5% of the mixed amount of gallium (Ga) and zinc (Zn) on the basis of the atomic number. [(In) / (Ga + Zn) 0.005]. When the content of indium (In) relative to the mixed content of gallium (Ga) and zinc (Zn) is 0.5% or less, indium (In) - oxygen (O) bonds are substantially not generated, Ga).

According to an embodiment of the present invention, gallium (Ga) and zinc (Zn) are chemically bonded in the hydrogen barrier layer 131 that does not contain indium (In) or contains a small amount of indium (In) The arrangement of the elements is dense and the active space is not generated in the investigation blocking layer 131, so that the hydrogen blocking is efficiently performed, and the density of the film is high.

On the other hand, when the hydrogen barrier layer 131 is formed by a conventional sputtering (SPT) method, a plurality of thin film defects are present in the hydrogen barrier layer 131, thereby lowering the hydrogen blocking efficiency.

According to an embodiment of the present invention, the content ratio of gallium (Ga) and zinc (Zn) contained in the hydrogen barrier layer 131 (gallium: zinc) can be adjusted in the range of 1: 2 to 5: 0.5? (Ga / Zn)? 5]. When the ratio of gallium (Ga) to zinc (Zn) is less than 0.5, hydrogen blocking ability of the hydrogen barrier layer 131 may be lowered. On the other hand, when the ratio of gallium (Ga) to zinc (Zn) exceeds 5, the content of zinc (Zn) relative to gallium (Ga) is insufficient. For example, when the content of zinc (Zn) is insufficient in the hydrogen blocking film 131, grain boundaries or dislocations may occur between the crystal faces due to crystallization of gallium (Ga) As a result, a path may be formed in which hydrogen diffuses into the active layer 132.

More specifically, the content ratio of gallium (Ga) to zinc (Zn) can be adjusted to 1? [Ga / Zn]? 4. When the content of gallium (Ga) in the hydrogen barrier layer 131 is equal to or greater than the content of zinc (Zn), hydrogen can be effectively blocked by the combination of gallium (Ga) and oxygen. When the content ratio of gallium (Ga) to zinc (Zn) is 4 or less, the crystallization of gallium (Ga) can be limited to a certain extent by zinc (Zn), but as a result, a stable amorphous uniform thin film can be formed.

A second insulating layer 122 is disposed on the oxide semiconductor layer 130. The second insulating film 122 may include at least one of silicon oxide and silicon nitride. The second insulating film 122 may include aluminum oxide (Al ₂ O ₃ )

The second insulating film 122 may have a single film structure or a multilayer film structure. For example, the aluminum oxide layer, the silicon oxide layer, and the silicon nitride layer may independently form the second insulating film 122, or they may be stacked to form the second insulating film 122.

Referring to FIG. 1, the gate electrode 140 is disposed on the second insulating layer 122. Specifically, the gate electrode 140 is insulated from the oxide semiconductor layer 130 and overlaps with the oxide semiconductor layer 130 at least partially. As shown in FIG. 1, the structure of the thin film transistor 100 in which the gate electrode 140 is disposed on the oxide semiconductor layer 130 is also referred to as a top gate structure. The second insulating layer 122 disposed between the gate electrode 140 and the oxide semiconductor layer 130 and insulating the gate electrode 140 from the oxide semiconductor layer 130 is also referred to as a gate insulating layer

The gate electrode 140 may be formed of an aluminum-based metal such as aluminum or an aluminum alloy, a silver-based metal such as silver or silver alloy, a copper-based metal such as copper or a copper alloy, (Cr), tantalum (Ta), neodymium (Nd), and titanium (Ti), for example, molybdenum series metals such as molybdenum (Mo) or molybdenum alloy. The gate electrode 140 may have a multilayer structure including at least two conductive films having different physical properties.

An interlayer insulating film 170 is disposed on the gate electrode 140. The interlayer insulating film 170 is made of an insulating material. Specifically, the interlayer insulating layer 170 may be formed of an organic material, an inorganic material, or a laminate of an organic material layer and an inorganic material layer.

A source electrode 150 and a drain electrode 160 are disposed on the interlayer insulating film 170. The source electrode 150 and the drain electrode 160 are spaced apart from each other and connected to the oxide semiconductor layer 130, respectively. Referring to FIG. 1, a source electrode 150 and a drain electrode 160 are connected to an oxide semiconductor layer 130 through a contact hole formed in an interlayer insulating layer 170, respectively. More specifically, the source electrode 150 and the drain electrode 160 are connected to the active layer 132 of the oxide semiconductor layer 130, respectively.

The source electrode 150 and the drain electrode 160 may be formed of at least one selected from the group consisting of Mo, Al, Cr, Au, Ti, Cu), and alloys thereof. The source electrode 150 and the drain electrode 160 may be formed of a single layer made of a metal or a metal alloy, respectively, or may be formed of multiple layers of two or more layers.

The oxide semiconductor layer 130, the gate electrode 140, the source electrode 150, and the drain electrode 160 form the thin film transistor 100.

2 is a cross-sectional view of a thin film transistor 200 according to another embodiment of the present invention. Hereinafter, in order to avoid duplication, descriptions of the components already described are omitted.

The thin film transistor 200 of FIG. 2 further includes a light blocking layer 180 disposed between the substrate 110 and the first insulating layer 121, as compared with the thin film transistor 100 of FIG. The light blocking layer 180 overlaps with the oxide semiconductor layer 130.

The light blocking layer 180 blocks light incident from the outside into the oxide semiconductor layer 130 of the thin film transistor 200 and prevents the oxide semiconductor layer 130 from being damaged by external incident light.

The first insulating layer 121 is formed on the light blocking layer 180 in order to isolate the light blocking layer 180 from the oxide semiconductor layer 130. Therefore, . In this case, hydrogen contained in the first insulating layer 121 is diffused into the oxide semiconductor layer 130 to cause oxygen vacancy (O vacancy) in the oxide semiconductor layer 130, or the oxide semiconductor layer 130 is made conductive .

The thin film transistor 200 according to another embodiment of the present invention includes a hydrogen barrier layer 131 to prevent oxygen deficiency or conduction of the oxide semiconductor layer 130 by hydrogen. Specifically, the oxide semiconductor layer 130 includes a hydrogen barrier layer 131 and an active layer 132, and the hydrogen barrier layer 131 is disposed in contact with the first insulating layer 121.

3 is a cross-sectional view of a thin film transistor 300 according to another embodiment of the present invention.

3 includes a gate electrode 140 on a substrate 110, an oxide semiconductor layer 130 which is insulated from the gate electrode 140 and overlaps with at least a part of the gate electrode 130, a gate electrode 140 The source electrode 150 and the source electrode 150 connected to the oxide semiconductor layer 130 and the oxide semiconductor layer 130 are spaced apart from each other so that the first insulating layer 121, the oxide semiconductor layer 130, And a drain electrode 160.

Referring to FIG. 3, a gate electrode is disposed between the substrate 110 and the first insulating layer 121. As shown in FIG. 3, a structure in which the gate electrode 140 is disposed under the oxide semiconductor layer 130 is also referred to as a bottom gate structure. Here, the oxide semiconductor layer 130, the gate electrode 140, the source electrode 150, and the drain electrode 160 form the thin film transistor 300.

The oxide semiconductor layer 130 of FIG. 3 includes a hydrogen barrier layer 131 and an active layer 132, and the hydrogen barrier layer 131 is disposed in contact with the first insulating layer 121.

4 is a cross-sectional view of a thin film transistor 400 according to another embodiment of the present invention.

The thin film transistor 400 shown in FIG. 4 further includes an etch stopper 185 disposed on the oxide semiconductor layer 130, as compared with the thin film transistor 300 shown in FIG. The etch stopper 185 may be made of an insulating material. The etch stopper 185 can protect the channel region of the oxide semiconductor layer 130. As described above, the oxide semiconductor layer 130 according to an embodiment of the present invention can be applied to the thin film transistor 400 having the etch stopper structure.

Hereinafter, a method of manufacturing the thin film transistor 200 will be described with reference to FIGS. 5A to 5H. 5A to 5H are process diagrams illustrating a manufacturing process of the thin film transistor 200 according to an embodiment of the present invention.

Referring to FIG. 5A, a light blocking layer 180 is formed on a substrate 110.

Glass can be used as the substrate 110, and a transparent plastic that can be bent or rolled can be used. An example of the plastic used as the substrate 110 is polyimide. When the plastic is used as the substrate 110, the manufacturing process can be carried out while the substrate 110 is disposed on the carrier substrate made of a highly durable material.

The light blocking layer 180 prevents the oxide semiconductor layer 130 from being damaged by light incident from the outside. The light blocking layer 180 may be made of a material that reflects or absorbs light, for example, an electrically conductive material such as a metal.

Referring to FIG. 5B, a first insulating layer 121 is formed on a substrate 110 including a light blocking layer 180. The first insulating layer 121 may be formed of silicon oxide. For example, the first insulating film 121 may have a single film or a multilayer film structure.

Next, an oxide semiconductor layer 130 is formed on the first insulating film 121. [ The oxide semiconductor layer 130 is formed so as to overlap with the light blocking layer 180 in plan view.

5C, a thin film 131a for a hydrogen blocking layer made of an oxide semiconductor material is formed on the first insulating film 121. [ For example, the hydrogen barrier layer thin film 131a is made of a GZO (GaZnO) based oxide semiconductor material. GZO (GaZnO) based oxide semiconductor materials mainly include gallium (Ga) and zinc (Zn) as metal components. Gallium (Ga) forms a stable bond with oxygen, and has excellent resistance to gas penetration. In addition, zinc (Zn) contributes to stable film formation.

The hydrogen barrier layer thin film 131a may further include at least one of tungsten (W), chrome (Cr), molybdenum (Mo), and titanium (Ti). In the thin film 131a for a hydrogen barrier layer, gallium (Ga) and zinc (Zn) may have an amount of 60% or more based on the total number of atoms of metal components. More specifically, the gallium (Ga) and zinc (Zn) in the hydrogen barrier layer thin film 131a may have an amount of 80% or more of the total metal component based on the atomic number, and the metal component may be gallium (Ga) (Zn).

The thin film 131a for hydrogen blocking layer does not contain indium (In) or contains indium (In), it is not more than 5% of the mixed amount of gallium (Ga) and zinc (Zn) In) / (Ga + Zn)? 0.05].

The hydrogen barrier layer thin film 131a is formed by vapor deposition. By the vapor deposition, a high-density film having a small thickness and high denseness of the arrangement of components can be formed. More specifically, a thin film 131a for a hydrogen blocking layer is formed by metalorganic chemical vapor deposition (MOCVD) using an organometallic compound.

Figure 6 is a schematic diagram illustrating metal-organic chemical vapor deposition (MOCVD).

Organometallic compounds are used as deposition sources of metal organic chemical vapor deposition (MOCVD). The organometallic compound includes a metal (M) and an organic ligand (OL) combined with a metal. The organic ligand (OL) is an organic material, for example, a hydrocarbon can be used as an organic ligand (OL).

Referring to FIG. 6, the precursor organometallic compound is vaporized to form a precursor gas (Step 1). The precursor gas thus formed is deposited on the substrate 110 (Step 2). Next, when heat is applied to the substrate 110 (Step 2), the organic ligand OL is removed and a metal film or a metal oxide film is formed on the substrate 110 (Step 3). By this metal organic chemical vapor deposition (MOCVD), the arrangement of constituent elements is dense and a high density film can be formed. In particular, the film formed in the metalorganic chemical vapor deposition (MOCVD) is dense and dense compared to the film formed by sputtering. Therefore, the hydrogen barrier layer 131 formed through the metalorganic chemical vapor deposition (MOCVD) step can have a good hydrogen blocking ability.

For forming the hydrogen barrier layer thin film 131a, an organometallic compound having gallium (Ga) and an organometallic compound having zinc (Zn) may be used as the organometallic compound. A thin film 131a for a hydrogen barrier layer made of a GZO-based oxide semiconductor can be formed by an organometallic compound having gallium (Ga) and an organometallic compound having zinc (Zn).

One organometallic compound may include both gallium (Ga) and zinc (Zn). For example, a thin film 131a for a hydrogen barrier layer made of a GZO-based oxide semiconductor may be formed by an organometallic compound having gallium (Ga) and zinc (Zn).

The thin film 131a for a hydrogen barrier layer formed by metal organic chemical vapor deposition (MOCVD) may have a large density, for example, a density of 5.9 to 6.5 g / cm &lt; ³ &gt;. More specifically, the hydrogen barrier layer thin film 131a may have a density of 5.9 to 6.3 g / cm &lt; ³ &gt;. The hydrogen barrier layer 131 formed by the hydrogen barrier layer thin film 131a having such a large density can have a good hydrogen blocking ability.

The hydrogen barrier layer thin film 131a may be formed to a thickness of 0.5 to 3.0 nm. When the thickness of the hydrogen barrier layer thin film 131a is less than 0.5 nm, film formation may not be performed properly, and when it is more than 3.0 nm, it is disadvantageous in terms of thinning of the device. More specifically, the hydrogen barrier layer thin film 131a may have a thickness of 0.5 to 1.5 nm.

Referring to FIG. 5D, an active layer thin film 132a is formed on the hydrogen barrier layer thin film 131a. The thin film 132a for the active layer may be an IZO (InZnO) based oxide semiconductor material, an IGO (InGaO) based oxide semiconductor material, an ITO (InSnO) based oxide semiconductor material, an IGZO (InGaZnO) Material, a GZTO (GaZnSnO) based oxide semiconductor material, and an ITZO (InSnZnO) based oxide semiconductor material. The active layer thin film 132a may be formed by vapor deposition or sputtering.

Referring to FIG. 5E, the hydrogen barrier layer 131a and the active layer thin film 132a are patterned to form the oxide semiconductor layer 130 including the hydrogen barrier layer 131 and the active layer 132.

The hydrogen barrier layer 131 formed by the deposition and patterning may have a thickness of 0.5 to 3.0 nm and a density of 5.9 to 6.5 g / cm &lt; ³ &gt;. The hydrogen barrier layer 131 formed by the deposition may contain indium (In) or a small amount of indium (In), but may have a density of 5.9 cm ³ or more. The hydrogen barrier layer 131 having such a high density can have a good hydrogen blocking ability while having a thin thickness of 3.0 nm or less.

Referring to FIG. 5F, a second insulating layer 122 and a gate electrode 140 are formed on the oxide semiconductor layer 130. The gate electrode 140 is insulated from the oxide semiconductor layer 130 and is formed to overlap at least a part of the oxide semiconductor layer 130.

The second insulating layer 122 is formed between the gate electrode 140 and the oxide semiconductor layer 130 to isolate the gate electrode 140 from the oxide semiconductor layer 130. Therefore, the second insulating film 122 is also referred to as a gate insulating film. A method of fabricating the thin film transistor 200 according to another embodiment of the present invention includes forming a second insulating layer 122 on the oxide semiconductor layer 130.

Referring to FIG. 5G, an interlayer insulating layer 170 is formed on the gate electrode 140. The interlayer insulating layer 170 may be formed of an organic material, an inorganic material, or a laminate of an organic material layer and an inorganic material layer.

Referring to FIG. 5H, a source electrode 150 and a drain electrode 160 are formed on the interlayer insulating layer 170. FIG. The source electrode 150 and the drain electrode 160 are spaced apart from each other and connected to the oxide semiconductor layer 130, respectively. Specifically, after the interlayer insulating film 170 is etched to form at least two contact holes exposing at least a part of the oxide semiconductor layer 130, the source electrode 150 and the drain electrode 160 are formed respectively, The electrode 150 and the drain electrode 160 may be connected to the oxide semiconductor layer 130, respectively.

As a result, a thin film transistor 200 having a top gate structure in which the gate electrode 140 is disposed on the oxide semiconductor layer 130 is made, as shown in FIG. 5H.

5A to 5H show a thin film transistor having a top gate structure in which a first insulating film 121, an oxide semiconductor layer 130, a second insulating film 122 and a gate electrode 140 are sequentially formed on a substrate 110 The manufacturing process of the transistor 200 is shown, but the manufacturing method of the thin film transistor is not limited thereto. The step of forming the gate electrode 140 may be performed before or after the step of forming the oxide semiconductor layer 130.

According to another embodiment of the present invention, a gate electrode 140, a first insulating layer 121, and an oxide semiconductor layer 130 may be sequentially formed on a substrate 110. In this case, the thin film transistors 300 and 400 of the bottom gate structure as shown in FIG. 3 or 4 can be manufactured.

7 is a schematic cross-sectional view of a display device 500 according to another embodiment of the present invention.

A display device 500 according to another embodiment of the present invention includes a substrate 110, a thin film transistor 200, and an organic light emitting diode 270 connected to the thin film transistor 200.

FIG. 7 shows a display device 500 including the thin film transistor 200 of FIG. However, the present invention is not limited thereto, and the thin film transistors 100, 300 and 400 shown in FIGS. 1, 3 and 4 may be applied to the display device 500 of FIG. 7 .

Referring to FIG. 7, a display device 500 includes a substrate 110, a thin film transistor 200 disposed on the substrate 110, and a first electrode 271 connected to the thin film transistor 200. The display device 500 also includes an organic layer 272 disposed on the first electrode 271 and a second electrode 273 disposed on the organic layer 272. [

Specifically, the substrate 110 may be made of glass or plastic. A first insulating layer 121 is disposed on the substrate 110. A light blocking layer 180 is disposed between the substrate 110 and the first insulating layer 121.

The thin film transistor 200 is disposed on the first insulating film 121 on the substrate 110. The thin film transistor 200 includes an oxide semiconductor layer 130 on the first insulating layer 121, a gate electrode 140 which is insulated from the oxide semiconductor layer 130 to overlap with at least a part of the oxide semiconductor layer 130, A source electrode 150 connected to the source electrode 150 and a drain electrode 160 separated from the source electrode 150 and connected to the oxide semiconductor layer 130. The oxide semiconductor layer 130 includes a hydrogen blocking layer 131 and an active layer 132 on the hydrogen blocking layer 131. The hydrogen blocking layer 131 includes gallium (Ga) and zinc (Zn) , And a thickness of 0.5 to 3.0 nm.

Referring to FIG. 7, a second insulating layer 122 is disposed between the gate electrode 140 and the oxide semiconductor layer 130. The second insulating film 122 may also be referred to as a gate insulating film.

The planarizing film 190 is disposed on the thin film transistor 200 to planarize the upper portion of the substrate 110. The planarizing film 190 may be formed of an organic insulating material such as acrylic resin having photosensitivity, but is not limited thereto.

The first electrode 271 is disposed on the planarization film 190. The first electrode 271 is connected to the drain electrode 160 of the thin film transistor 200 through a contact hole provided in the planarization layer 190.

The bank layer 250 is disposed on the first electrode 271 and the planarizing film 190 to define a pixel region or a light emitting region. For example, the bank layer 250 can be defined by the bank layer 250 by arranging the bank layer 250 in a matrix structure in a boundary region between a plurality of pixels.

The organic layer 272 is disposed on the first electrode 271. The organic layer 272 may also be disposed on the bank layer 250. That is, the organic layer 272 may not be separated for each pixel but may be connected to each other between adjacent pixels.

The organic layer 272 includes an organic light emitting layer. The organic layer 272 may include one organic light emitting layer, and may include two organic light emitting layers stacked one above the other or an organic light emitting layer. In this organic layer 272, light having any one of red, green, and blue colors may be emitted, and white light may be emitted.

The second electrode 273 is disposed on the organic layer 272.

The first electrode 271, the organic layer 272, and the second electrode 273 may be laminated to form the organic light emitting diode 270. [ The organic light emitting diode 270 may serve as a light amount adjusting layer in the display device 500.

Although not shown, when the organic layer 272 emits white light, the individual pixels may include a color filter for filtering the white light emitted from the organic layer 272 by wavelength. A color filter is formed on the movement path of the light. In the case of the so-called bottom emission method in which the light emitted from the organic layer 272 advances toward the lower substrate 110, the color filter is disposed below the organic layer 272, A color filter is disposed on the organic layer 272 in the case of the so-called top emission method in which the light is emitted toward the upper second electrode 273.

8 is a schematic cross-sectional view of a display device 600 according to another embodiment of the present invention.

8, a display device 600 according to another embodiment of the present invention includes a substrate 110, a thin film transistor 200 disposed on the substrate 110, a first thin film transistor 200 connected to the thin film transistor 200, Electrode 381 as shown in FIG. The display device 600 also includes a liquid crystal layer 382 on the first electrode 381 and a second electrode 383 on the liquid crystal layer 382.

The liquid crystal layer 382 serves as a light amount adjusting layer. Thus, the display device 600 shown in Fig. 8 is a liquid crystal display device including the liquid crystal layer 382. Fig.

8 includes a substrate 110, a thin film transistor 200, a planarization film 190, a first electrode 381, a liquid crystal layer 382, a second electrode 383, A barrier layer 320, color filters 341 and 342, a light shielding portion 350, and an opposite substrate 310. [

The substrate 110 may be made of glass or plastic. A first insulating layer 121 is disposed on the substrate 110. A light blocking layer 180 is disposed between the substrate 110 and the first insulating layer 121.

Referring to FIG. 8, the thin film transistor 200 is disposed on the first insulating film 121 on the substrate 110. The thin film transistor 200 includes an oxide semiconductor layer 130 on the first insulating film 121, a gate electrode 140 which is insulated from the oxide semiconductor layer 130 and overlaps at least a part of the electrode of the oxide semiconductor layer 130, A source electrode 150 connected to the semiconductor layer 130 and a drain electrode 160 separated from the source electrode 150 and connected to the oxide semiconductor layer 130.

The oxide semiconductor layer 130 includes a hydrogen barrier layer 131 and an active layer 132 on the hydrogen barrier layer 131. Referring to FIG. 8, a second insulating layer 122 is disposed between the gate electrode 140 and the oxide semiconductor layer 130.

The planarizing film 190 is disposed on the thin film transistor 200 to planarize the upper portion of the substrate 110.

The first electrode 381 is disposed on the planarization film 190. The first electrode 381 is connected to the drain electrode 160 of the thin film transistor 200 through the contact hole CH provided in the planarization layer 190.

The counter substrate 310 is disposed opposite to the substrate 110.

And the light shielding portion 350 is disposed on the counter substrate 310. [ The light shielding portion 350 has a plurality of openings. The plurality of openings are arranged corresponding to the first electrode 381 which is a pixel electrode. The light shielding portion 350 shields light from the portions excluding the openings. The light shielding portion 350 is not necessarily required, and may be omitted.

The color filters 341 and 342 are disposed on the counter substrate 310 and selectively block the wavelength of light incident from the backlight unit (not shown). Specifically, the color filters 341 and 342 may be disposed in a plurality of openings defined by the light shielding portion 350. [ Each of the color filters 341 and 342 can represent any one of red, green, and blue colors. Each of the color filters 341 and 342 may represent a color other than red, green, and blue.

The barrier layer 320 may be disposed on the color filters 341 and 342 and the light-shielding portion 350. The barrier layer 320 may be omitted.

The second electrode 383 is disposed on the barrier layer 320. For example, the second electrode 383 may be positioned on the front surface of the counter substrate 310. The second electrode 383 may be formed of a transparent conductive material such as ITO or IZO.

The first electrode 381 and the second electrode 383 are opposed to each other and a liquid crystal layer 382 is disposed therebetween. The second electrode 383 applies an electric field to the liquid crystal layer 382 together with the first electrode 381.

When the opposing surfaces between the substrate 110 and the opposing substrate 310 are defined as upper surfaces of the corresponding substrates and the surfaces opposite to the upper surfaces are respectively defined as the lower surface of the substrate 110, And the polarizing plate may be disposed on the lower surface of the counter substrate 310, respectively.

Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples and Test Examples.

[Example 1]

A first insulating film 121 made of silicon oxide was formed on a substrate 110 made of glass. At this time, the first insulating film 121 was not subjected to the heat treatment, so that the first insulating film 131 included an excessive amount of hydrogen (forming a severe condition).

 On the first insulating film 121, a thin film 131a for a hydrogen blocking layer having a thickness of 1 nm was formed by metal organic chemical vapor deposition (MOCVD). A thin film for active layer 132a having a thickness of 12 nm was formed thereon by sputtering. Next, the hydrogen barrier layer 131a and the active layer thin film 132a were patterned to form the hydrogen barrier layer 131 and the active layer 132, respectively. As a result, the oxide semiconductor layer 130 including the hydrogen barrier layer 131 and the active layer 132 was produced. A sample including the oxide semiconductor layer 130 thus produced was referred to as Example 1.

In the sample of Example 1, the hydrogen barrier layer 131 is made of a GZO-based oxide semiconductor material having a ratio of gallium (Ga) to zinc (Zn) of 3: 2 on the basis of the number of atoms. The active layer 132 is made of an IGZO-based oxide semiconductor material having a ratio of indium (In) gallium (Ga) to zinc (Zn) of 1: 1: 1 on the basis of the number of atoms.

[Test Example 1] Measurement of hydrogen content

Using the sample of Example 1, the hydrogen content was measured according to the depth.

At this time, TOF-SIMS (Time of Flight Secondary Ion Mass Spectrometry) was used. TOF-SIMS is a device for analyzing the atom or analysis that forms the surface of a material by analyzing secondary ions emitted after a primary ion with a certain energy is incident on a solid surface.

Specifically, the surface was etched while applying a constant energy to the surface of the semiconductor layer according to Example 1, and the released ions were analyzed to measure the hydrogen content by depth. The result is shown in Fig.

9 is a graph of the hydrogen content according to the depth of the sample prepared in Example 1. Fig. In the graph shown in Fig. 9, the horizontal axis represents depth. In the graph of FIG. 9, a range of 0 to 12 nm corresponds to the active layer 132, a range of 12 to 13 nm corresponds to the hydrogen barrier layer 131, and a range of 13 nm or more corresponds to the thickness of the first insulating film 121 . The vertical axis represents the number of hydrogen atoms detected and corresponds to the hydrogen concentration.

9, the hydrogen concentration in the first insulating film 121 is maintained at a high level. However, in the hydrogen barrier layer 131 (in the range of 12 to 13 nm in depth), the hydrogen concentration is abruptly lowered and the active layer 132 12 nm), it can be confirmed that the hydrogen concentration is maintained at a low level. The hydrogen concentration of the active layer 132 is 1/10 of the hydrogen concentration of the first insulating film 121. From the above results, it is confirmed that the hydrogen barrier layer 131 has a good hydrogen blocking ability.

[Example 2]

A second insulating film 122 made of silicon nitride and a 100 nm-thick gate electrode 140 made of an alloy of Mo / Ti were formed on the oxide semiconductor layer 130 manufactured in the same manner as in Example 1, An interlayer insulating film 170 was formed. Next, a source electrode 150 and a drain electrode 160 having a thickness of 100 nm were formed using a Mo / Ti alloy to fabricate a thin film transistor. The thus fabricated thin film transistor was referred to as Example 2.

[Comparative Example 1]

A thin film transistor was fabricated in the same manner as in Example 2, except that the oxide semiconductor layer 130 did not include the hydrogen barrier layer 131, and this was referred to as Comparative Example 1.

[Test Example 2] Measurement of threshold voltage (Vth)

The threshold voltage (Vth) was measured for the thin film transistors of Comparative Examples 1 and 2. For measuring the threshold voltage (Vth), a drain current was measured while applying a gate voltage in the range of -20 V to +20 V. A voltage of 0.1 V and 10 V was applied between the source electrode 150 and the drain electrode 160. The results are shown in Figs. 10A and 10B.

10A and 10B show the results of measuring the threshold voltage (Vth) for the thin film transistors of Comparative Examples 1 and 2, respectively.

Referring to FIG. 10A, it can be seen that the threshold voltage (Vth) can not be measured for the thin film transistor of Comparative Example 1. When the oxide semiconductor layer 130 does not include the hydrogen barrier layer 131 under a severe condition that the first insulating layer 121 is not subjected to heat treatment and the first insulating layer 131 contains excessive hydrogen, (Comparative Example 1) can not perform the switching function. Referring to FIG. 10A, it can be confirmed that the oxide semiconductor layer 130 in the thin film transistor of Comparative Example 1 is almost completely conductive due to the diffusion of hydrogen contained in the first insulating film 131.

On the other hand, referring to FIG. 10B, in the case of the thin film transistor according to the second embodiment, although the threshold voltage Vth is shifted in the negative direction, it can be confirmed that the threshold voltage Vth exhibits a relatively good threshold voltage (Vth) characteristic . 10B, a solid line indicates a case where a voltage of 10 V is applied between the source electrode 150 and the drain electrode 160 and a solid line indicates a voltage of 0.1 V between the source electrode 150 and the drain electrode 160 .

When the oxide semiconductor layer 130 includes the hydrogen barrier layer 131 even under severe conditions in which the first insulating layer 121 is not heat-treated and the first insulating layer 131 contains excessive hydrogen, It can be confirmed that the thin film transistor including the semiconductor layer 130 (Embodiment 2) has a good switching function.

As described above, the thin film transistor according to one embodiment of the present invention has excellent reliability and driving characteristics. Also. The display device according to an embodiment of the present invention including such a thin film transistor has excellent reliability and can have a thin thickness.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be apparent to those of ordinary skill in the art. Accordingly, the scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning, scope, and equivalence of the claims are to be construed as being included within the scope of the present invention.

100, 200, 300, 400: Thin film transistor
110: substrate 121: first insulating film
122: second insulating film 130: oxide semiconductor layer
131: hydrogen barrier layer 132: active layer
140: gate electrode 150: source electrode
160: drain electrode 180: light blocking layer
185: etch stopper 190: planarization film
250: bank layer 270: organic light emitting element
271, 381: first electrode 272: organic layer
273, 383: second electrode 310: opposing substrate
341, 342: Color filter 350:
382: liquid crystal layer 500, 600: display device

Claims (17)

An oxide semiconductor layer on a substrate;
A gate electrode that is insulated from the oxide semiconductor layer and overlaps at least a part of the oxide semiconductor layer;
A source electrode connected to the oxide semiconductor layer; And
And a drain electrode spaced apart from the source electrode and connected to the oxide semiconductor layer,
Wherein the oxide semiconductor layer comprises a hydrogen barrier layer on the substrate; And an active layer on the hydrogen barrier layer,
Wherein the hydrogen barrier layer comprises gallium (Ga), zinc (Zn) and indium in an amount of 5% or less of the mixed amount of gallium (Ga) and zinc (Zn) Zn)? 0.05], and a density of 5.9 cm &lt; ³ &gt; or more. The method according to claim 1,
Wherein the hydrogen barrier layer is formed by metal organic chemical vapor deposition (MOCVD). The method according to claim 1,
Wherein the hydrogen barrier layer has a thickness of 0.5 to 3.0 nm. The method according to claim 1,
Wherein the hydrogen barrier layer comprises [(In) / (Ga + Zn) 0.03] containing indium (In) of not more than 3% based on the mixed amount of gallium (Ga) and zinc (Zn) transistor. The method according to claim 1,
Wherein a content ratio of gallium (Ga) and zinc (Zn) contained in the hydrogen barrier layer is 1: 2 to 5: 1 [0.5? (Ga / Zn)? 5]. The method according to claim 1,
Wherein the hydrogen barrier layer further comprises at least one of tungsten (W), chromium (Cr), molybdenum (Mo), and titanium (Ti). The method according to claim 1,
And a first insulating film disposed between the substrate and the oxide semiconductor layer. The method according to claim 1,
Wherein the hydrogen barrier layer has a density of 6.5 cm &lt; ³ &gt; or less. Forming an oxide semiconductor layer on the substrate;
Forming a gate electrode that is insulated from the oxide semiconductor layer and overlaps at least part of the oxide semiconductor layer; And
And forming a source electrode and a drain electrode which are connected to the oxide semiconductor layer and are spaced apart from each other,
The forming of the oxide semiconductor layer may include:
Forming a thin film for a hydrogen barrier layer on the substrate;
Forming a thin film for an active layer on the thin film for the hydrogen barrier layer; And
And patterning the thin film for hydrogen barrier layer and the thin film for active layer to form a hydrogen barrier layer and an active layer,
The thin film for a hydrogen barrier layer is formed by MOCVD (Metal Organic Chemical Vapor Deposition)
Wherein the hydrogen barrier layer contains gallium (Ga), zinc (Zn) and indium in an amount of 5% or less based on the mixed amount of gallium (Ga) and zinc (Zn) ) &Lt; / = 0.05], and has a density of 5.9 cm &lt; ³ &gt; or more. 10. The method of claim 9,
Wherein the hydrogen barrier layer comprises [(In) / (Ga + Zn) 0.03] containing indium (In) of not more than 3% based on the mixed amount of gallium (Ga) and zinc (Zn) A method of manufacturing a transistor. 10. The method of claim 9,
Wherein a content ratio of gallium (Ga) and zinc (Zn) contained in the hydrogen barrier layer is 1: 2 to 5: 1 [0.5? (Ga / Zn)? 5]. 10. The method of claim 9,
Wherein the hydrogen barrier layer has a thickness of 0.5 to 3.0 nm. 10. The method of claim 9,
Wherein the hydrogen barrier layer thin film has a density of 6.5 g / cm &lt; ³ &gt; or less. 10. The method of claim 9,
Further comprising forming a first insulating film on the substrate before forming the oxide semiconductor layer. 15. The method of claim 14,
Further comprising forming a light blocking layer on the substrate before forming the first insulating film,
Wherein the oxide semiconductor layer is formed so as to overlap with the light blocking layer in plan view. 10. The method of claim 9,
Wherein the step of forming the gate electrode is performed before or after the step of forming the oxide semiconductor layer. Board;
A thin film transistor on the substrate; And
And a first electrode connected to the thin film transistor,
The thin-
An oxide semiconductor layer on the substrate;
A gate electrode that is insulated from the oxide semiconductor layer and overlaps at least a part of the oxide semiconductor layer;
A source electrode connected to the oxide semiconductor layer; And
And a drain electrode spaced apart from the source electrode and connected to the oxide semiconductor layer,
Wherein the oxide semiconductor layer comprises a hydrogen barrier layer on the substrate; And an active layer on the hydrogen barrier layer,
Wherein the hydrogen barrier layer contains gallium (Ga), zinc (Zn) and indium in an amount of 5% or less based on the mixed amount of gallium (Ga) and zinc (Zn) ) &Lt; / = 0.05] and a density of 5.9 cm &lt; ³ &gt; or more.

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