KR102576569B1 - Preparing method of transition metal dichalcogenide - Google Patents

Abstract

This application relates to a method for producing transition metal dichalcogenides.

Description

Method for producing transition metal dichalcogenide {PREPARING METHOD OF TRANSITION METAL DICHALCOGENIDE}

This application relates to a method for producing transition metal dichalcogenides.

Graphene is a representative two-dimensional material with excellent mechanical, thermal, and electrical properties. However, graphene has fundamental limitations in its application to electronic and optical devices due to the absence of an energy bandgap.

Transition metal dichalcogenide (TMD) has recently been proposed as a two-dimensional material that can replace graphene. Transition metal dichalcogenide is a compound of a transition metal and chalcogenide and is a nanomaterial with a two-dimensional structure similar to graphene. Since its thickness is very thin, a few atomic layers, it has flexible and transparent characteristics, making it suitable for use as a flexible thin film transistor and a channel layer for implementing flexible displays.

In particular, in the case of semiconductor transition metal dichalcogenide, it has an appropriate band gap and exhibits electron mobility of hundreds of cm ² /V·s, making it suitable for application in semiconductor devices such as transistors and future flexible transistors. The device has great potential.

In addition, MoS ₂ and WS ₂ , which are the most actively studied transition metal dichalcogenides, have a direct band gap in a single layer state, so efficient light absorption can occur, making them ideal for use in light sensors, solar cells, etc. Suitable for device applications.

Exfoliation method and chemical vapor deposition method are largely used as methods for producing transition metal dichalcogenide.

The peeling method is a method of mechanically or chemically peeling a single-layer or multi-layer two-dimensional material from a single crystal mass. Unlike the above peeling method, which peels off transition metal dichalcogenide layers that maintain crystallinity from a single crystal such as natural stone, the deposition method refers to a method of synthesizing transition metal dichalcogenide on a substrate.

Since the conventional chemical vapor deposition method has a slow deposition rate, it was mainly used to deposit thin films with a thickness of 3 ㎛ or less. In order to deposit a thick film with a thickness greater than that, the concentration of the raw material in the chamber must be significantly increased. However, when a high concentration of raw material is injected into the chamber, the raw material spreads throughout the chamber and deposits on structures such as the inner wall of the chamber, causing the generation of contaminant particles.

Republic of Korea Patent No. 10-1638121 discloses a manufacturing method and manufacturing apparatus for transition metal dichalcogenide. The registered patent manufactures a transition metal dichalcogenide having a crystal structure by providing chalcogenide gas to a transition metal source and heating the transition metal source provided with the chalcogenide gas. However, the above manufacturing method can produce transition metal dichalcogenide uniformly over a large area using a chemical vapor deposition method, but since the transition metal thin film is deposited at room temperature, the size of the crystal grains is small and the electrical properties are reduced. .

Meanwhile, Republic of Korea Patent Publication No. 2013-0103913 discloses a method for manufacturing a metal chalcogenide thin film. The published patent involves forming a transition metal thin film on a substrate using a physical vapor deposition method, providing a chalcogenide gas to the substrate on which the transition metal thin film is formed, and forming a transition metal dichalcogenide by a chemical vapor deposition method. there is. However, the above manufacturing method does not disclose a configuration for controlling electrical properties by controlling the crystallinity of the transition metal thin film.

The purpose of the present application is to solve the problems of the prior art described above, and to provide a method for producing transition metal dichalcogenide that has excellent crystallinity and can realize uniform growth on a large area.

However, the technical challenges sought to be achieved by the embodiments of the present application are not limited to those described above, and other technical challenges may exist.

As a technical means for achieving the above-described technical problem, the first aspect of the present application includes forming a transition metal thin film on the substrate using physical vapor deposition while controlling the temperature of the substrate; and providing a chalcogenide source on the transition metal thin film to produce the transition metal dichalcogenide using chemical vapor deposition.

According to one embodiment of the present application, in the step of forming the transition metal thin film, the temperature of the substrate may be adjusted to 300°C to 1200°C, but is not limited thereto.

According to one embodiment of the present application, the diffusion distance of the transition metal atoms may be adjusted by adjusting the temperature of the substrate in the step of forming the transition metal thin film, but is not limited thereto.

According to one embodiment of the present application, the transition metal thin film is selected from the group consisting of molybdenum (Mo), tungsten (W), rhenium (Re), tantalum (Ta), titanium (Ti), and combinations thereof. It may include one containing a transition metal, but is not limited thereto.

According to one embodiment of the present application, the chalcogenide source may include one selected from the group consisting of sulfur (S), tellurium (Te), selenium (Se), and combinations thereof, but is limited thereto. It doesn't work.

According to one embodiment of the present application, the chalcogenide source may be in a powder or gas state, but is not limited thereto.

According to one embodiment of the present application, the transition metal dichalcogenide is MoS ₂ , MoSe ₂ , MoTe ₂ , WS ₂ , WSe ₂ , WTe ₂ , ReS ₂ , ReSe ₂ , ReTe ₂ , TaS ₂ , TaSe ₂ , TaTe ₂ , TiS ₂ , TiSe ₂ , TiTe ₂ , and combinations thereof, but are not limited thereto.

According to one embodiment of the present application, the physical vapor deposition method may be performed by a method selected from the group consisting of a sputtering method, an electron beam deposition method, a thermal evaporation method, an ion cluster beam, a pulse laser deposition method, and combinations thereof. However, it is not limited to this.

According to one embodiment of the present application, the transition metal thin film may have a thickness of 0.25 nm to 15 nm, but is not limited thereto.

According to one embodiment of the present application, the substrate is Si, SiO ₂ , Ge, GaN, AlN, GaP, InP, GaAs, SiC, Al ₂ O ₃ , LiAlO ₃ , MgO, glass, quartz, sapphire, graphite, graphene and combinations thereof, but are not limited thereto.

According to one embodiment of the present application, the step of preparing the transition metal dichalcogenide may be performed at a temperature of 500°C to 1000°C, but is not limited thereto.

According to one embodiment of the present application, the step of forming the transition metal thin film may be performed under a pressure of 5 mTorr to 15 mTorr, but is not limited thereto.

According to one embodiment of the present application, the step of preparing the transition metal dichalcogenide may be performed under a pressure of 300 mTorr to 700 mTorr, but is not limited thereto.

The above-described means of solving the problem are merely illustrative and should not be construed as intended to limit the present application. In addition to the exemplary embodiments described above, additional embodiments may be present in the drawings and detailed description of the invention.

According to the means for solving the problem of the present application described above, the method for producing transition metal dichalcogenide of the present application can easily control the thickness of the thin film using physical vapor deposition and can be uniformly deposited on a thin film of a large area.

Furthermore, when forming a transition metal thin film on a substrate, by controlling the temperature of the substrate, the diffusion distance of transition metal atoms can be adjusted to increase crystallinity and thus improve electrical properties.

In addition, the transition metal dichalcogenide produced according to the above manufacturing method can replace existing semiconductor materials and has the advantage of being applicable to various fields such as energy storage, electronic materials, biosensors, and gas sensors.

1 is a flowchart of a method for producing transition metal dichalcogenide according to an embodiment of the present application.
Figure 2 is a schematic diagram of a method for producing transition metal dichalcogenide according to an embodiment of the present application.
Figure 3 is a schematic diagram of a method for producing transition metal dichalcogenide according to an embodiment of the present application.
Figure 4 is a schematic diagram of the step of forming a transition metal thin film on a substrate using physical vapor deposition while controlling the temperature of the substrate according to an embodiment of the present application.
Figures 5 (a) and (b) are scanning electron microscope (SEM) images of transition metal thin films according to comparative examples and examples of the present application, respectively.
Figure 6 is an X-ray diffraction (XRD) graph of a transition metal thin film according to a comparative example and example of the present application.

Below, with reference to the attached drawings, embodiments of the present application will be described in detail so that those skilled in the art can easily implement them. However, the present application may be implemented in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present application in the drawings, parts that are not related to the description are omitted, and similar reference numerals are assigned to similar parts throughout the specification.

Throughout this specification, when a part is said to be “connected” to another part, this includes not only the case where it is “directly connected,” but also the case where it is “electrically connected” with another element in between. do.

Throughout this specification, when a member is said to be located “on”, “above”, “at the top”, “below”, “at the bottom”, or “at the bottom” of another member, this means that a member is located on another member. This includes not only cases where they are in contact, but also cases where another member exists between two members.

Throughout the specification of the present application, when a part is said to “include” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

Throughout the specification of the present application, when a part “includes” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

As used herein, the terms “about,” “substantially,” and the like are used to mean at or close to a numerical value when manufacturing and material tolerances inherent in the stated meaning are presented, and to aid understanding of the present application. It is used to prevent unscrupulous infringers from unfairly exploiting disclosures in which precise or absolute figures are mentioned. Additionally, throughout the specification herein, “a step of” or “a step of” does not mean “a step for.”

Throughout this specification, the term "combination thereof" included in the Markushi format expression means a mixture or combination of one or more components selected from the group consisting of the components described in the Markushi format expression, It means including one or more selected from the group consisting of.

Throughout this specification, description of “A and/or B” means “A, B, or A and B.”

Hereinafter, the method for producing transition metal dichalcogenide of the present application will be described in detail with reference to embodiments, examples, and drawings. However, the present application is not limited to these embodiments, examples, and drawings.

As a technical means for achieving the above-described technical problem, the first aspect of the present application includes forming a transition metal thin film on the substrate using physical vapor deposition while controlling the temperature of the substrate; and providing a chalcogenide source on the transition metal thin film to produce the transition metal dichalcogenide using chemical vapor deposition.

Figure 1 is a flowchart of a method for producing a transition metal dichalcogenide according to an embodiment of the present application, Figure 2 is a schematic diagram of a method for producing a transition metal dichalcogenide according to an embodiment of the present application, and Figure 3 is an embodiment of the present application This is a schematic diagram of a method for producing transition metal dichalcogenide according to an example.

Hereinafter, a method for producing the transition metal dichalcogenide will be described with reference to FIGS. 1 to 3.

First, a transition metal thin film 200 is formed on the substrate 100 using physical vapor deposition while controlling the temperature of the substrate 100 (S100).

According to one embodiment of the present application, in the step of forming the transition metal thin film 200, the temperature of the substrate 100 may be adjusted to 300°C to 1200°C, for example, the temperature of the substrate 100 may be 500°C, but is not limited thereto.

In the step of forming the transition metal thin film 200, the diffusion distance of the transition metal atoms can be adjusted by controlling the temperature of the substrate 100.

FIG. 4 is a schematic diagram of forming a transition metal thin film 200 on a substrate 100 using physical vapor deposition while controlling the temperature of the substrate 100 according to an embodiment of the present application. Referring to FIG. 4, when a transition metal is deposited by physical vapor deposition on a high temperature substrate 100 adjusted to 300°C to 1200°C, the diffusion distance of the transition metal atoms increases, thereby forming the transition metal thin film 200. As a result, the transition metal dichalcogenide 400 has high electron mobility and its usability can also be increased.

According to one embodiment of the present application, the physical vapor deposition method may be performed by a method selected from the group consisting of a sputtering method, an electron beam deposition method, a thermal evaporation method, an ion cluster beam, a pulse laser deposition method, and combinations thereof. Specifically, it may be performed by a sputtering method, but is not limited thereto.

The physical vapor deposition method is a method of depositing a material, such as a thin film to be deposited, on a substrate through evaporation or sputtering in a vacuum.

The sputtering method is a method of accelerating plasma ionized gas such as argon at a relatively low vacuum to collide with a target and ejecting atoms of the target to form a thin film on a substrate. The sputtering method has excellent deposition capabilities, the ability to maintain complex alloys, and the ability to deposit heat-resistant metals at high temperatures.

According to one embodiment of the present application, the transition metal thin film 200 is a group consisting of molybdenum (Mo), tungsten (W), rhenium (Re), tantalum (Ta), titanium (Ti), and combinations thereof. It may include one containing a transition metal selected from, and may specifically include molybdenum, but is not limited thereto.

According to one embodiment of the present application, the step of forming the transition metal thin film 200 may be performed under a pressure of 5 mTorr to 15 mTorr, and specifically, may be performed under a pressure of 7 mTorr, but is limited thereto. It doesn't work.

Next, a chalcogenide source 300 is provided on the transition metal thin film 200 to produce transition metal dichalcogenide 400 using chemical vapor deposition (S200).

The chemical vapor deposition method is a method of supplying powder or gaseous raw materials onto a substrate and forming a thin film on the substrate surface through chemical reactions such as thermal decomposition, photolysis, redox reaction, and substitution in the gas phase or on the surface of the substrate.

According to one embodiment of the present application, the chalcogenide source 300 may include one selected from the group consisting of sulfur (S), tellurium (Te), selenium (Se), and combinations thereof, , specifically, may include sulfur, but is not limited thereto.

According to one embodiment of the present application, the chalcogenide source 300 may be in a powder or gaseous state, and specifically may be in a gaseous state, but is not limited thereto.

According to one embodiment of the present application, the transition metal dichalcogenide 400 is MoS ₂ , MoSe ₂ , MoTe ₂ , WS ₂ , WSe ₂ , WTe ₂ , ReS ₂ , ReSe ₂ , ReTe ₂ , TaS ₂ , TaSe ₂ , TaTe ₂ , TiS ₂ , TiSe ₂ , TiTe ₂ , and combinations thereof, and may specifically include MoS ₂ , but are not limited thereto.

As described above, the transition metal dichalcogenide 400 is attracting attention as a two-dimensional material that can replace graphene. Since transition metal dichalcogenides, in principle, only interact two-dimensionally with their constituent atoms, the transport of carriers in transition metal dichalcogenides shows a ballistic transport pattern, which is completely different from that in conventional thin films or bulk, and from this, It may be possible to implement mobility, high speed, and low power characteristics.

In particular, the MoS ₂ (410) is a representative transition metal dichalcogenide, which has a sandwich structure in which molybdenum (Mo) is sandwiched between sulfur (S). MoS ₂ forms layers through very strong covalent bonds between atoms, while each layer has a two-dimensional layered structure with weak van der Waals bonds.

According to one embodiment of the present application, the transition metal thin film 200 may have a thickness of 0.25 nm to 15 nm, and specifically may have a thickness of 5 nm to 10 nm, but is not limited thereto. By adjusting the thickness of the transition metal thin film 200, the thickness of the transition metal dichalcogenide 400 can be adjusted.

According to one embodiment of the present application, the substrate 100 is Si, SiO ₂ , Ge, GaN, AlN, GaP, InP, GaAs, SiC, Al ₂ O ₃ , LiAlO ₃ , MgO, glass, quartz, sapphire, graphite. , graphene, and combinations thereof, and may specifically include Si, but are not limited thereto.

According to one embodiment of the present application, the step of manufacturing the transition metal dichalcogenide 400 may be performed at a temperature of 500°C to 1000°C, but is not limited thereto.

According to one embodiment of the present application, the step of manufacturing the transition metal dichalcogenide 400 may be performed under a pressure of 300 mTorr to 700 mTorr, and specifically, may be performed under a pressure of 500 mTorr. It is not limited to this.

The present invention will be described in more detail through the following examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present application.

[Example 1] Formation of transition metal thin film

After removing impurities on the silicon substrate 110 using acetone and isopropyl alcohol (IPA), molybdenum (Mo) was deposited on the silicon substrate 110 using high-temperature DC sputtering. In the deposition step, the DC power was 80 W, the temperature of the silicon substrate 110 was 500°C, the process pressure was 7 mTorr, the amount of argon (Ar) gas was 57 sccm to 60 sccm, and the process time was 30 seconds. The thickness of the molybdenum thin film 210 was formed to be 15 nm.

[Example 2] Preparation of transition metal dichalcogenide

The molybdenum thin film 210 formed in Example 1 was placed in a CVD chamber, and 100 sccm of hydrogen sulfide (H ₂ S) 310 gas was injected and heated to 750°C. At this time, the process pressure was 500 mTorr and the process time was 15 minutes. MoS ₂ (410), a transition metal dichalcogenide (400), was uniformly manufactured by uniformly and continuously supplying sulfur using the hydrogen sulfide gas (310).

[Comparative example]

In order to confirm the effect of temperature control of the substrate, which is the biggest feature of the present application, on the crystallinity of the transition metal thin film, the transition metal thin film of Comparative Example 1 was manufactured. It was manufactured in the same manner as Example 1, and the temperature of the substrate was adjusted to room temperature instead of 500°C.

[Experimental example]

Figures 5 (a) and (b) are scanning electron microscope (SEM) images of transition metal thin films according to comparative examples and examples of the present application, respectively, and the size of grains of the transition metal thin films can be confirmed and compared.

Referring to Figure 5 (a), which is a scanning electron microscope image of the transition metal thin film according to the comparative example, small crystal grains of 10 nm or less were formed in the molybdenum thin film deposited to a thickness of 15 nm on a silicon substrate, whereas in the above embodiment Referring to Figure 5(b), which is a scanning electron microscope image of the transition metal thin film according to Example 1, large crystal grains of 15 nm were formed in the molybdenum thin film deposited to a thickness of 15 nm on a silicon substrate. In (a) and (b) of FIG. 5, the thin film is formed uniformly, so it is difficult to visually check the size of the crystal grains.

Figure 6 is an

Referring to FIG. 6, it can be seen that the peak width of the transition metal thin film according to Example 1 is narrower than that of the transition metal thin film according to Comparative Example, and the size of the crystal in the X-ray diffraction pattern is the width of the peak. It's a joke. Therefore, it can be seen that the crystallinity of the transition metal thin film according to Example 1 is superior.

The description of the present application described above is for illustrative purposes, and those skilled in the art will understand that the present application can be easily modified into other specific forms without changing its technical idea or essential features. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as unitary may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present application is indicated by the claims described below rather than the detailed description above, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present application.

100: substrate
110: silicon substrate
200: Transition metal thin film
210: Mo thin film
300: Chalcogenide source
310: H ₂ S gas
400: Transition metal dichalcogenide
410: MoS ₂

Claims (13)

Forming a transition metal thin film on the substrate using physical vapor deposition while controlling the temperature of the substrate; and
Characterized by providing a chalcogenide source on the transition metal thin film and producing transition metal dichalcogenide using chemical vapor deposition,
In the step of forming the transition metal thin film, the temperature of the substrate is adjusted to 500°C to 1200°C to control the diffusion distance of the transition metal atoms,
A method for producing a transition metal dichalcogenide, characterized in that the thickness of the transition metal dichalcogenide is adjusted by adjusting the thickness of the transition metal thin film.
delete delete According to claim 1,
The transition metal thin film includes a transition metal selected from the group consisting of molybdenum (Mo), tungsten (W), rhenium (Re), tantalum (Ta), titanium (Ti), and combinations thereof, Method for producing transition metal dichalcogenide.
According to claim 1,
The method of producing a transition metal dichalcogenide, wherein the chalcogenide source includes one selected from the group consisting of sulfur (S), tellurium (Te), selenium (Se), and combinations thereof.
According to claim 1,
A method for producing a transition metal dichalcogenide, wherein the chalcogenide source is in a powder or gas state.
According to claim 1,
The transition metal dichalcogenide is MoS ₂ , MoSe ₂ , _{MoTe 2, WS 2, WSe 2, WTe 2, ReS 2, ReSe 2, ReTe 2 , TaS 2 , TaSe 2 , TaTe 2} , TiS ₂ , TiSe ₂ , TiTe ₂ , and a method for producing a transition metal dichalcogenide, comprising a method selected from the group consisting of combinations thereof.
According to claim 1,
The physical vapor deposition method is performed by a method selected from the group consisting of sputtering method, electron beam deposition method, thermal evaporation method, ion cluster beam, pulse laser deposition method, and combinations thereof. Preparation of transition metal dichalcogenide method.
According to claim 1,
A method of producing a transition metal dichalcogenide, wherein the transition metal thin film has a thickness of 0.25 nm to 15 nm.
According to claim 1,
The substrate is a group consisting of Si, SiO ₂ , Ge, GaN, AlN, GaP, InP, GaAs, SiC, Al ₂ O ₃ , LiAlO ₃ , MgO, glass, quartz, sapphire, graphite, graphene, and combinations thereof. A method for producing a transition metal dichalcogenide, comprising a method selected from.
According to claim 1,
A method for producing a transition metal dichalcogenide, wherein the step of preparing the transition metal dichalcogenide is performed at a temperature of 500°C to 1000°C.
According to claim 1,
The step of forming the transition metal thin film is performed under a pressure of 5 mTorr to 15 mTorr.
According to claim 1,
The step of preparing the transition metal dichalcogenide is performed under a pressure of 300 mTorr to 700 mTorr.