WO2018194399A1 - Thin-film transistor and method for manufacturing same - Google Patents

Abstract

A thin-film transistor according to an embodiment of the present invention may comprise: a metal monatomic layer comprising a gate electrode, a source electrode, a drain electrode, and at least one layer provided on the gate electrode; and a channel layer comprising a barrier layer contacting the metal monatomic layer.

Description

Thin film transistor, and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor and a method for manufacturing the same, and more particularly, to a thin film transistor in which a metal monoatomic layer operates as a channel layer and a method for manufacturing the same.

Recently, higher specification performance is required in hardware and software. Accordingly, studies on electronic devices having faster, larger capacity, and lower power characteristics have been actively conducted.

However, even if the existing MOSFET is miniaturized, there is a limit to miniaturization. This is because a problem due to miniaturization itself occurs. For example, as device densities on integrated circuits increase, high temperatures occur, which leads to problems that degrade device reliability.

Therefore, an approach through down scaling has fundamental limitations in achieving the characteristics of electronic devices required in the future.

The present inventors, to solve the problems of the prior art through the creative material that can be applied to the future-oriented device.

One technical problem to be solved by the present invention is to provide a thin film transistor including a metal monoatomic layer channel and a method of manufacturing the same.

Another technical problem to be solved by the present invention is to provide a thin film transistor having a high flashing ratio, and a manufacturing method thereof.

Another technical problem to be solved by the present invention is to provide a thin film transistor having a high reliability and a method of manufacturing the same.

The thin film transistor according to an exemplary embodiment of the present invention may include a gate electrode, a source electrode and a drain electrode, and a channel single layer formed on the gate electrode and a metal monolayer formed of at least one layer and a barrier layer in contact with the metal monolayer. It may be made, including.

According to an embodiment, when a gate voltage is applied to the gate electrode, a current may flow between the source electrode and the drain electrode through the channel layer.

According to an embodiment, the metal monoatomic layer may operate as a channel according to a gate voltage applied to the gate electrode.

According to an embodiment, when the metal monoatomic layer is made of tungsten, the metal monoatomic layer may be made of three or more layers and six or less layers.

According to an embodiment, the method may further include a stabilization layer directly interfacing with the metal monoatomic layer. Even when the metal monoatomic layer and the stabilization layer are combined, the metallic property of the metal monoatomic layer may be maintained.

According to one embodiment, the metal monoatomic layer has a two-dimensional layer structure, and further comprises a stabilization layer provided on the metal monoatomic layer, the stabilization layer is a structural form of a two-dimensional layer structure of the metal monoatomic layer Can be maintained.

According to one embodiment, the barrier layer may be made of an inorganic material.

According to one embodiment, the barrier layer may be made of ZnO.

In an embodiment, the barrier layer may be provided between the source electrode, the drain electrode, and the metal monoatomic layer, and the barrier layer may form a schottky barrier with the source electrode and the drain electrode.

According to an embodiment, the semiconductor device may further include a second stabilization layer provided between the source electrode, the drain electrode, and the barrier layer.

According to an embodiment, the semiconductor device may further include a gate insulating film provided on the gate electrode, and may further include a first stabilization layer provided between the gate insulating film and the metal monoatomic layer.

According to one embodiment, the source electrode and the drain electrode is provided on the gate electrode, the metal monoatomic layer is provided on the same level as the source electrode and the drain electrode, on the source electrode and the drain electrode The barrier layer may be provided.

The thin film transistor according to an exemplary embodiment of the present invention may include a metal monolayer formed of at least one layer, a barrier layer provided on the metal monoatomic layer, and a channel layer formed of a stabilization layer provided on the barrier layer.

In a method of manufacturing a thin film transistor according to an embodiment of the present invention, forming a monoatomic layer through atomic layer deposition (ALD) in a pressurized atmosphere and on the metal monoatomic layer, the Schottky Forming a barrier layer forming a barrier.

According to an embodiment, the metal monoatomic layer and the barrier layer may form a channel layer.

According to an embodiment, the forming of the metal monoatomic layer may be repeated several times so that the metal monoatomic layer has a thickness having semiconductor characteristics.

According to one embodiment, the strength of the pressure may be increased as the number of steps of forming the metal monoatomic layer increases.

According to an embodiment, the forming of the metal monoatomic layer may include providing a metal precursor gas made of a metal precursor in a sealed state in the chamber.

The thin film transistor according to an exemplary embodiment of the present invention may include a gate electrode, a source electrode and a drain electrode, and a channel single layer formed on the gate electrode and a metal monolayer formed of at least one layer and a barrier layer in contact with the metal monolayer. It may be made, including.

Accordingly, when a gate voltage is applied to the gate electrode, a current may flow between the source electrode and the drain electrode through the channel layer. That is, even if the channel layer is based on a metal material, it may provide an electric field effect.

In addition, according to one embodiment it can provide an excellent flashing ratio.

1 and 2 are diagrams for describing a thin film transistor according to an exemplary embodiment.

3 to 5 are views for explaining a method of manufacturing a thin film transistor according to an embodiment of the present invention.

6 is a diagram illustrating surface roughness according to the thickness of the metal monoatomic layer.

Figure 7 shows the experimental results for the metallicity of the metal monoatomic layer through XPS.

8 shows experimental results of FET characteristics of a thin film transistor according to an exemplary embodiment of the present invention.

9 illustrates experimental results of a Schottky barrier of a thin film transistor according to an exemplary embodiment of the present invention.

10 illustrates experimental results of stability characteristics of a thin film transistor according to an exemplary embodiment.

11 and 12 illustrate experimental results of FET characteristics in top and bottom contacts of a thin film transistor according to an exemplary embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical idea of the present invention is not limited to the exemplary embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed contents are thorough and complete, and that the spirit of the present invention can be sufficiently delivered to those skilled in the art.

In the present specification, when a component is mentioned to be on another component, it means that it may be formed directly on the other component or a third component may be interposed therebetween. In addition, in the drawings, the thicknesses of films and regions are exaggerated for effective explanation of technical contents.

In addition, in various embodiments of the present specification, terms such as first, second, and third are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another. Thus, what is referred to as a first component in one embodiment may be referred to as a second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. In addition, the term 'and / or' is used herein to include at least one of the components listed before and after.

In the specification, the singular encompasses the plural unless the context clearly indicates otherwise. In addition, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, element, or combination thereof described in the specification, and one or more other features or numbers, steps, configurations It should not be understood to exclude the possibility of the presence or the addition of elements or combinations thereof. In addition, the term "connection" is used herein to mean both indirectly connecting a plurality of components, and directly connecting.

The term “A is provided on B” herein may include not only the case where A is provided on B while directly contacting B, but also when A is not on B but provided on B. In addition, the term “A is provided on B” may include a case where A is provided below B, as well as a case where A is provided above B.

In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 and 2 are diagrams for describing a thin film transistor according to an exemplary embodiment.

According to an embodiment of the present invention, a thin film transistor using a metal-based material as an active layer may be provided. To this end, as shown in FIGS. 1 and 2, on the substrate 110, the gate electrode 120, the gate insulating layer 130, at least one metal monoatomic layer 150, the barrier layer 160, It may include at least one of the source electrode 180 and the drain electrode 190. Hereinafter, each configuration will be described in detail.

The substrate 110 may be made of any material on which the thin film transistor 100 may be formed. For example, the substrate 110 may be a rigid substrate or a flexible substrate.

The gate electrode 120 may have a configuration in which a gate voltage is applied to the thin film transistor 100. To this end, the gate electrode 120 may be made of a metal material.

The gate insulating layer 130 may be located on the gate electrode 120. In this case, the gate insulating layer 130 may directly contact the gate electrode 120. The gate insulating layer 130 may be, for example, Al 2 O 3. The material of the gate insulating layer 130 is not limited thereto.

At least one metal monoatomic layer 150 may be positioned on the gate insulating layer 130. The metal monoatomic layer 150 may directly contact or may not be in contact with the gate insulating layer 130.

The metal monoatomic layer 150 may be made of a metal having a two-dimensional (2D) layer structure, for example, a metal of Group 4, Group 5, or Group 6. More specifically, the metal constituting the metal monoatomic layer is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg may be made of at least one metal.

The metal monoatomic layer 150 may have a predetermined thickness having semiconductivity. If the thickness of the metal monoatomic layer 150 is thinner than a predetermined reference, it has an insulator property, and if it is thicker than a predetermined reference, it has a bulk metal property. That is, according to an exemplary embodiment of the present invention, the semiconductor property may be provided by controlling the number of layers of the metal monoatomic layer 150.

For example, when the metal monoatomic layer 150 is made of tungsten, a predetermined thickness, for example, less than three layers, may have a non-conductive property, and more than six layers may have a conductive property. Accordingly, the metal monoatomic layer 150 may have a thickness of three to six layers. In another aspect, when the metal monoatomic layer 150 is made of tungsten, it may have a thickness of 1 nm or more and 2 nm or less.

The barrier layer 160 may be formed on the metal monoatomic layer 150. For example, the barrier layer 160 may be provided on the metal monoatomic layer 150 while in direct contact with the metal monoatomic layer 150.

The barrier layer 160 may form a schottky barrier between the source electrode 180 and the drain electrode 190, which will be described later. To this end, the barrier layer 160 may be made of an inorganic material, for example, ZnO.

The source electrode 180 and the drain electrode 190 may be provided on the barrier layer 160. The source electrode 180 and the drain electrode 190 may directly contact or may not contact the barrier layer 160. In another aspect, the barrier layer 160 may be provided between the source electrode 180 and the drain electrode 190 and the metal monoatomic layer 150.

In contrast, the metal monoatomic layer 150 is provided at the same level as the source electrode 180 and the drain electrode 190, and the barrier layer 160 is the metal monoatomic layer 150 and the source electrode ( 180 may be provided to directly contact the drain electrode 190.

The metal monoatomic layer 150 and the barrier layer 160 may form a channel layer. That is, when a gate voltage is applied to the gate electrode 120, current flows between the source electrode 180 and the drain electrode 190 through a channel layer formed of the metal monoatomic layer 150 and the barrier layer 160. Can be. That is, the metal monoatomic layer 150 may operate as a channel according to the gate voltage applied to the gate electrode 120.

It may further include a stabilization layer according to an embodiment. The stabilization layer may perform a function of stabilizing the two-dimensional layered structure of the metal monoatomic layer. That is, the metal monoatomic layer has an instability such as aggregation of the monoatomic layer due to the high reactivity of the metal, but the layered structure of the metal monoatomic layer can be maintained by the introduction of the stabilization layer.

The first and second stabilization layers 140 and 170 may be formed of an organic layer. For example, the first and second stabilization layers 140 and 170 may be made of at least one of BDT and 4MP, and materials of the first and second stabilization layers 140 and 170 may be limited thereto. It is not.

The stabilization layer may include at least one of the first stabilization layer 140 and the second stabilization layer 170. The first stabilization layer 140 may be provided on one surface of the metal monoatomic layer 150, and the second stabilization layer 170 may be provided on the other surface of the metal monoatomic layer 150. In another aspect, the metal monoatomic layer 150 may have a structure sandwiched by the first and second stabilization layers 140 and 170.

In this case, the metal monoatomic layer 150 may directly contact at least one of the first and second stabilization layers 140 and 170. For example, the metal monoatomic layer 150 may be in direct contact with the first stabilization layer 140, as shown in FIGS. 1 and 2. In this case, the second stabilization layer 170 may be provided between the barrier layer 160, the source electrode 180, and the drain electrode 190.

At this time, the metal property of the metal monoatomic layer according to X-ray photoelectron spectroscopy (XPS) analysis may be maintained even when the metal monoatomic layer and the organic molecular layer are combined. This means that even if the metal constituting the metal monoatomic layer is tungsten and the tungsten layer is bonded to the binding molecules of the organic molecular layer, the oxidation state due to chemical bonding between them is not generated, and the metallicity of tungsten is maintained.

The thin film transistor according to the exemplary embodiment of the present invention has been described above with reference to FIGS. 1 and 2. Hereinafter, a thin film transistor manufacturing method according to an exemplary embodiment of the present invention will be described with reference to FIGS. 3 to 5.

3 to 5 are views for explaining a method of manufacturing a thin film transistor according to an embodiment of the present invention.

Referring to FIG. 3, in the method of manufacturing a thin film transistor according to an exemplary embodiment of the present disclosure, in the pressurized atmosphere, forming a monoatomic layer through atomic layer deposition (ALD) (S110) and the metal On the monoatomic layer, the method may include forming a barrier layer (S120).

Before performing step S110, steps S102, S104, and S106 shown in FIG. 4 may be performed.

Step S102

In step S102, the substrate may be prepared. For example, a glass substrate can be prepared.

Step S104

In step S104, a gate insulating film may be formed. The gate insulating film may be performed by a known deposition method. As a result, a gate insulating layer may be provided on the gate electrode.

Step S106

In step S106, a first stabilization layer may be formed on the gate insulating layer. The first stabilization layer may be formed by, for example, molecular layer deposition (MLD). The molecular layer growth method may refer to a vapor deposition method in which organic molecules can be controlled in molecular units through self-controlled surface reactions.

For example, when 4MP (4-Mercaptophenol) is formed as the first stabilization layer, 4MP may be used as a precursor and argon may be used as a purging gas. At this time, the pressure of the step of dosing the 4MP precursor may be 200mTorr, 20 seconds, the step of purging 60 seconds, the pressure of each process may be 100 degrees.

Step S110

Referring back to step S110 of FIG. 3, a metal monoatomic layer may be formed on the first stabilization layer. The metal monoatomic layer may be formed by an atomic layer growth method. The atomic layer growth method is a technique of depositing a monoatomic layer by using a self-control reaction in the atomic unit can enable the deposition of a monoatomic layer using a chemical adsorption and desorption process on the surface of the substrate.

Step S110 is a process for forming at least one metal monoatomic layer, and specifically includes a unit cycle consisting of dosing a metal precursor, purging, dosing a reactant, and purging. can do. One unit metal layer may be formed by a unit cycle. That is, as the unit cycle is repeated, the number of layers of the metal monoatomic layer deposited may be controlled.

In the step of dosing the metal precursor, the metal precursor may be selected according to the metal monoatomic layer to be deposited. For example, when the tungsten metal monoatomic layer is to be deposited, the metal precursor gas may be made of tungsten hexafluoride (WF ₆ ). In addition, when the molybdenum metal monoatomic layer is to be deposited, the metal precursor gas may be made of molybdenum hexafluoride (MoF ₆ ).

In the purging step, an inert gas may be used, and the inert gas may be made of, for example, argon (Ar) or nitrogen (N 2) gas. By purging, excess metal precursor that has not adsorbed to the surface of the substrate can be removed.

In the step of dosing the reactant, the reactant may be made of a material for reducing the metal precursor gas to the metal. For example, when the metal precursor is tungsten hexafluoride (WF ₆ ) or molybdenum hexafluoride (MoF ₆ ), the reaction gas may be made of disilane (Si ₂ H ₆ ).

Purging may be further performed after dosing the reactant. As a result, the excess feed gas which is not adsorbed on the surface of the substrate can be removed and the metal monoatomic layer can be formed.

By repeating the unit cycle consisting of the step of dosing, purging, dosing the reactant, purging the metal precursor described above, a multi-layered metal monoatomic layer can be formed.

According to one embodiment, the dosing the metal precursor may be performed in a pressurized atmosphere. In other words, dosing the metal precursor may be performed in an atmosphere of high pressure,

At this time, when the number of dosing the metal precursor is increased, the pressure may be the same or in particular gradually increased. This may be abbreviated as a pressurized dosing step. For convenience of description, the pressure dosing step of the metal precursor is described above, but pressure dosing may also be performed in the step of dosing the reactant.

The pressurized dosing step according to an embodiment may be performed in a sealed state in the chamber in which the substrate is provided. For example, by supplying a metal precursor into the chamber with the outlet valve of the chamber closed, it is possible to induce the inside of the chamber to a high pressure and maintain the induced high pressure. By maintaining the high pressure for a predetermined time, the metal precursor gas can be induced to be adsorbed to the target surface in a high pressure atmosphere.

According to one embodiment, in the pressure dosing step, it may be preferable that the pressure in the chamber is maintained at 0.3 Torr to 100 Torr. If the pressure in the chamber is lower than 0.3 Torr, the adsorption rate of the metal precursor is significantly lowered. However, if the pressure in the chamber is greater than 100 Torr, the substrate surface may be damaged. Therefore, in the pressure dosing step, the pressure range in the chamber may be formed from 0.3 Torr to 100 Torr, which is a high pressure. Thus, the metal precursor can be adsorbed on the substrate surface.

In addition, each of the sub-steps of step S110 may be performed at the same temperature with each other, in particular, may be performed at a low temperature. Low temperature as used herein means 200 degrees or less, preferably 100 degrees or more and 200 degrees or less. In general, agglomeration may occur because of the high reactivity of the metal monoatomic layer. Therefore, by keeping the temperature of the process at a low temperature of 100 degrees or more and 200 degrees or less, the aggregation phenomenon of the metal monoatomic layer can be prevented.

As a result, the metal monoatomic layer may be deposited on the first stabilization layer by step S110, and may be more effectively deposited by pressure dosing.

Step S120

3, the barrier layer may be deposited on the metal monolayer in step S120. For example, the barrier layer may also be deposited by the atomic layer growth method. When ZnO is used as the barrier layer, the ZnO layer may be deposited by dosing DEZ for 2 seconds at 30 mTorr pressure, dosing 20 seconds, dosing H 2 O at 30 mTorr pressure for 2 seconds, and purging for 20 seconds. At this time, the atomic layer growth method of depositing ZnO may also be performed at a temperature of 100 degrees.

As a result, a barrier layer may be formed on the metal monoatomic layer.

Step S122

Referring to FIG. 5, a second stabilization layer may be formed on the barrier layer. The second stabilization layer may be formed by a molecular layer growth method. For example, the second stabilization layer may be made of the same material as the first stabilization layer. In this case, step S122 may be the same as step S106 described above.

As a result, a second stabilization layer may be formed on the barrier layer.

Step S124

A source electrode and a drain electrode may be formed on the second stabilization layer. The source electrode and the drain electrode may be deposited by a known method.

According to the exemplary embodiment described with reference to FIGS. 3 to 5, the thin film transistor according to the exemplary embodiment described with reference to FIGS. 1 and 2 may be manufactured.

Hereinafter, performance characteristics of a thin film transistor according to an exemplary embodiment of the present invention will be described with reference to FIGS. 6 to 12.

In order to test the performance characteristics, a gate insulating film made of Al ₂ O ₃ was formed on the gate electrode. On the gate insulating film, 4 MP was deposited as the first stabilization layer through the molecular layer growth method.

Specifically, the pressure of dosing the 4MP precursor was 200 mTorr, 20 seconds, the purging step was 60 seconds, the pressure of each process was 100 degrees.

 A tungsten metal monoatomic layer was deposited on the first stabilization layer through a pressurized atomic layer growth method.

More specifically, the process conditions of the pressurized atomic layer growth method are summarized in Table 1 and Table 2 below.

WF ₆ P WF ₆ P WF ₆ P WF ₆ P WF ₆ P Time 30 s 30 s 30 s 30 s 30 s 30 s 30 s 30 s 30 s 30 s Pressure 1.0Torr 1.5Torr 2.0Torr 2.5Torr 3.0Torr

Si ₂ H ₆ P Si ₂ H ₆ P Si ₂ H ₆ P Si ₂ H ₆ P Si ₂ H ₆ P Time 30 s 30 s 30 s 30 s 30 s 30 s 30 s 30 s 30 s 30 s Pressure 1.0Torr 1.5Torr 2.0Torr 2.5Torr 3.0Torr

At this time, the number of layers of the tungsten metal monoatomic layer was controlled through the number of unit cycles. In particular, as described in Tables 1 and 2, the strength of the pressurization was increased as the number of steps of forming the metal monoatomic layer increased. In addition, while forming the tungsten metal monoatomic layer, a WF ₆ precursor gas was provided while being sealed in the chamber.

A barrier layer was formed on the metal monoatomic layer. The barrier layer was deposited by atomic layer growth, and deposited ZnO layer by dosing DEZ for 2 seconds at 30 mTorr pressure, dosing 20 seconds, dosing H ₂ O at 30 mTorr pressure for 2 seconds, and purging for 20 seconds. It was. At this time, the atomic layer growth method of depositing ZnO was also performed at a temperature of 100 degrees. As a result, a barrier layer of 1 nm could be deposited.

A second stabilization layer was formed on the barrier layer in the same manner as the first stabilization layer, and a source electrode and a drain electrode were formed on the second stabilization layer.

6 is a diagram illustrating surface roughness according to the thickness of the metal monoatomic layer.

In the case of the left side of FIG. 6, the tungsten metal monoatomic layer is deposited in three layers, in the middle of FIG. 6, in the case of four layers, and in the right side of FIG. 6, the layer is deposited in five layers.

As shown, when the tungsten metal monoatomic layer is deposited in three to five layers having semiconductor characteristics, it can be seen that the surface roughness is substantially low. This means that despite the instability of the tungsten metal monoatomic layer itself, a stable state in which aggregation does not occur is maintained. In other words, it can be seen that the first and second stabilization layers made of 4MP maintain the 2D layered structure of the tungsten metal monoatomic layer.

Figure 7 shows the experimental results for the metallicity of the metal monoatomic layer through XPS.

Referring to FIG. 7, although the metal monoatomic layer interfaces with the first stabilization layer made of the organic molecular layer and the barrier layer made of the inorganic layer, it may be confirmed that the metal monolayer is kept metallic.

8 shows experimental results of FET characteristics of a thin film transistor according to an exemplary embodiment of the present invention.

The experimental results shown in FIG. 8 are summarized in Table 3 below.

Tungsten Metal Monolayer Thickness On / Off ratio Turn on voltage 0.7 nm N / A N / A 1nm 1.06X10 ^ 3 3 V 1.3 nm 5.81X10 ^ 3 2.25V 1.6 nm 2.21X10 ^ 5 0 V 2nm 2.41X10 ^ 6 -3.5V 4 nm N / A N / A

8 and Table FET characteristics test results, when the thickness of the tungsten metal monoatomic layer is less than 1nm, that is, less than two layers, it is possible to confirm the characteristics of the insulator. In contrast, when the thickness of the tungsten metal monoatomic layer is more than 2 nm, that is, more than 7 layers, the characteristics of the conductor can be confirmed. In contrast, when the thickness of the metal monoatomic layer is 1 nm to 2 nm, that is, 3 to 6 layers, it was confirmed that there is an electric field effect.

Furthermore, when the thickness of the tungsten metal monoatomic layer was 2 nm, the on / off ratio was 2.41 × 10 6.

In addition, it can be seen that the on / off ratio and turn on voltage control are possible through the thickness control of the tungsten metal monolayer.

In the conventional case, the field effect of the metal monoatomic layer alone or the inorganic layer alone did not appear, but the FET characteristics appeared due to the synergistic effect of the metal monoatomic layer and the barrier layer.

9 illustrates experimental results of a Schottky barrier of a thin film transistor according to an exemplary embodiment of the present invention.

In order to confirm the Schottky barrier, the transfer characteristics of the transistor elements were measured in the temperature range of 320 to 350 K. The measured transfer characteristics were measured using the Richardson equation to measure the Schottky barrier between the source and drain electrodes and the ZnO barrier layer. As a result, it was confirmed that there is a Schottky barrier of 0.6 eV.

That is, by the Schottky barrier by the barrier layer, it can be interpreted that the off current in the transfer curve shown in FIG. 8 can be measured as low as 10 ^ -11 to 10 ^ -12 A.

Therefore, unlike the channel layer composed of the metal monoatomic layer alone, the channel layer composed of the metal monoatomic layer and the barrier layer can form a Schottky barrier, and thus can be interpreted as providing excellent on / off ratio characteristics. Can be.

10 illustrates experimental results of stability characteristics of a thin film transistor according to an exemplary embodiment.

In order to test the stability characteristics, the thickness of the tungsten metal monoatomic layer was 1.6 nm, and the rest of the structure was the same. As a result, the FET characteristics of the thin film transistor according to the exemplary embodiment of the present invention were found to be excellent despite the passage of time.

11 and 12 illustrate experimental results of FET characteristics in top and bottom contacts of a thin film transistor according to an exemplary embodiment of the present invention. For reference, in FIGS. 11 and 12, the first and second stabilization layers are omitted and illustrated, but the first and second stabilization layers were formed in the test sample.

In detail, FIG. 11 illustrates a channel layer according to an embodiment of the present invention in a bottom gate top contact structure, and FIG. 12 illustrates a channel layer according to an embodiment of the present invention in a bottom gate bottom contact structure.

In any of the structures shown in FIGS. 11 and 12, it can be seen that the channel layer according to the embodiment of the present invention exhibits FET characteristics.

The channel layer according to the embodiment of the present invention described above may be formed of a metal monoatomic layer and a barrier layer. The metal monoatomic layer can be formed to be conformal and have high surface coverage by high pressure dosing of the metal precursor. An inorganic material layer serving as a barrier layer may be formed on the metal monoatomic layer. Through the synergy effect of the metal monoatomic layer and the barrier layer, it is possible to provide the characteristics of the high flashing ratio due to the electric field effect.

Conventional methods used to deposit metal thin films in the vapor phase include PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition). However, in the case of a general metal thin film manufactured by the conventional method, there is no band gap and no electric field effect is exhibited due to the property of having a high charge concentration. Therefore, it could not be used as an active layer in field effect transistors, but only as an electrode. In addition, inorganic thin films exhibiting semiconductor characteristics may also be manufactured by various physical and chemical methods, but may be driven only at a specific thickness or more.

According to the development of technology, the development of ultra-high density and ultra-fine devices, and the development of binary or multi-level devices based on this requires a very thin and uniform active layer, but there are no materials available. In particular, in the multilevel device having the vertically integrated structure of the active layer, the thickness of the active layer is a very important factor due to the shielding effect of the electric field, and it is very difficult to find a material satisfying the active layer.

However, it was confirmed that the FET characteristic, which did not appear only in the metal monoatomic layer, appeared in the channel layer composed of the inorganic layer and the metal monoatomic layer according to an embodiment of the present invention. In other words, it was confirmed that the synergistic effect of the two materials, the inorganic layer and the metal monoatomic layer, provided the FET characteristics and high flashing ratio. Therefore, the thin film transistor according to the exemplary embodiment of the present invention may use a metal-based material that has not been previously driven as an active layer. Accordingly, an element made of an ultra thin film may be enabled.

As mentioned above, although this invention was demonstrated in detail using the preferable embodiment, the scope of the present invention is not limited to a specific embodiment, Comprising: It should be interpreted by the attached Claim. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

Claims (18)

A gate electrode, a source electrode and a drain electrode; And And a channel layer including a metal layer formed of at least one layer on the gate electrode, and a channel layer formed in contact with the metal monolayer. According to claim 1, And a gate voltage is applied to the gate electrode, wherein a current flows between the source electrode and the drain electrode through the channel layer. According to claim 1, And the metal monoatomic layer operates as a channel according to a gate voltage applied to the gate electrode. The method of claim 3, wherein When the metal monoatomic layer is made of tungsten, the metal monoatomic layer is made of three or more layers and six or less layers. According to claim 1, Further comprising a stabilization layer directly interfacing with the metal monoatomic layer, The metal property of the metal monoatomic layer is maintained even when the metal monoatomic layer and the stabilization layer are bonded to each other. According to claim 1, The metal monoatomic layer has a two-dimensional layered structure, Further comprising a stabilization layer provided on the metal monoatomic layer, And the stabilization layer maintains the structural form of the two-dimensional layered structure of the metal monoatomic layer. According to claim 1, The barrier layer is made of an inorganic material, a thin film transistor. The method of claim 7, wherein And the barrier layer is made of ZnO. According to claim 1, The barrier layer is provided between the source electrode and the drain electrode and the metal monoatomic layer, And the barrier layer forms a schottky barrier with the source electrode and the drain electrode. The method of claim 9, And a second stabilization layer provided between the source electrode and the drain electrode and the barrier layer. The method of claim 10, Further comprising a gate insulating film provided on the gate electrode, And a first stabilization layer provided between the gate insulating film and the metal monolayer. According to claim 1, The source electrode and the drain electrode are provided on the gate electrode, The metal monoatomic layer is provided at the same level as the source electrode and the drain electrode, The thin film transistor provided with the barrier layer on the source electrode and the drain electrode. And a channel layer including a metal monolayer formed of at least one layer, a barrier layer provided on the metal monoatomic layer, and a stabilization layer provided on the barrier layer. Forming a metal monoatomic layer through an atomic layer growth method (ALD) in a pressurized atmosphere; And Forming a barrier layer on the metal monoatomic layer to form a schottky barrier. The method of claim 14, And the metal monoatomic layer and the barrier layer form a channel layer. The method of claim 15, The forming of the metal monoatomic layer is repeated several times so that the metal monoatomic layer has a thickness having semiconductor characteristics. The method of claim 15, The strength of the pressurization increases as the number of steps of forming the metal monoatomic layer increases. The method of claim 14, The forming of the metal monoatomic layer may include providing a metal precursor gas made of a metal precursor in a sealed state in the chamber.

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