Method for forming transition metal dichalcogenide film

Abstract

This method for forming a transition metal dichalcogenide film includes a step (A), a step (B), and a step (C). In the step (A), a substrate having a plurality of different transition metal-containing films that are positioned adjacent to each other is provided. In the step (B), the substrate is annealed at a first temperature in an atmosphere of a gas containing a chalcogenation gas or an inert gas. In the step (C), after the step (B) is executed, the substrate is annealed at a second temperature that is higher than the first temperature in an atmosphere of a gas containing a chalcogenation gas.

Description

Method for forming transition metal dichalcogenide films

[0001] This disclosure relates to a method for depositing transition metal dichalcogenide films.

[0002] Patent Document 1 describes a technique for depositing a thin film of molybdenum chalcogenide or tungsten chalcogenide.

[0003] Japanese Patent Publication No. 2022-101619

[0004] This disclosure provides a technology that can form high-quality transition metal dichalcogenide films.

[0005] One embodiment of the present disclosure provides a method for forming a transition metal dichalcogenide film. This film formation method comprises steps (A), (B), and (C). Step (A) provides a substrate having a plurality of adjacent and different transition metal-containing films. Step (B) anneals the substrate at a first temperature in an atmosphere of gas containing a chalcogenizing gas. Step (C) anneals the substrate at a second temperature higher than the first temperature in an atmosphere of gas containing a chalcogenizing gas or an inert gas after step (B) has been performed.

[0006] According to one embodiment of the present disclosure, a high-quality transition metal dichalcogenide film can be formed.

[0007] FIG. 1 is a schematic cross-sectional view showing a configuration example of a substrate processing apparatus. FIG. 2 is a diagram showing an example of a flowchart of a method for forming a transition metal dichalcogenide film. FIG. 3 is a diagram showing a configuration example of a substrate in each step of the film formation method. FIG. 4 is a diagram showing another configuration example 1 of the substrate in each step of the film formation method. FIG. 5 is a diagram showing an example of temperature adjustment in steps S2 and S3 of the film formation method. FIG. 6 is a diagram showing another example of temperature adjustment in steps S2 and S3 of the film formation method. FIG. 7 is a diagram showing an example of experimental results of the layerability of the first transition metal buffer film after the first annealing treatment. FIG. 8 is a diagram showing another configuration example 2 of the substrate. FIG. 9 is a diagram showing another configuration example 3 of the substrate. FIG. 10 is a diagram showing an example of a flowchart of the manufacture of a semiconductor device. FIG. 1 is a diagram showing a configuration example of a substrate in each step of the manufacture of a semiconductor device. FIG. 12 is a diagram showing another configuration example of the substrate in each step of the manufacture of a semiconductor device.

[0008] Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. Note that the method for forming a transition metal dichalcogenide film according to the present disclosure is not limited by this embodiment, and the following embodiments can be appropriately combined within a range that does not conflict with the respective configurations and processing contents of the present disclosure. In addition, each drawing referred to below is schematic for convenience of explanation. Therefore, details may be omitted, and the dimensional ratios do not necessarily match the actual ones.

[0009] Transition metal dichalcogenides (hereinafter also referred to as "TMDC"), which are two-dimensional layered structure materials that are strong candidates for next-generation transistor channel materials and the like, have attracted attention as materials having thin and excellent electrical characteristics.

[0010] It is known that TMDC with good crystallinity is formed on the c-plane of sapphire used when directly forming TMDC by reflecting the lattice constant of the c-plane. However, since the TMDC formed on sapphire needs to be transferred to the substrate actually used, the development of transfer technology and the increase in man-hours are problems.

[0011] Further, by using hexagonal boron nitride (h-BN) which has a lattice constant close to that of TMDC and has the same hexagonal crystal structure as the underlying film of TMDC, there is a possibility of forming TMDC with excellent crystallinity. However, it is difficult to form hexagonal boron nitride (h-BN) into a film. In addition, in order to achieve both the formation of hexagonal boron nitride (h-BN) and the formation of TMDC, the formation of hexagonal boron nitride (h-BN) and the formation of TMDC need to be carried out in separate film-forming chambers from the perspective of residual gas management. Alternatively, when performing in the same film-forming chamber, a process for removing residual gases such as nitrogen and sulfur needs to be added, which complicates the device configuration and lengthens the process time until film formation is completed. In addition, although a method of directly forming TMDC on a desired substrate surface such as a silicon oxide film is known, the crystallinity is inferior to the method of forming on sapphire.

[0012] Therefore, the method for forming a transition metal dichalcogenide film according to an embodiment of the present disclosure is TiO ｘ An initial film such as a film, and Mo, MoN, MoO ｘ And MoO ｘ N ｙ A substrate W is provided in which an initial film of TMDC such as a film is adjacent. These initial films may have a structure such as amorphous. Thereafter, the present film-forming method heats the substrate W at a first temperature which is a low temperature region of the first annealing. At the relatively low first temperature, mainly an initial film such as a TiO ｘ film is chalcogenated and converted into a layered structure, and a film such as a TiS ２ film is formed. At this point, the initial film of TMDC has not been converted into a layered structure, but may be chalcogenated.

[0013] Thereafter, the present film-forming method heats the substrate W at a second temperature which is a high temperature region of the second annealing. At the second temperature, the initial film of TMDC is crystallized based on the crystal information of a film such as a TiS ２ film having a layered structure. As a result, TMDC is obtained by forming an initial film of TMDC such as Mo, MoN, MoO ｘ And MoO ｘ N ｙ film into a layered structure. As a result, TiS formed by the first annealing ２A high-quality transition metal dichalcogenide film (TMDC) in which the crystal structure and lattice constant of a film or the like are reflected is formed. In the first annealing, Mo, MoN, MoO ｘ or MoO ｘ N ｙ If the chalcogenation of the initial film of TMDC such as a film is insufficient, after chalcogenating the initial film of TMDC such as Mo, MoN, MoO ２ films on films such as TiS ｘ やMoO ｘ N ｙ films, etc., it is converted into a layered structure. Further, thereafter, by forming a gate insulating film and a gate electrode using the gap formed by removing the film such as the TiS ２ film, etc. in a subsequent process, a transistor structure of a nanosheet or a CFET can be fabricated.

[0014] FIG. 1 is a schematic cross-sectional view showing a configuration example of a substrate processing apparatus 1. The substrate processing apparatus 1 can be an apparatus for implementing a method for forming a transition metal dichalcogenide film according to an embodiment of the present disclosure.

[0015] In one embodiment, the substrate processing apparatus 1 includes a chamber 10, a substrate support portion 11, a gas introduction portion 13, an exhaust portion 14, a gas supply portion 15, a power supply 16, and a control portion 2.

[0016] The chamber 10 is configured to form a processing space 10s inside. The substrate support portion 11 is disposed inside the chamber ​​and is disposed below the processing space 10s.

[0017] In one embodiment, the substrate support portion 11 has a disk shape with a thickness in the vertical direction (up and down direction) and has a heat source 30 inside. The heat source ​​30 is, for example, a heater and is configured to generate heat by power supply from the power supply 16.

[0018] In one embodiment, the gas introduction section 13 is located above the substrate support section 11. The gas introduction section 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlet ports 13c. The gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the processing space 10s from the plurality of gas inlet ports 13c. The plurality of gas inlet ports 13c are connected to the gas supply section 15.

[0019] The gas supply unit 15 has at least one gas source 50 and at least one flow controller 51. In one embodiment, the gas supply unit 15 is configured to supply at least one processing gas to the gas introduction unit 13 from the corresponding gas source 50 via the corresponding flow controller 51. Each flow controller 51 includes, for example, a mass flow controller or a pressure-controlled flow controller. The processing gas may be a gas containing a chalcogenized gas. The chalcogenized gas contains elements such as sulfur and selenium. For example, the gas containing a chalcogenized gas may be hydrogen sulfide or a mixture of hydrogen sulfide and an inert gas.

[0020] The exhaust section 14 is connected, for example, to a gas outlet 10e located at the bottom of the chamber 10. The exhaust section 14 includes a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof. The pressure in the chamber 10 is controlled by the pressure regulating valve in conjunction with a pressure gauge 17 installed in the chamber 10 to reach a predetermined pressure.

[0021] The control unit 2 processes computer-executable instructions that cause the substrate processing apparatus 1 to perform the various processes described herein. The control unit 2 may be configured to control each element of the substrate processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the substrate processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a22, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 may be configured to perform various control operations by reading a program from the storage unit 2a22 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or it may be obtained via a medium when needed. The obtained program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 and executed. The medium may be various storage media readable by the computer 2a, or it may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the substrate processing device 1 via a communication line such as a LAN (Local Area Network).

[0022] <An Example of a Method for Deposition of a Transition Metal Dichalkogenide Film> Next, a method for depositing a transition metal dicichalkogenide film according to an embodiment of the present disclosure will be described with reference to Figure 2. Figure 2 is a diagram showing an example of a flowchart for a method for depositing a transition metal dicichalkogenide film. As shown in Figure 2, in one embodiment, the film deposition method includes a step S1 of providing a substrate W having a plurality of different transition metal-containing films, a step S2 of annealing the substrate W at a first temperature in an atmosphere of gas containing a chalcogenizing gas, and a step S3 of annealing the substrate W at a second temperature higher than the first temperature in an atmosphere of gas containing a chalcogenizing gas or an inert gas. The film deposition method may be performed by the substrate processing apparatus 1 shown in Figure 1. The control unit 2 may control each part of the substrate processing apparatus 1 to execute the film deposition method on the substrate W.

[0023] (Step S1: Provision of the substrate) In one embodiment, in step S1, as shown in Figure 1, the substrate W is provided into the chamber 10 of the substrate processing apparatus 1. Step S1 is an example of step (A). The substrate W is placed on the substrate support portion 11. The substrate W has a plurality of different transition metal-containing films located adjacent to each other.

[0024] Multiple different transition metal-containing films may have a first transition metal-containing film and a second transition metal-containing film. The transition metals contained in the first transition metal-containing film and the second transition metal-containing film are different. Figure 3 is a diagram showing an example of the configuration of the substrate W in each step of the film formation method. Figure 4 is a diagram showing another example of the configuration of the substrate W in each step of the film formation method. The substrate W shown in Figures 3(a) and 4(a) has a first transition metal-containing film 21a and a second transition metal-containing film 22a. In the substrate W shown in Figure 3(a), the first transition metal-containing film 21a is located between the substrate 20 and the second transition metal-containing film 22a. The surface of the substrate W has the second transition metal-containing film 22a exposed, and the side surface of the substrate W has both the first transition metal-containing film 21a and the second transition metal-containing film 22a exposed. As shown in Figure 4(a), the positions of the first transition metal-containing film 21a and the second transition metal-containing film 22a may be swapped. In this case, the second transition metal-containing film 22a is located between the substrate 20 and the first transition metal-containing film 21a, the surface of the substrate W is exposed to the first transition metal-containing film 21a, and the side surfaces of the substrate W are exposed to both the first transition metal-containing film 21a and the second transition metal-containing film 22a. The substrate W may be used in the manufacture of semiconductor devices. Semiconductor devices include, for example, memory devices such as DRAM and 3D-NAND flash memory, and logic devices.

[0025] The transition metal contained in the first transition metal-containing film 21a may include, but is not limited to, at least one selected from the group consisting of titanium, tin, and iron. The first transition metal-containing film 21a may be a transition metal oxide film. The first transition metal-containing film 21a may be, for example, Ti, Sn, or Fe, or TiO ｘ , SnO ｘ or FeO ｘ Yes, TiN ｘ SnN ｘ or FeN ｘ It is possible.

[0026] The second transition metal-containing film 22a is a film comprising at least one of a film composed of an elemental transition metal or a film composed of a compound of a transition metal. The transition metal contained in the second transition metal-containing film 22a may include, but is not limited to, at least one selected from the group consisting of molybdenum, tungsten, tantalum, niobium, zirconium, hafnium, titanium, vanadium, chromium, tin, and scandium. The second transition metal-containing film 22a may be a transition metal oxide film, a transition metal nitride film, or a transition metal film. For example, the second transition metal-containing film 22a may be Mo, MoO ｘ MoO ｘ N ｙ MoN ｘ These are possible.

[0027] The substrate 20 may be a silicon wafer, an organic film on a silicon wafer, a dielectric film, a metal film, a semiconductor film, etc. The substrate 20 may be a laminated film of multiple films. The substrate W may have a diameter of 150 mm or more or 300 mm or more.

[0028] Each film constituting the substrate W is formed by any method. The first transition metal-containing film 21a and the second transition metal-containing film 22a are formed by methods such as CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), MLD (Molecular Layer Deposition), PVD (Physical Vapor Deposition), and spin coating. The first transition metal-containing film 21a and the second transition metal-containing film 22a may be flat films or films with irregularities. In addition, the substrate W may have other films besides the first transition metal-containing film 21a and the second transition metal-containing film 22a.

[0029] At least a portion of the process for forming the first transition metal-containing film 21a and the second transition metal-containing film 22a on the substrate W may be performed in the chamber 10 as part of step S1. For example, the first transition metal-containing film 21a or the second transition metal-containing film 22a may be formed in step S1. Alternatively, the first transition metal-containing film 21a and the second transition metal-containing film 22a may be formed in step S1. In this case, the substrate processing apparatus 1 is equipped with the function of forming the first transition metal-containing film 21a and / or the second transition metal-containing film 22a. In one embodiment, the substrate W may be provided into the chamber 10 after all or part of the film on the substrate W has been formed in an apparatus outside the substrate processing apparatus 1.

[0030] In one embodiment, after performing step S1 in Figure 2, the substrate W may be patterned in step S1-1 to expose the sides of the first transition metal-containing film 21a and the second transition metal-containing film 22a. As will be described later, the gas containing the chalcogen element can chalcogenize the first transition metal-containing film 21a and the second transition metal-containing film 22a by penetrating and permeating from the main surface T2 of the second transition metal-containing film 22a or the main surface T1 of the first transition metal-containing film 21a, so it is not necessarily required to expose the sides of each film. Therefore, the step of patterning the substrate W in step S1-1 may be omitted.

[0031] In one embodiment, after the substrate W is provided to the substrate support 11, the temperature of the substrate support 11 or the substrate W is adjusted to a given temperature by the heat source 30. Controlling the temperature of the substrate support 11 or the substrate W to a given temperature may include setting the temperature of the heat source 30 to a given temperature or to a temperature different from the given temperature. The given temperature may be within the range of 100°C to 1100°C. The timing at which the temperature of the substrate support 11 or the substrate W begins to be controlled to a given temperature may be before or after the substrate W is placed on the substrate support 11, or it may be simultaneous. The temperature of the substrate support 11 or the substrate W is adjusted to different temperatures in step S2 and step S3.

[0032] Figure 3(b) shows the substrate W in a state where the sides of the first transition metal-containing film 21a and the second transition metal-containing film 22a are exposed by patterning. In Figure 4 and subsequent figures showing the configuration of the substrate W, the patterning process S1-1 is not shown. Also, in Figures 3, 4, 8, 9, 11, and 12, the substrate W is shown with films such as the first transition metal-containing film 21a and the second transition metal-containing film 22a stacked in the vertical direction, but each layer on the substrate W may also be arranged side by side in the horizontal direction.

[0033] (Step S2: Annealing at a first temperature) In step S2 shown in Figure 2, the substrate W is subjected to a first annealing treatment at a first temperature in an atmosphere of gas containing chalcogenized gas. Step S2 is an example of step (B). After the substrate W is provided to the substrate support 11 shown in Figure 1, or before the substrate W is provided to the substrate support 11, the temperature of the substrate W or the substrate support 11 is adjusted to a first temperature by the heat source 30. The first temperature is in the range of 100°C to 800°C and is lower than the second temperature adjusted in the next step S3.

[0034] The pressure inside the chamber 10 may be adjusted to a range of 0.1 Pa to 100 kPa. In one embodiment, the pressure inside the chamber 10 is adjusted by exhausting the chamber 10 using the exhaust unit 14.

[0035] The atmosphere inside the chamber 10 is adjusted to a gas atmosphere containing a chalcogenizing gas. The chalcogenizing gas may be a gas containing the chalcogenizing elements sulfur, selenium, or tellurium. When chalcogenization is performed with sulfur, for example, hydrogen sulfide or an organosulfur compound can be used as the chalcogenizing gas, but when chalcogenization is performed with selenium or tellurium, a gas containing those elements is used. In one embodiment, the atmosphere of the gas containing the chalcogenizing gas is adjusted, for example, by supplying a gas containing the chalcogenizing gas into the chamber 10 from the gas introduction section 13.

[0036] In step S2, the substrate W is subjected to a first annealing treatment at a first temperature in an atmosphere of gas containing chalcogenous elements such as sulfur and selenium to form the first transition metal-containing film 21a. The gas containing chalcogenous elements penetrates into each film from the sides (end faces) of the first transition metal-containing film 21a and the second transition metal-containing film 22a, and from the main surface T2 of the second transition metal-containing film 22a or the main surface T1 of the first transition metal-containing film 21a. As a result, the first transition metal-containing film 21a is chalcogenized and crystallized. At this time, crystallization includes the growth or rearrangement of crystals in the first transition metal-containing film 21a. As a result, a chalcogenized two-dimensional layered film is formed from the first transition metal-containing film 21a. This two-dimensional layered film is a nano-order two-dimensional sheet material formed on the surface of the substrate W, and will be referred to as the "first transition metal buffer film 21" below to distinguish it from the initial film, the first transition metal-containing film 21a. In the first annealing treatment, the second transition metal-containing film 22a may or may not be chalcogenized. A portion of the second transition metal-containing film 22a may be chalcogenized.

[0037] Figures 3(c) and 4(b) illustrate an example of the state of the substrate W in step S2. In Figures 3(c) and 4(b), the substrate W is heated in an atmosphere of gas containing a chalcogenizing gas such as hydrogen sulfide gas during the first annealing treatment in step S2, causing the first transition metal-containing film 21a to undergo chalcogenization and crystallization. As a result, a first transition metal buffer film 21 with a layered structure such as a hexagonal crystal system is formed from the first transition metal-containing film 21a.

[0038] The initial first transition metal-containing film 21a is not limited to an amorphous film, but may also be a crystalline film. If the first transition metal-containing film 21a is a crystalline film, in step S2, the first transition metal-containing film 21a is further crystallized and the crystals are rearranged to form a layered first transition metal buffer film 21.

[0039] (Step S3: Annealing at a second temperature) In step S3 shown in Figure 2, the substrate W is subjected to a second annealing treatment at a second temperature higher than the first temperature in an atmosphere of a gas containing chalcogenizing gas or an inert gas. Step S3 is an example of step (C). In step S3, the temperature of the substrate W or the substrate support part 11 is adjusted to a second temperature higher than the first temperature by the heat source 30. If the second transition metal-containing film 22a is not completely chalcogenized in the first annealing treatment, the second annealing treatment is performed in an atmosphere of a gas containing chalcogenizing gas. If the second transition metal-containing film 22a is completely chalcogenized in the first annealing treatment, the second annealing treatment is performed in an atmosphere of an inert gas.

[0040] Thus, in step S3, the second transition metal-containing film 22a is crystallized by the second annealing treatment of the substrate W at a second temperature higher than the first temperature in an atmosphere of a gas containing chalcogen elements such as sulfur and selenium or an inert gas. At this time, crystallization includes the growth or rearrangement of crystals in the second transition metal-containing film 22a. Therefore, the second transition metal-containing film 22a crystallizes based on the crystal information of the first transition metal buffer film 21, reflecting the crystal structure and lattice constant of the first transition metal buffer film 21. Furthermore, the second transition metal-containing film 22a crystallizes sequentially from the interface with the first transition metal buffer film 21. Through this crystallization of the second transition metal-containing film 22a, a high-quality two-dimensional layered film is formed from the second transition metal-containing film 22a that reflects the crystal information of the first transition metal buffer film 21. This two-dimensional layered film will be referred to below as the "transition metal dichalcogenide film 22" to distinguish it from the initial film, the second transition metal-containing film 22a.

[0041] The second transition metal-containing film 22a may be a film that crystallizes at a temperature higher than the crystallization temperature of the first transition metal-containing film 21a. As a result, the first transition metal buffer film 21 crystallizes mainly in the first annealing process of step S2, and the second transition metal-containing film 22a crystallizes mainly in the second annealing process of step S3 based on the crystallization information of the first transition metal buffer film 21. As a result, a high-quality transition metal dichalcogenide film 22 is formed from the second transition metal-containing film 22a based on the crystallization information of the first transition metal buffer film 21.

[0042] Figures 3(d) and 4(c) illustrate an example of the state of the substrate W in step S3. In Figures 3(d) and 4(c), the substrate W is heated in an atmosphere of a gas containing a chalcogenizing gas such as hydrogen sulfide or an inert gas during the second annealing treatment in step S3, causing the second transition metal-containing film 22a to crystallize. As a result, the crystallization of the second transition metal-containing film 22a reflects the crystal structure and lattice constant of the first transition metal buffer film 21, forming a high-quality transition metal dichalcogenide film 22 with good crystallinity.

[0043] In steps S2 and S3, the substrate W may be annealed by gradually or continuously increasing the first and second temperatures. Figure 5 shows an example of temperature adjustment in steps S2 and S3 of the film deposition method. Figure 6 shows another example of temperature adjustment in steps S2 and S3 of the film deposition method. The first temperature in step S2 and the second temperature in step S3 may be increased gradually. Figures 5(a) and 6(a) show an example of gradually increasing the first and second temperatures. Specifically, Figures 5(a) and 6(a) show an example in which the first temperature in step S2 is gradually increased to the target temperature and maintained for 10 minutes, and the second temperature in step S3 is gradually increased to the target temperature and maintained for 10 minutes. Figures 5(b) and 6(b) show an example of continuously increasing the first and second temperatures. In other words, Figures 5(b) and 6(b) show an example in which the first and second temperatures are gradually increased in steps S2 and S3, and then adjusted to be maintained for 10 minutes after reaching the target temperature. However, the temperature control in steps S2 and S3 is not limited to this. For example, the maintenance time of the second temperature in step S3 is not limited to 10 minutes, but may be in the range of 1 minute to 60 minutes. Similarly, for example, the maintenance time of the first temperature in step S2 is not limited to 10 minutes, but may be in the range of 1 minute to 60 minutes. Similarly, for example, the heating rate in steps S2 and S3 may be in the range of 1 minute to 60 minutes after reaching the set temperature.

[0044] In step S2 of Figure 6(a), the first annealing treatment is performed in the same hydrogen sulfide gas atmosphere as in step S2 of Figure 5(a). In step S3 of Figure 6(a), unlike step S3 of Figure 5(a), the second annealing treatment is performed in an argon gas atmosphere. Therefore, in step S3 of Figure 6(a), the supply of hydrogen sulfide gas is stopped, hydrogen sulfide gas is discharged from the chamber 10 by vacuuming, and argon gas is introduced. Argon gas is an example of an inert gas, but is not limited to it.

[0045] Similarly, in step S2 of Figure 6(b), the first annealing treatment is performed in the same hydrogen sulfide gas atmosphere as in step S2 of Figure 5(b). In step S3 of Figure 6(b), unlike step S3 of Figure 5(b), the second annealing treatment is performed in an argon gas atmosphere. Therefore, in step S3 of Figure 6(b), the supply of hydrogen sulfide gas is stopped, hydrogen sulfide gas is discharged from the chamber 10 by vacuuming, and argon gas is introduced. Argon gas is an example of an inert gas, but is not limited to it.

[0046] The second annealing treatment in step S3, illustrated in Figures 5(a) and (b), is suitable when the second transition metal-containing film 22a is not completely chalcogenized in the first annealing treatment in step S2. The second annealing treatment in step S3, illustrated in Figures 6(a) and (b), is suitable when the second transition metal-containing film 22a is completely chalcogenized in the first annealing treatment.

[0047] For example, if the second transition metal-containing film 22a is MoO ｘ In this case, chalcogenized MoS ２ Crystallization of the film begins at approximately 600°C. In this case, the first transition metal-containing film 21a may be a film that crystallizes at a first temperature lower than approximately 600°C. In this case, the first temperature may be within the range of 100°C to 600°C. The second transition metal-containing film 22a is a film that crystallizes at a second temperature of 600°C or higher. This crystallization includes the rearrangement of crystals. In this way, by performing two different temperature adjustments in steps S2 and S3, a high-quality transition metal dichalcogenide film 22 can be formed.

[0048] The pressure inside the chamber 10 is adjusted to, for example, a range of 0.1 Pa to 50 kPa. In one embodiment, the pressure inside the chamber 10 is adjusted by exhausting the chamber 10 with the exhaust unit 14. The pressure inside the chamber 10 may be the same as or different from the pressure inside the chamber 10 in step S2.

[0049] The atmosphere inside chamber 10 is adjusted to a gas atmosphere containing a chalcogenizing gas. The chalcogenizing gas may contain at least one of hydrogen sulfide or an organic sulfur compound. When chalcogenization is performed with sulfur, for example, hydrogen sulfide or an organic sulfur compound can be used as the chalcogenizing gas, but when chalcogenization is performed with selenium or tellurium, a gas containing those elements is used. In one embodiment, the atmosphere containing the chalcogenizing gas is adjusted, for example, by supplying a gas containing the chalcogenizing gas into chamber 10 from the gas introduction unit 13. The atmosphere inside chamber 10 may be the same as or different from the atmosphere inside chamber 10 in step S2.

[0050] The first transition metal-containing film 21a may be a film that crystallizes at a temperature lower than the temperature at which crystallization of the second transition metal-containing film 22a begins. Therefore, at the start of step S3, the crystallinity of the second transition metal-containing film 22a may be lower than that of the first transition metal buffer film 21. As a result, the second transition metal-containing film 22a crystallizes based on the crystallinity information of the first transition metal buffer film 21, thereby forming a high-quality transition metal dichalcogenide film 22.

[0051] The initial second transition metal-containing film 22a is not limited to an amorphous film, but may also be a crystalline film. If the second transition metal-containing film 22a is a crystalline film, in step S3, the second transition metal-containing film 22a is further crystallized and the crystals are rearranged to form a layered transition metal dichalcogenide film 22.

[0052] In Figure 3(d), the crystallization of the second transition metal-containing film 22a progresses from the interface between the first transition metal buffer film 21 and the second transition metal-containing film 22a toward the surface of the substrate W. In Figure 4(c), the crystallization of the second transition metal-containing film 22a progresses from the interface between the first transition metal buffer film 21 and the second transition metal-containing film 22a toward the back surface of the substrate W.

[0053] The second transition metal-containing film 22a may begin crystallizing simultaneously with the first transition metal-containing film 21a in step S2. The second transition metal-containing film 22a may crystallize to some extent in step S2. However, the crystallization of the second transition metal-containing film 22a is not promoted to the extent that it is converted into a layered structure in step S2. In this case, in step S3, the crystallization of the second transition metal-containing film 22a is promoted by heat at a second temperature higher than the first temperature. As mentioned above, crystallization includes the rearrangement of crystals. As a result, the transition metal dichalcogenide film 22 becomes a film with higher crystallinity compared to the crystallinity of the second transition metal-containing film 22a in step S2, based on the crystal information of the first transition metal buffer film 21. The transition metal dichalcogenide film 22 may be a two-dimensional material that can be peeled two-dimensionally. When the film is said to be "converted into a layered structure," it means that the initial film becomes a two-dimensional material with a two-dimensional layered structure. The transition metal dichalcogenide film 22 may be a thin film consisting of a single atomic layer or multiple atomic layers. The transition metal dichalcogenide film 22 may be a thin film with a wavelength of 10 nm or less.

[0054] After step S3 is completed, the substrate W is removed from the chamber 10 to the outside.

[0055] <Effects of the Embodiment> The method for forming a transition metal dichalcogenide film according to this embodiment includes a step S1 of providing a substrate W having a plurality of different transition metal-containing films, a step S2 of performing a first annealing treatment on the substrate W at a first temperature in an atmosphere of gas containing a chalcogenizing gas, and a step S3 of performing a second annealing treatment on the substrate W at a second temperature higher than the first temperature in an atmosphere of gas containing a chalcogenizing gas or an inert gas. In step S1, for example, the substrate W may be provided having an adjacent first transition metal-containing film 21a and a second transition metal-containing film 22a. The first transition metal-containing film 21a and the second transition metal-containing film 22a may have an amorphous structure or the like. The first transition metal-containing film 21a and the second transition metal-containing film 22a have different crystallization temperatures, and the first transition metal-containing film 21a may be a film that crystallizes more easily at a lower temperature than the second transition metal-containing film 22a.

[0056] In this film formation method, in the first annealing process of step S2, the substrate W is heated at a first temperature, which is in the low temperature range. At the relatively low first temperature, the first transition metal-containing film 21a mainly undergoes chalcogenization and crystallization, forming a first transition metal buffer film 21 that has been converted into a layered structure. At this point, the second transition metal-containing film 22a, which is the initial film of TMDC, has not been converted into a layered structure. As a result, at the relatively low first temperature, the chalcogenization and crystallization of the first transition metal-containing film 21a are promoted before the crystallization of the second transition metal-containing film 22a. In the first annealing process, the second transition metal-containing film 22a may or may not undergo chalcogenization. A portion of the second transition metal-containing film 22a may undergo chalcogenization.

[0057] Subsequently, in the second annealing process of step S3, the substrate W is heated to a second temperature, which is higher than the first temperature. At the high second temperature, the crystallization of the second transition metal-containing film 22a is promoted, and a transition metal dichalcogenide film 22 converted to a layered structure is formed. In step S3, the second transition metal-containing film 22a undergoes crystallization or crystal rearrangement based on the crystal information of the layered first transition metal buffer film 21. In this way, a high-quality transition metal dichalcogenide film 22 with good crystallinity that reflects the crystal structure and lattice constant of the first transition metal buffer film 21 can be formed from the second transition metal-containing film 22a. Furthermore, this film formation method can improve the efficiency of manufacturing costs and manufacturing time compared to transferring the transition metal dichalcogenide film 22 deposited on sapphire to the substrate W. Also, as will be described later, in the subsequent process, TiS ２ By utilizing the gaps created by removing films or other membranes, gate insulating films and gate electrodes can be formed to create transistor structures for nanosheets and CFETs.

[0058] In one embodiment, steps S2 and S3 can be performed in the same chamber. Therefore, after step S2, the substrate W is not exposed to the atmosphere, and step S3 can be carried out immediately afterward in the same chamber. This makes it possible to form a higher quality transition metal dichalcogenide film 22. In addition, the transport of the substrate W between steps S2 and S3 is unnecessary, and the processing time can be shortened.

[0059] (Example) A substrate W having a first transition metal-containing film 21a and a second transition metal-containing film 22a was subjected to the first annealing treatment in step S2 and the second annealing treatment in step S3. The first and second annealing treatments were performed under the following conditions. Furthermore, as the first transition metal-containing film 21a, TiO ｘ film, SnO ｘ Membrane, FeO ｘ membrane, ZrO ｘ Membrane, TaO ｘ membrane, MgO ｘ Membrane, NiO ｘ film, CuO ｘ A film and a Ni film were used. In addition, as the second transition metal-containing film 22a, MoO ｘ A membrane was used.

[0060] <Process S2: Conditions for the first annealing treatment> First temperature: 100°C or higher and less than 600°C Pressure: 0.1 Pa or higher and 50 kPa or lower Treatment time: 10 minutes Supply gas: Hydrogen sulfide

[0061] <Process S3: Conditions for the second annealing process> Second temperature: 600°C or higher and 1100°C or lower Pressure: 0.1 Pa or higher and 50 kPa or lower Processing time: 1 minute or more and 60 minutes or less after reaching the second temperature Supply gas: Ar

[0062] By performing the first annealing treatment and the second annealing treatment, MoS is formed on the substrate W. ２A film was formed. Figure 7 shows an example of experimental results regarding the layered nature of the first transition metal buffer film 21 after the first annealing treatment. The layered nature of the first transition metal buffer film 21 after the first annealing treatment is indicated by ○ and ×. "○" indicates that a two-dimensional layered structure was formed in the first transition metal buffer film 21 after the first annealing treatment. "×" indicates that a two-dimensional layered structure was not formed in the first transition metal buffer film 21 after the first annealing treatment.

[0063] From these results, TiO ｘ film, SnO ｘ Membrane, FeO ｘ The film, after the first annealing treatment, is treated with TiS ２ film, SnS ２ Membrane, FeS ２ A film was formed, and a layered structure was observed in the first transition metal buffer film 21. Therefore, TiO ｘ film, SnO ｘ Membrane, FeO ｘ The film was found to be suitable for the first transition metal-containing film 21a. In other words, on the substrate W, TiO ｘ film, SnO ｘ Membrane, FeO ｘ At least one of the films is positioned adjacent to the second transition metal-containing film 22a as the first transition metal-containing film 21a. This allows for the formation of a highly crystalline transition metal dichalcogenide film 22 from the second transition metal-containing film 22a, reflecting the crystal structure and lattice constant of the first transition metal-containing film 21a. Meanwhile, ZrO ｘ Membrane, TaO ｘ membrane, MgO ｘ Membrane, NiO ｘ film, CuO ｘ The Ni film did not exhibit a layered structure in the first transition metal buffer film 21 after the first annealing treatment, or the layered structure was insufficient. Therefore, it was found that these films are not suitable for the first transition metal-containing film 21a.

[0064] (Other board configuration examples) Other configuration examples 2 and 3 of the board W will be described with reference to Figures 8 and 9. Figure 8 is a diagram of other configuration example 2 of the board W. Figure 9 is a diagram of other configuration example 3 of the board W.

[0065] (Example of Substrate Configuration 2) In Configuration Example 2, the substrate W has a first transition metal-containing film 21a, a second transition metal-containing film 22a, and a third film 23. The third film 23 is a transition metal-containing film that forms layers at a temperature higher than the temperature at which the first transition metal-containing film 21a and the second transition metal-containing film 22a form layers, or a film that does not form layers. In the substrate W shown in Figure 8(a), the first transition metal-containing film 21a and the third film 23 are located between the substrate 20 and the second transition metal-containing film 22a. The surface of the substrate W has the second transition metal-containing film 22a exposed, and the side surfaces of the substrate W have the first transition metal-containing film 21a, the second transition metal-containing film 22a, and the third film 23 exposed. The third film 23 is adjacent to the substrate 20 and the first transition metal-containing film 21a, and the first transition metal-containing film 21a is located adjacent to the third film 23 and the second transition metal-containing film 22a. The second transition metal-containing film 22a is located adjacent to the first transition metal-containing film 21a and not adjacent to the third film 23.

[0066] In other words, in the example configuration 2 of the substrate W, the multiple transition metal-containing films include a third film that is different from the first transition metal-containing film 21a and the second transition metal-containing film 22a. The third film may be an amorphous film at temperatures below the second temperature.

[0067] Using the film formation method shown in Figure 2, a transition metal dichalcogenide film 22 is formed by layering the second transition metal-containing film 22a, shown in Figure 8(c), with the first transition metal buffer film 21 after the first annealing treatment shown in Figure 8(b). Subsequently, although not shown, the third film 23 that is not layered is removed by etching. This allows a desired film, such as an insulating film like a High-k film or a metal film like an electrode layer, to be embedded in the etched space.

[0068] (Example of substrate configuration 3) In configuration example 3, the substrate W has a structure in which a first transition metal-containing film 21a and a second transition metal-containing film 22a are alternately deposited. In the substrate W shown in Figure 9(a), the first transition metal-containing film 21a and the second transition metal-containing film 22a are arranged in alternating layers in this order. On the surface of the substrate W, the second transition metal-containing film 22a is exposed, and on the side surface of the substrate W, the first transition metal-containing film 21a and the second transition metal-containing film 22a are exposed in alternating layers of three each. The substrate W may also have the second transition metal-containing film 22a and the first transition metal-containing film 21a swapped and arranged in alternating layers of three each.

[0069] The timing of crystallization of the first transition metal-containing film 21a and the second transition metal-containing film 22a differs depending on the temperature. At a first temperature, the crystallization of the first transition metal-containing film 21a is promoted, but the crystallization of the second transition metal-containing film 22a is not promoted.

[0070] The substrate W shown in Figure 9(a) is subjected to a first annealing treatment in step S2 and heated to a first temperature in an atmosphere of chalcogen-containing gas. As a result, the gas containing chalcogen-containing material penetrates into the film from each side (end face) of the first transition metal-containing film 21a and the second transition metal-containing film 22a, and from the main surface T2 of the second transition metal-containing film 22a.

[0071] Of the first transition metal-containing films 21a, which are the 5th, 3rd, and 1st layers relative to the substrate 20 in Figure 9(a), the 5th layer is supplied with a gas containing a sufficient amount of chalcogen. On the other hand, since the distance from the surface of the substrate W increases in the order of the 3rd and 1st layers, the 3rd and 1st layers of the first transition metal-containing films 21a may not be supplied with a gas containing a sufficient amount of chalcogen compared to the 5th layer. In this case, a method may be adopted in which the film is patterned in advance and the gas containing chalcogen is supplied from the edge.

[0072] Therefore, while chalcogenization of the first transition metal-containing film 21a proceeds from the sides and upper layers of each layer where the supply of chalcogen elements is high, if the substrate W is heated at a temperature lower than the crystallization temperature, the first transition metal-containing film 21a will not crystallize from its initial state.

[0073] Therefore, the supply amount of gas containing chalcogen elements is controlled so that the gas containing chalcogen elements is supplied to all layers of the first transition metal-containing film 21a. Then, in step S2, the first temperature is set to a temperature that promotes the crystallization of the first transition metal-containing film 21a in each layer, but does not promote the crystallization of the second transition metal-containing film 22a in each layer. As a result, the first transition metal-containing film 21a in each layer is reliably crystallized and chalcogenized, and a multi-layered first transition metal buffer film 21 having a layered structure is formed, as shown in Figure 9(b).

[0074] In step S2, the crystallization and chalcogenization of the first transition metal-containing film 21a of each layer may be controlled by controlling the first annealing time. In this case, step S3 is started after the first annealing time has elapsed since the start of step S2.

[0075] The crystallization of the first transition metal-containing film 21a in each layer may be controlled by Raman spectroscopy. In this case, the crystallization of the first transition metal-containing film 21a in each layer is evaluated by Raman scattered light emitted in response to light incident on the substrate W. When it is determined that the first transition metal-containing film 21a in each layer has a layered structure based on the Raman scattered light, the process may proceed from step S2 to step S3, and the heating temperature of the substrate W may be adjusted to a second temperature. As a result, the second transition metal-containing film 22a in each layer is reliably crystallized and chalcogenized, and a multi-layer transition metal dichalcogenide film 22 having a layered structure is formed, as shown in Figure 9(c).

[0076] (Example using the substrate of Configuration Example 3) An example using the substrate W of Configuration Example 3 shown in Figure 9(c) will be described with reference to Figures 10 and 11. Figure 10 is a diagram showing an example of a flowchart for semiconductor device manufacturing. Figure 11 is a diagram showing an example of the configuration of the substrate W in each process of semiconductor device manufacturing. Note that steps S1 to S3 in Figure 10 are the same as steps S1 to S3 in Figure 2, so the explanation will be omitted here. As a result of executing steps S1 to S3 in Figure 10, example structure 3 of the substrate W shown in Figure 11(a) is obtained. The substrate W in Figure 11(a) has the same structure as the substrate W in Figure 9(c). Note that after executing step S1 in Figure 10, the process performed in step S1-1 in Figure 2 may also be performed.

[0077] In one embodiment, as shown in Figure 10, in step S4, after step S3 is performed, the first transition metal buffer film 21 formed from multiple layers of first transition metal-containing film 21a is removed by etching. Step S4 is an example of step (D). The substrate W shown in Figure 11(b) shows the state in which the multiple layers of first transition metal buffer film 21 have been removed by etching.

[0078] <Step S4: Etching conditions> The first transition metal buffer film 21 is easily oxidized in the atmosphere, while the transition metal dichalcogenide film 22 is not easily oxidized in the atmosphere. Therefore, for example, after oxidizing the first transition metal buffer film 21, the oxide film of the first transition metal buffer film 21 may be selectively etched against the transition metal dichalcogenide film 22.

[0079] One example of a method for etching the first transition metal buffer film 21 after oxidation is wet etching and dry etching. In wet etching, the substrate W is oxidized. ２ Atmosphere or H ２ The first transition metal buffer film 21 is exposed to an O atmosphere to oxidize it. Then, the oxide of the first transition metal buffer film 21 is treated with H ２ SO ４ , H ３ PO ４ and H ２ O ２ , H ２ Etching is performed with chemicals such as O and HF. These chemicals do not etch the transition metal dichalcogenide film 22. Alternatively, the first transition metal buffer film 21 may be directly wet-etched without oxidation. In this case as well, chemicals that do not etch the transition metal dichalcogenide film 22 are used.

[0080] In dry etching, the substrate W is O ２ Atmosphere or H ２The first transition metal buffer film 21 is oxidized by exposure to an oxygen atmosphere gas. Then, the oxide of the first transition metal buffer film 21 is etched with a gas that can etch but does not etch the transition metal dichalcogenide film 22. Alternatively, the first transition metal buffer film 21 may be directly dry-etched with HF gas or the like without oxidation. In this case as well, a gas that does not etch the transition metal dichalcogenide film 22 is used.

[0081] <Step S5: Embedding Process> In step S5 shown in Figure 10, after step S4 is performed, an insulating film or metal film is embedded in the gap left by the removal of the first transition metal buffer film 21. Step S5 is an example of step (E). The substrate W shown in Figure 11(c) shows a state in which an insulating film 24 such as a High-k film is embedded. The film embedded in the gap left by the removal of the first transition metal buffer film 21 may be a gate insulating film or a gate electrode. This makes it possible to easily fabricate sheet members with a thickness at the nanoscale and next-generation transistor structures of CFETs having multilayer channels.

[0082] (Example using the laminate of Configuration Example 2) The manufacturing of a semiconductor device using the laminate of Configuration Example 2 on a substrate W will be explained with reference to Figures 10 and 12. Figure 12 is a diagram showing other configuration examples of the substrate W in each process of semiconductor device manufacturing. Note that as a result of performing steps S1 to S3 in Figure 10, the structure of the substrate W shown in Figure 12(a) is obtained. The substrate W in Figure 12(a) has the same structure as the laminate obtained by stacking two layers each of Configuration Example 2 of the substrate W shown in Figure 8(c).

[0083] In one embodiment, as shown in Figure 10, in step S4, after step S3 is performed, the first transition metal buffer film 21 formed from multiple layers of first transition metal-containing film 21a is removed by etching. The substrate W shown in Figure 12(b) shows the state in which the multiple layers of first transition metal buffer film 21 have been removed by etching.

[0084] In step S5, after step S4 has been performed, an insulating film or metal film is embedded in the gap left by the removal of the first transition metal buffer film 21. The substrate W shown in Figure 12(c) shows the state in which an insulating film 24, such as a High-k film, has been embedded. For example, the third film 23 can be used as a reinforcing material for the adjacent transition metal dichalcogenide film 22.

[0085] Although not shown in Figure 10, the third film 23 may be removed by etching after step S5 is performed. The substrate W shown in Figure 12(d) shows the state in which the third film 23, which was used as a reinforcing material for the transition metal dichalcogenide film 22, has been removed by etching. As a result, the film embedding process S5 and subsequent steps can be performed while avoiding rupture of the two-dimensional transition metal dichalcogenide film 22 due to reinforcement by the third film 23.

[0086] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the attached claims.

[0087] Furthermore, the following additional information is disclosed with respect to the above embodiments. <Additional Information> (1) A method for forming a transition metal dichalcogenide film, comprising: (A) providing a substrate having a plurality of adjacent and different transition metal-containing films; (B) annealing the substrate at a first temperature in an atmosphere of gas containing a chalcogenizing gas; and (C) after the step of (B) has been performed, annealing the substrate at a second temperature higher than the first temperature in an atmosphere of gas containing the chalcogenizing gas or an inert gas. (2) The method for forming a transition metal dichalcogenide film according to (1), wherein in steps (B) and (C), the first temperature and the second temperature are raised stepwise or continuously to anneal the substrate. (3) The method for forming a transition metal dichalcogenide film according to (2), wherein the plurality of transition metal-containing films comprises a first transition metal-containing film and a second transition metal-containing film each containing a different transition metal, and the first transition metal-containing film is a film that crystallizes at a temperature lower than the crystallization temperature of the second transition metal-containing film. (4) The method for forming a transition metal dichalcogenide film according to any one of (1) to (3), wherein the first temperature is in the range of 100°C to 800°C and is lower than the second temperature. (5) The method for forming a transition metal dichalcogenide film according to any one of (1) to (4), wherein in step (C), the second temperature is raised to a preset target temperature and then maintained at the target temperature for a range of 1 minute to 60 minutes. (6) The method for forming a transition metal dichalcogenide film according to (3), wherein the first transition metal-containing film contains at least one selected from the group consisting of titanium, tin, and iron. (7) The method for forming a transition metal dichalcogenide film according to (6), wherein the first transition metal-containing film is a transition metal oxide film. (8) The method for forming a transition metal dichalcogenide film according to any one of (3), (6), or (7), wherein the second transition metal-containing film contains at least one selected from the group consisting of molybdenum, tungsten, tantalum, niobium, zirconium, hafnium, titanium, vanadium, chromium, tin, and scandium.(9) The method for forming a transition metal dichalcogenide film according to any one of (1) to (8), wherein the chalcogenizing gas is a gas containing the chalcogen element of sulfur, selenium, or tellurium. (10) The method for forming a transition metal dichalcogenide film according to any one of (3), (6), (7), or (8), wherein at the start of step (C), the crystallinity of the second transition metal-containing film is lower than the crystallinity of the first transition metal-containing film. (11) The method for forming a transition metal dichalcogenide film according to any one of (1) to (10), wherein step (B) and step (C) are performed in the same chamber. (12) The method for forming a transition metal dichalcogenide film according to any one of (3), (6), (7), (8), or (10), wherein the plurality of transition metal-containing films have a third film different from the first transition metal-containing film and the second transition metal-containing film. (13) A method for forming a transition metal dichalcogenide film according to any one of (3), (6), (7), (8), or (10), wherein a plurality of first transition metal-containing films and a plurality of second transition metal-containing films are alternately formed, and (D) after step (C) is performed, the plurality of first transition metal-containing films are removed by etching. (14) A method for forming a transition metal dichalcogenide film according to (13), wherein after step (D) is performed, an insulating film or a metal film is filled into the gaps where the plurality of first transition metal-containing films have been removed.

[0088] 1: Substrate processing unit 2: Control unit 10: Chamber 11: Substrate support unit 13: Gas introduction unit 14: Exhaust unit 15: Gas supply unit 16: Power supply 21: First transition metal buffer film 21a: First transition metal containing film 22: Transition metal dichalcogenide film 22a: Second transition metal containing film 23: Third film 24: Insulating film

Claims

1. A method for forming a transition metal dichalcogenide film, comprising: (A) providing a substrate having a plurality of adjacent and different transition metal-containing films; (B) annealing the substrate at a first temperature in an atmosphere of a gas containing a chalcogenizing gas; and (C) after performing step (B), annealing the substrate at a second temperature higher than the first temperature in an atmosphere of a gas containing the chalcogenizing gas or an inert gas.

2. The method for forming a transition metal dichalcogenide film according to claim 1, wherein in steps (B) and (C), the substrate is annealed by gradually or continuously increasing the first temperature and the second temperature.

3. The method for forming a transition metal dichalcogenide film according to claim 2, wherein the plurality of transition metal-containing films comprises a first transition metal-containing film and a second transition metal-containing film each containing a different transition metal, and the first transition metal-containing film is a film that crystallizes at a temperature lower than the crystallization temperature of the second transition metal-containing film.

4. The method for forming a transition metal dichalcogenide film according to claim 3, wherein the first temperature is in the range of 100°C to 800°C and is lower than the second temperature.

5. The method for forming a transition metal dichalcogenide film according to claim 2, wherein in step (C), the second temperature is raised to a preset target temperature and then maintained at the target temperature for a period of 1 minute to 60 minutes.

6. The method for forming a transition metal dichalcogenide film according to claim 3, wherein the first transition metal-containing film comprises at least one selected from the group consisting of titanium, tin, and iron.

7. The method for forming a transition metal dichalcogenide film according to claim 6, wherein the first transition metal-containing film is a transition metal oxide film.

8. The method for forming a transition metal dichalcogenide film according to claim 3, wherein the second transition metal-containing film comprises at least one selected from the group consisting of molybdenum, tungsten, tantalum, niobium, zirconium, hafnium, titanium, vanadium, chromium, tin, and scandium.

9. The method for forming a transition metal dichalcogenide film according to claim 1, wherein the chalcogenizing gas is a gas containing the chalcogenous element sulfur, selenium, or tellurium.

10. The method for forming a transition metal dichalcogenide film according to claim 3, wherein at the start of step (C), the crystallinity of the second transition metal-containing film is lower than that of the first transition metal-containing film.

11. The method for forming a transition metal dichalcogenide film according to claim 1, wherein step (B) and step (C) are performed in the same chamber.

12. The method for forming a transition metal dichalcogenide film according to claim 3, wherein the plurality of transition metal-containing films have a third film that is different from the first transition metal-containing film and the second transition metal-containing film.

13. A method for forming a transition metal dichalcogenide film according to claim 3, wherein a plurality of first transition metal-containing films and a plurality of second transition metal-containing films are formed alternately, and (D) after step (C) is performed, the plurality of first transition metal-containing films are removed by etching.

14. (E) After step (D) is performed, an insulating film or a metal film is filled into the gaps where the plurality of first transition metal-containing films have been removed, the method for forming a transition metal dichalcogenide film according to claim 13.

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