WO2016175096A1

WO2016175096A1 - Manufacturing method and manufacturing device of template substrate

Info

Publication number: WO2016175096A1
Application number: PCT/JP2016/062478
Authority: WO
Inventors: 石橋　啓次; 健一郎高橋; 鈴木　摂; 知京　豊裕
Original assignee: 国立研究開発法人物質・材料研究機構; 株式会社コメット
Priority date: 2015-04-27
Filing date: 2016-04-20
Publication date: 2016-11-03
Also published as: JPWO2016175096A1; JP6458332B2

Abstract

The purpose of the present invention is to stably and continuously manufacture template substrates with good reproducibility by sputtering, the template substrates being metal sulfide thin films epitaxially grown on an Si(100) single crystal substrate. A barrier film 2 of metal sulfide is formed on an Si(100) single crystal substrate 1 by sputtering using a target having the composition of the metal sulfide. Then, the Si(100) single crystal substrate 1 is heated and the formed barrier film 2 is crystallized by solid phase epitaxial growth to be transformed into a barrier film 3. With the Si(100) single crystal substrate 1 kept heated, an epitaxial film 4 of the metal sulfide is epitaxially grown on the crystallized barrier film 3 by sputtering using the target having the composition of the metal sulfide.

Description

Template substrate manufacturing method and manufacturing apparatus

The present invention includes high-intensity blue light-emitting elements (light-emitting diodes and semiconductor lasers), insulated gate field-effect transistors (MISFETs: Metal Insulator Semiconductors, Semiconductors, Semiconductors, Semiconductors), high-electron mobility transistors (HEMTs), and others. The present invention relates to a template substrate manufacturing method and a manufacturing apparatus suitable for use in an electronic device.

Nitride, oxide and sulfide show various physical properties. Even if they are polycrystalline, they are useful functional materials, but if they are single crystals, they have higher performance or characteristics that are manifested by making them into single crystals. Even when these materials are applied to thin film elements, it is possible to form high-performance and high-function elements that cannot be obtained with a polycrystalline thin film by forming a single crystal thin film.

For example, high-intensity blue light emitting devices using gallium nitride (GaN) thin film, MISFET using aluminum nitride / gallium nitride (AlN / GaN) thin film, HEMT using aluminum gallium nitride / gallium nitride (AlGaN / GaN) thin film, etc. Many devices using nitride thin films have been proposed and realized. However, if the nitride thin film is not a single-crystal thin film with few lattice defects and grain boundaries, the mobility of carriers is reduced, the luminous efficiency of the light emitting layer The lifetime of the thin film element is deteriorated.

These single crystal thin films are generally grown epitaxially using a single crystal substrate. In the case of a GaN-based material, a metal organic chemical vapor deposition method (MOCVD) or a gas source MBE method (Molecular Beam Epitaxic Method) is reported on a single crystal sapphire substrate. In addition, there is a report of forming on a silicon carbide (SiC) substrate by a reduced pressure metal organic chemical vapor deposition method. For oxides, sputtering or PLD (pulsed laser deposition) on single crystal strontium titanate (SrTiO ₃ : STO), single crystal lanthanum aluminate (LaAlO ₃ : LAO), single crystal sapphire substrate, etc. Thus, an epitaxial thin film is obtained.

However, these sapphire substrates, SiC substrates, single crystal STO substrates, single crystal LAO substrates and the like are expensive, so it is desirable to form them on a general-purpose Si substrate, particularly the most used Si (100) substrate. Also, from the viewpoint of integration with Si devices, it is desired to epitaxially grow a functional thin film on Si. However, it is difficult to epitaxially grow an ion-bonding thin film directly on a Si single crystal substrate. The reason for this is that Si is a covalent crystal, and a material having a lattice constant different from that of Si by several percent does not grow coherently on the substrate, resulting in lattice defects.

As a method for forming a thin film on a Si single crystal substrate, there is a method through a buffer layer. Often used is an amorphous silicon oxide formed by forming an oxide of a metal that is more easily oxidized than Si, such as cerium oxide (CeO ₂ ), yttrium oxide (Y ₂ O ₃ ), and zirconium oxide (ZrO ₂ ). This is a method for preventing the formation of SiO ₂ ). However, oxidation of the Si surface is inevitable, and there is a problem that the film quality of the buffer layer formed on SiO ₂ is not very good. In addition, a buffer layer using titanium nitride (TiN) or tantalum nitride (TaN) is also not good at forming silicon nitride (SiN _x ).

On the other hand, a method using a metal sulfide thin film for the buffer layer has been proposed (see Patent Document 1). According to Patent Document 1, the Gibbs energy generated to produce Si sulfide is relatively small, and when Si and the lattice constant are close, it is possible to epitaxially grow sulfide without forming an amorphous layer at the buffer layer / Si interface. Become. In Patent Document 1, elements having higher Gibbs energy to produce sulfide than Si include Al, Ba, Be, Ca, Ce, In, La, Li, Mg, Mn, Mo, Na, Sr, Ta, and Zr. There is a disclosure that it is possible to suppress the Si interface reaction by using sulfides of these alone or in combination thereof, and an oxide thin film element using the metal sulfide layer as a buffer layer and the oxide thin film element Manufacturing methods have been proposed. Cadmium sulfide (CdS) and zinc sulfide (ZnS) also have a higher Gibbs energy for producing sulfides than Si. Furthermore, it has been found that a sulfide thin film other than ZnS can be epitaxially grown on a Si substrate, and an ion crystal can be epitaxially grown thereon other than an oxide, and a metal sulfide epitaxial thin film is formed directly on the Si substrate. A thin film element formed and a method of manufacturing a thin film element for forming the epitaxial thin film have been proposed (see Patent Document 2 and Patent Document 3).

Japanese Patent Laid-Open No. 2002-3297 Japanese Patent Application Laid-Open No. 2004-111883 Japanese Patent Laid-Open No. 2006-344982

Patent Document 2 and Patent Document 3 disclose the formation of an epitaxial thin film of metal sulfide on a Si (100) substrate by the PLD method. However, the PLD method is difficult to form a film on a large area substrate, and is mass-productive. There is a problem. In contrast to the PLD method, the sputtering method is a thin film forming method excellent in mass productivity that can be easily formed on a large-area substrate. Patent Document 1 discloses the formation of an epitaxial thin film of metal sulfide on a Si substrate by this sputtering method. In Patent Document 1, an RCA-cleaned Si substrate is placed in a chamber of a sputtering film forming apparatus, heated to 850 ° C., and then lowered to 600 ° C. to epitaxially grow a metal sulfide thin film.

However, when the present inventors formed a thin film of metal sulfide on the Si substrate by the method described in Patent Document 1, the film was formed when sputtering film formation on a plurality of Si substrates was sequentially repeated in the same chamber. It has been found that the crystallinity of the metal sulfide thin film gradually deteriorates, leading to a state where epitaxial growth cannot be performed. Thus, it has been found that the conventional technology has problems in reproducibility and productivity (mass productivity).

In view of such problems, an object of the present invention is to provide a method and apparatus capable of stably and continuously producing a template substrate obtained by epitaxially growing a metal sulfide thin film on a Si (100) single crystal substrate by sputtering. Is to provide.

Measures for solving such problems will be described below, but other problems and novel features will become apparent from the description of the present specification and the accompanying drawings.

The present invention is a method for producing a template substrate in which a metal sulfide epitaxial film is laminated on a Si (100) single crystal substrate, and includes the following first to third steps.

In the first step, the metal sulfide barrier film is formed on the Si (100) single crystal substrate by sputtering using a target having a metal sulfide composition. In the second step, the Si (100) single crystal substrate is heated to change the barrier film formed in the first step into a barrier film crystallized by solid phase epitaxial growth. In the third step, the metal sulfide epitaxial film is epitaxially grown on the barrier film crystallized in the second step by sputtering using a target having the metal sulfide composition.

The temperature of the Si (100) single crystal substrate is preferably suppressed to 90 ° C. or lower in the first step and heated to 500 ° C. or higher and 1000 ° C. or lower in the second step.

Another invention is an apparatus for producing a template substrate in which an epitaxial film of a metal sulfide is laminated on a Si (100) single crystal substrate, and includes a first and a second film formation processing chamber and a transfer chamber. Prepare.

In the first film formation chamber, the metal sulfide barrier film is formed by sputtering on the Si (100) single crystal substrate on the Si (100) single crystal substrate using the metal sulfide as a target. The Si (100) single crystal substrate on which the barrier film is formed in the first film formation chamber is transferred to the second film formation chamber via the transfer chamber. In the second film formation chamber, a target having the same composition as the metal sulfide target is used in a state where the Si (100) single crystal substrate on which the barrier film is formed in the first film formation chamber is heated and held. Then, an epitaxial thin film of the metal sulfide is formed by sputtering.

The temperature of the Si (100) single crystal substrate is preferably suppressed to 90 ° C. or lower in the first film formation chamber and heated to 500 ° C. or higher and 1000 ° C. or lower in the second film formation chamber.

The effects obtained by the present invention will be briefly described as follows.

That is, a template substrate obtained by epitaxially growing a metal sulfide thin film on a Si (100) single crystal substrate can be continuously produced with good reproducibility by a sputtering method.

FIG. 1 is a schematic diagram showing a configuration example of a template substrate according to the present invention. FIG. 2 is a plan view schematically showing a configuration example of a template substrate manufacturing apparatus according to the present invention. FIG. 3 is a schematic explanatory diagram of the first step. FIG. 4 is a schematic explanatory diagram of the second step. FIG. 5 is a schematic explanatory diagram of the third step. FIG. 6 is an explanatory diagram showing the results of an experiment in which the thickness of the MnS layer in the first step was changed. FIG. 7 is an explanatory diagram showing the results of an experiment in which the substrate temperature in the first step was changed. FIG. 8 is an explanatory view showing the results of an experiment in which the substrate temperature in the second to third steps was changed. FIG. 9 is a diagram showing an XRD measurement result (two-dimensional image) using a two-dimensional detector when a good epitaxial film is formed. FIG. 10 is a diagram showing an XRD measurement result (two-dimensional image) using a two-dimensional detector when an epitaxial film having a slightly poor crystallinity is formed. FIG. 11 is a diagram showing an XRD measurement result (two-dimensional image) using a two-dimensional detector when a polycrystalline film is formed.

1. First, an outline of a typical embodiment disclosed in the present application will be described.

As described above, in the epitaxial growth of a metal sulfide thin film on a Si substrate by a sputtering method, the present inventors formed a film when the sputtering film formation on a plurality of Si substrates in the same chamber was sequentially repeated. It has been found that the crystallinity of the metal sulfide thin film gradually deteriorates and it becomes impossible to epitaxially grow. As a result of examining the cause of such a reproducibility problem that makes epitaxial growth impossible, the following conclusions were obtained. That is, when the sputtering film formation is repeated, the metal sulfide film adheres to the inner wall of the chamber, and the inner wall of the chamber is simultaneously heated by the radiation of the substrate heating when the substrate is heated before the film formation. It was inferred that sulfur with a high vapor pressure was released from the steel and that the sulfur damages the surface of the Si substrate being heated.

As a result of further studies by the present inventors, an amorphous metal sulfide thin film formed on a Si single crystal substrate at a low temperature is considered to be a barrier against sulfur that is presumed to damage the surface of the Si substrate during subsequent heating. In addition, it has been found that solid phase epitaxial growth occurs during substrate heating. At this time, it is found that sulfur damage to the surface of the Si substrate appears at a temperature higher than 90 ° C., and the film formation of the amorphous metal sulfide thin film serving as the barrier film must be 90 ° C. or less, It was also found that the amorphous metal sulfide thin film has a film thickness of 10 nm or less that allows solid phase epitaxial growth during subsequent heating. Here, since the metal sulfide thin film functioning as a barrier film is thin, it is not easy to accurately observe the crystallinity, but the substrate temperature when formed is 90 ° C. or less. It is strongly inferred that it is amorphous. However, even if it is not amorphous, even if it is polycrystalline, it does not change that it has a protective function as a barrier film, and as long as solid phase epitaxial growth is performed by subsequent heating, the solution principle of the present invention is Nor does it require any change.

Therefore, typical embodiments of the present invention are as follows. Reference numerals in the drawings referred to in parentheses in the outline description of the representative embodiments merely exemplify what are included in the concept of the components to which the reference numerals are attached.

A typical embodiment of the present invention is a method for manufacturing a template substrate in which a metal sulfide epitaxial film (3, 4) is laminated on a silicon (Si) (100) single crystal substrate (1), A template substrate manufacturing method including the following first to third steps.

The first step forms the metal sulfide barrier film (2) on the Si (100) single crystal substrate (1) by sputtering using a target (6) having a metal sulfide composition. It is a process. The second step is a step of heating the Si (100) single crystal substrate (1) to crystallize the barrier film (2) formed in the first step by solid phase epitaxial growth. The crystallized barrier film is referred to by reference numeral “3”. In the third step, the metal sulfide epitaxial film (3) is formed on the barrier film (3) crystallized in the second step by sputtering using the target (6) having the metal sulfide composition. 4) is a step of epitaxial growth.

Thereby, a template substrate obtained by epitaxially growing a metal sulfide thin film on a Si (100) single crystal substrate can be continuously produced with good reproducibility by a sputtering method.

Here, a more preferred embodiment is as follows.

In the first step, the Si (100) single crystal substrate (1) is held at 90 ° C. or lower. The barrier film (2) formed at this time is amorphous. Here, the lower limit of the substrate temperature is not particularly limited, and is set to room temperature (room temperature), for example, and the upper limit is obtained experimentally.

In the second step, the Si (100) single crystal substrate (1) is heated to 500 ° C. or higher and 1000 ° C. or lower. Here, the lower limit and the upper limit of the substrate temperature are obtained experimentally.

The film thickness of the barrier film (2) formed in the first step is preferably 0.5 nm or more and 10 nm or less. Here, the lower limit of 0.5 nm corresponds to the lattice constant when the metal sulfide is crystallized, and is generally a diatomic layer, and the upper limit is obtained experimentally.

The metal sulfide is preferably manganese sulfide (MnS), magnesium sulfide (MgS), or calcium sulfide (CaS).

By sequentially repeating the sputtering film formation on a plurality of Si substrates in the same chamber, the substrate temperature in the chamber is set to be high when mass-produced and epitaxial growth of the metal sulfide thin film on the Si substrate is continuously performed. It is preferable to hold at a high temperature (preferably 500 ° C. or higher and 1000 ° C. or lower) that enables epitaxial growth. At this time, when the Si (100) single crystal substrate having no barrier layer is introduced into the chamber, the present inventors say that sulfur in the chamber damages the Si (100) single crystal substrate. I realized there was a problem. However, after the substrate temperature in the chamber is lowered to 90 ° C. or lower, the barrier layer is formed by the first step, and the substrate temperature is increased to a high temperature (for example, 500 ° C. or higher and 1000 ° C. or lower), the metal It has been found that when epitaxial growth of a sulfide thin film is performed, the time required for lowering the substrate temperature, the time for increasing the substrate temperature, and the time for stabilizing the substrate are required.

Therefore, another exemplary embodiment of the present invention is a template substrate manufacturing apparatus including first and second film formation processing chambers (12, 13) and a transfer chamber (10). It is configured as follows.

In the first film formation chamber (12), a metal sulfide is used as a target (6) on the Si (100) single crystal substrate (1), and the metal sulfide is applied on the Si (100) single crystal substrate (1). A barrier film (2) of the object is formed by sputtering.

In the second film formation chamber (13), the Si (100) single crystal substrate (1) on which the barrier film (2) was formed in the first film formation chamber was heated to form a film. The barrier film (2) is crystallized by solid phase epitaxial growth, and the Si (100) single crystal substrate (1) is kept heated, and the target (6) having the same composition as the metal sulfide target is used. Then, an epitaxial film (4) of the metal sulfide is formed by sputtering.

In the transfer chamber (10), the Si (100) single crystal substrate (1) on which the barrier film (2) is formed in the first film formation chamber (12) is transferred to the second film formation chamber (10). It is a space for transporting to 13).

Thus, high throughput can be maintained when a template substrate obtained by epitaxially growing a metal sulfide thin film on a Si (100) single crystal substrate is continuously produced with good reproducibility by a sputtering method.

Here, a more preferred embodiment is as follows.

In the first film formation chamber (12), the Si (100) single crystal substrate (1) is held at 90 ° C. or lower until the sputtering film formation is performed. At this time, the barrier film formed in the first film formation chamber is amorphous. The sputtering film formation in the first film formation chamber (12) corresponds to the first step described above. Similarly, the lower limit of the substrate temperature is not particularly limited, and is set to room temperature (room temperature), for example. Required experimentally.

The thickness of the barrier film (2) is preferably 0.5 nm or more and 10 nm or less. The preferred range of the barrier film (2) here is also defined in the same manner as described above.

In the second film formation chamber (13), the Si (100) single crystal substrate (1) is heated and held at 500 ° C. or higher and 1000 ° C. or lower. Here, when the Si (100) single crystal substrate (1) is transferred to the second film formation processing chamber (13) and the substrate temperature is heated, the barrier film corresponds to the second step described above. The step of crystallizing (2) by solid phase epitaxial growth and forming the metal sulfide epitaxial film (4) by subsequent sputtering corresponds to the third step described above. At this time, the lower limit and the upper limit of the substrate temperature are obtained experimentally as described above.

The metal sulfide is preferably MnS, MgS or CaS.

In a more preferred template substrate manufacturing apparatus, the transfer chamber (10) includes a substrate transfer robot (30), and further includes a load lock chamber (11) to support a multi-chamber system.

The effects achieved by the present invention are summarized as follows.

In the present invention, the Si (100) single crystal substrate (1) is held at 90 ° C. or lower, and the metal sulfide target (6) is sputtered to form a metal sulfide to form the Si (100). ) A barrier film (2) is formed on the single crystal substrate (1). At this time, since the Si (100) single crystal substrate (1) is held at a low temperature (for example, 90 ° C. or less), the surface of the Si substrate (1) is damaged by sulfur released from the inner wall of the chamber (9). There is nothing. The barrier film (2) formed in the first step is used when the Si (100) single crystal substrate (1) is heated and held at a high temperature (for example, 500 ° C. or more and 1000 ° C. or less) in the next second step. Furthermore, it functions as a surface protective film against damage to the Si substrate surface due to sulfur released from the inner wall of the chamber. In addition, the amorphous metal sulfide thin film formed in the first step is heated and held at 500 ° C. or higher and 1000 ° C. or lower in the Si (100) single crystal substrate in the second step. Epitaxial growth. In the third step following the second step, the metal sulfide of the first step, which is solid phase epitaxially grown in a state where the Si (100) single crystal substrate is heated and held at a high temperature (for example, 500 ° C. or higher and 1000 ° C. or lower). A metal sulfide thin film (4) is deposited on the thin film (3) by sputtering the metal sulfide target (6) (or the metal sulfide target (6_2) having the same composition as the metal sulfide target (6_1)). Therefore, the metal sulfide thin film (4) in the third step is epitaxially grown.

As described above, in the epitaxial growth of the metal sulfide thin film on the Si substrate by the sputtering method, the problem of reproducibility that cannot be epitaxially grown when the sputtering film formation is continuously repeated can be solved, and on the Si (100) single crystal substrate. In addition, a template substrate on which a metal sulfide thin film is epitaxially grown can be continuously produced with good reproducibility by a sputtering method.

Furthermore, in the present invention, the metal sulfide thin film formed in the first step at the time of heating and holding in the second step can be obtained by setting the thickness of the metal sulfide thin film formed in the first step to 10 nm or less. Solid phase epitaxial growth is possible.

Furthermore, in the present invention, the metal sulfide thin film is any one of MnS (0.5209 nm), MgS (0.5607 nm), and CaS (0.56836 nm) having a lattice constant close to 0.543 nm of Si. Can be epitaxially grown on a Si (100) single crystal substrate, and a template substrate can be produced.

In the present invention, a plurality of independent film forming chambers (12, 13) and a load lock chamber (11) are provided around a transfer chamber (10) provided with a substrate transfer robot (30). A template substrate manufacturing apparatus corresponding to a multi-chamber system, wherein a temperature of the Si (100) single crystal substrate is 90 ° C. or less with a metal sulfide as a target (6_1) on the Si (100) single crystal substrate (1). A first film-forming treatment chamber (12) in which the metal sulfide thin film is formed by sputtering while the metal sulfide thin film is formed in the first film-forming treatment chamber. ) Sputtering of the metal sulfide thin film using the target (6_2) having the same composition as the target of the metal sulfide while the single crystal substrate (1) is heated and held at 500 ° C. or higher and 1000 ° C. or lower. Second deposition process chamber (13) configured to have one by at least one room respectively for. By adopting the structure of the present invention, the first process is performed in the first film forming process chamber, and the second to third processes are performed in the second process chamber. When the first process and the second to third processes are performed in the same film formation chamber, the heating and cooling time of the mechanism for heating and holding the necessary substrate can be saved. 100) A template substrate obtained by epitaxially growing a metal sulfide thin film on a single crystal substrate can be continuously produced with good reproducibility by a sputtering method, and the throughput can be increased and the productivity can be improved.

2. Details of Embodiments Embodiments will be further described in detail.

[Example 1]
FIG. 1 is a schematic diagram showing a configuration example of a template substrate according to the present invention. 1 shows a template substrate obtained by epitaxially growing a MnS thin film made of metal sulfide on a Si (100) single crystal substrate. 1 is a Si (100) single crystal substrate, 3 is a MnS layer formed by the first step and solid phase epitaxially formed in the second step, and 4 is a MnS layer formed by sputtering in the third step. is there.

A method for producing a template substrate in Example 1 will be described in detail.

First, the natural oxide film on the surface of the Si (100) single crystal substrate 1 is removed with hydrofluoric acid (HF (Hydrogen Fluoride) aqueous solution), and sputtering film formation is performed with the surface terminated with hydrogen without being washed with water. It was put in a film forming treatment chamber to be evacuated to 5 × 10 ⁻⁶ Pa. Next, the MnS layer 2 was formed by sputtering on the Si (100) single crystal substrate 1 in the first step by 2 nm. The sputtering film forming conditions in the first step are as follows.

Film formation method: oblique rotation sputtering Sputtering method: RF magnetron sputtering Substrate temperature: 50 ° C. or less (no heating)
Sputtering gas: Argon (Ar)
Sputtering pressure: 2Pa
Target: MnS
Sputtering power: RF150W
Target-to-board distance: 140mm
After forming the MnS layer 2 in the first step, the film formation was temporarily stopped and the substrate temperature was heated to 700 ° C. (second step). In this second step, the MnS layer 2 is considered to be solid phase epitaxially grown. Next, an MnS layer 4 having a thickness of 50 nm was formed in a third step where the sputtering conditions were the same as those in the first step except for the substrate temperature.

FIG. 9 is a diagram showing the X-ray diffraction (XRD) measurement result (two-dimensional image) using the two-dimensional detector of the template substrate of the first embodiment. A bright spot having no bright line in the χ direction of MnS (200) was observed at 2θ = 34.4 °, and the MnS layer 3 and the MnS layer 4 were monocrystal epitaxially grown on the Si (100) single crystal substrate 1. Show.

According to the above-described embodiment, the XRD measurement result shown in FIG. 9 can be obtained even if the sputtering film formation is repeatedly performed, and the template substrate obtained by epitaxially growing the MnS thin film on the Si (100) single crystal substrate is stable with good reproducibility. It was possible to make it.

In Example 1, the sputtering film forming conditions other than the substrate temperature are the same between the first process and the third process, but may be optimized in each process.

[Example 2]
FIG. 2 is a plan view schematically showing a configuration example of a template substrate manufacturing apparatus according to the present invention. The template substrate manufacturing apparatus exemplified in the second embodiment is a multi-chamber system in which a plurality of independent film formation processing chambers and load lock chambers are provided around a transfer chamber provided with a substrate transfer robot. Correspond. In the multi-chamber system, a transfer chamber 10 provided with a substrate transfer robot 30, a load lock chamber 11, a first film formation processing chamber 12, and a second film formation processing chamber 13 around the gate chamber 21 are provided. , 22 and 23. A vacuum pump (not shown) is connected to each of the transfer chamber 10, the load lock chamber 11, the first film forming chamber 12, and the second film forming chamber 13. It is designed to be evacuated.

The processing procedure using the template substrate manufacturing apparatus will be described below. 3, 4 and 5 are schematic explanatory views of the first, second and third steps, respectively. 3, 4, and 5, 6_1 and 6_2 are sputtering targets for the metal sulfide, 7_1 and 7_2 are substrate holders, 8_1 and 8_2 are heaters, and 9_1 and 9_2 are chambers. The heaters 8_1 and 8_2 are not particularly limited. For example, the heaters 8_1 and 8_2 can be heated by, for example, heating wires, and the substrate can be heated via the substrate holders 7_1 and 7_2 by supplying power from the outside. Radio frequency (RF) electrodes are installed in the chambers 9_1 and 9_2, respectively, and a sputtering gas (for example, Ar) is plasma-discharged by RF power supplied from the outside. In addition to an evacuation device comprising a vacuum pump installed inside the chamber 9 or connected to the outside, the RF electrode, sputtering gas introduction pipe and valve, vacuum gauge, substrate thermometer and other sensors are not shown. ing.

First, the natural oxide film on the surface of the Si (100) single crystal substrate 1 is removed with HF, introduced into the load lock chamber 11 with the surface terminated with hydrogen without being washed with water, and the load lock chamber 11 is introduced by a vacuum pump. The inside is evacuated. After the load lock chamber 11 is evacuated to a desired pressure, the Si (100) single crystal substrate 1 is transferred from the load lock chamber 11 to the first film formation chamber by the substrate transfer robot 30 via the

gate valves

21 and 22. 12 to transport.

Next, in the first film formation chamber 12, the Si (100) single crystal substrate 1 is kept at a temperature of 90 ° C. or lower and a metal sulfide (for example, MnS) is used as the target 6_1 for the Si (100). ) A metal sulfide thin film 2 is formed on the single crystal substrate 1 by sputtering, that is, the first step, for example, the first step described in the first embodiment is performed. For example, as shown in FIG. 3, the metal sulfide (for example, MnS) layer 2 is formed by sputtering while the substrate temperature of the Si (100) single crystal substrate 1 is kept low without performing the substrate heating by the heater 8_1. At this time, metal sulfide adheres to the inner wall of the chamber 9_1. When a plurality of Si (100) single crystal substrates 1 are sequentially introduced into the transfer chamber 9_1 and the metal sulfide layer 2 is sputtered and carried out by sputtering, the inner wall of the chamber 9_1 is repeatedly formed. The metal sulfide adhering to the surface increases. However, since the Si (100) single crystal substrate 1 is not heated, the temperature of the inner wall of the chamber 9_1 does not increase. For this reason, the amount of sulfur released from the inner wall and released into the atmosphere is small (almost no), and the substrate temperature is kept low, so that the clean Si surface of the Si (100) single crystal substrate 1 can be obtained. Even if exposed, the reaction with sulfur is suppressed and no damage occurs.

After the completion of the first step in the first film formation chamber 12, the Si (100) single crystal substrate 1 on which the film was formed in the first step is transferred by the substrate transfer robot 30 via the

gate valves

22 and 23. Then, the film is transferred from the first film formation chamber 12 to the second film formation chamber 13. In the second film formation chamber 13, the same composition as that of the metal sulfide target is obtained in a state where the Si (100) single crystal substrate 1 on which the film is formed in the first step is heated to 500 ° C. or higher and 1000 ° C. or lower. The metal sulfide thin film is formed by sputtering using the target 6_2. That is, the second step of heating the Si (100) single crystal substrate 1 to a high temperature, for example, the second step described in Example 1, and the sputtering film formation on the Si (100) single crystal substrate 1 heated and held at a high temperature. For example, the third step described in the first embodiment is performed. For example, as shown in FIG. 4, the Si (100) single crystal substrate 1 on which the film is formed in the first step is heated to 500 ° C. or higher and 1000 ° C. or lower by the heater 8_2. More specifically, by transporting and placing the Si (100) single crystal substrate 1 on which the film formation in the first step has been performed on the holder 7_2 that is heated and held at 500 ° C. or higher and 1000 ° C. or lower. Then, the substrate temperature rises toward the temperature of the holder 7_2, and the metal sulfide thin film 2 formed in the first step in the process changes into the metal sulfide film 3 by solid phase epitaxial growth (second step). ). Thereafter, as shown in FIG. 5, for example, a metal sulfide (eg, MnS) layer 4 is formed by sputtering on the metal sulfide film 3 while keeping the substrate temperature of the Si (100) single crystal substrate 1 at a high temperature ( (3rd process). At this time, metal sulfide adheres to the inner wall of the chamber 9_2. When a plurality of Si (100) single crystal substrates 1 are sequentially transferred and introduced into the chamber 9_2, and the metal sulfide layer 4 is formed by sputtering and carried out, the chamber 9_2 is repeatedly carried out. The metal sulfide adhering to the inner wall increases. Since the temperature of the substrate holder 7_2 is kept high by the heater 8_2, the inner wall of the chamber 9_2 is heated by the radiation, and sulfur having a high vapor pressure is released from the inner wall surface and released into the atmosphere. However, since the metal sulfide layer 2 is formed on the surface of the Si (100) single crystal substrate 1 transported and introduced into the atmosphere, the metal sulfide layer 2 is made up of sulfur in the atmosphere and Si (100 ) Functions as a barrier film that hinders reaction with the Si surface of the single crystal substrate 1.

The Si (100) single crystal substrate 1 formed in the third step in the second film formation chamber 13 is transferred from the second film formation chamber 13 to the load lock chamber via the

gate valves

23 and 21. 11 and after cooling, the load lock chamber 11 is vented and taken out. In the series of processing steps, the

gate valves

21, 22, and 23 are controlled so as not to be simultaneously opened so that the vacuum state of each chamber does not affect each other.

In the second embodiment, the first step, the second step, and the third step are individually performed in the first film formation chamber 12 and the second film formation chamber 13, respectively. The substrate heating mechanism (heater 8_2 shown in FIGS. 3 and 4) of the chamber 13 can be kept heated, and the first step and the second and third steps are performed in the same film formation chamber. In this case, the time required for heating and cooling the substrate heating mechanism can be saved.

As the metal sulfide targets 6_1 and 6_2 attached to the first film formation chamber 12 and the second film formation chamber 13 of the second embodiment, MgS or CaS can be used in addition to MnS.

In the second embodiment, the load lock chamber 11, the first film formation processing chamber 12, and the second film formation processing chamber 13 are each set as one chamber. A plurality can be arranged around the gate valve. For example, two load lock chambers may be used, one dedicated to loading and the other dedicated to unloading, and the time occupied by exhaust and vent in a series of processing times can be shortened. In addition, a plurality of second film formation processing chambers 13 for performing the second and third steps that require a longer processing time than the first step may be arranged, resulting in high throughput and improved productivity. .

In the above embodiment, MnS is shown as the metal sulfide. However, MgS or CaS can also be epitaxially grown on a Si (100) single crystal substrate, and a template substrate can be produced.

Example 3
The film thickness and substrate temperature of the metal sulfide film 2 in the first step and the substrate temperature in the second step will be examined in more detail. FIG. 6, FIG. 7 and FIG. 8 show the results of the experiment in which the thickness of the MnS layer, which is an example of the metal sulfide film 2 in the first step, was changed, and the results of the experiment in which the substrate temperature in the first step was changed. FIG. 6 is an explanatory diagram showing results of experiments in which the substrate temperature in the second to third steps was changed. All are the results of evaluating the crystallinity of the metal sulfide (MnS) film formed by sputtering in the third step. “○” indicates that a good epitaxial film has been formed, “△” indicates that an epitaxial film having slightly poor crystallinity has been formed, and “×” indicates that a polycrystalline film has been formed. It represents what has been done.

The crystallinity of the metal sulfide (MnS) film was evaluated based on the results observed by X-ray diffraction (XRD) using a two-dimensional detector. FIG. 9 is a diagram showing an XRD measurement result (two-dimensional image) using a two-dimensional detector when a good epitaxial film is formed. In addition to the 2θ direction representing the intensity of the diffracted X-ray equal to the incident angle θ of the incident X-ray, the intensity of the two-dimensional diffracted X-ray in the plane perpendicular to the 2θ direction is represented by a two-dimensional image as the χ direction.

FIG. 9 is a diagram showing an XRD measurement result (two-dimensional image) using a two-dimensional detector when a good epitaxial film is formed. A bright spot (spot) having no bright line in the χ direction of MnS (200) is observed at 2θ = 34.4 °, and it can be seen that the axes are aligned in the direction perpendicular to the substrate surface and in the in-plane direction. That is, it shows that the MnS layer is monocrystal epitaxially grown on the Si (100) single crystal substrate 1 (corresponding to the “◯” mark).

FIG. 10 is a diagram showing an XRD measurement result (two-dimensional image) using a two-dimensional detector when an epitaxial film having slightly poor crystallinity is formed. Although (100) is oriented, bright lines extend in the χ direction, indicating that the in-plane orientation is slightly poor. That is, the deposited MnS layer is an epitaxial film having a slightly poor crystallinity (corresponding to the “Δ” mark).

FIG. 11 is a diagram showing an XRD measurement result (two-dimensional image) using a two-dimensional detector when a polycrystalline film is formed. Although (100) is oriented, a ring-like bright line is observed in the χ direction, indicating that there is no orientation in the in-plane direction. That is, the formed MnS layer is a polycrystalline film (corresponding to the “x” mark).

FIG. 6 is an explanatory diagram showing the results of an experiment in which the thickness of the MnS layer in the first step was changed. The thickness of the MnS layer in the first step is changed to 1 nm, 2 nm, 5 nm, 10 nm, 15 nm, and 20 nm, and the crystallinity of the MnS film formed after performing the second to third steps is It summarizes the results of evaluation using XRD using a two-dimensional detector. Conditions other than the film thickness of the MnS layer in the first step are the same as the conditions shown in Example 1 above. When the thickness of the MnS layer is 1 nm, 2 nm, and 5 nm, a good epitaxial film is formed (“◯” mark). It was observed that when the film thickness was 10 nm, it was an epitaxial film with slightly poor crystallinity (“Δ” mark), and at 15 nm and 20 nm, it was a polycrystalline film (“×” mark).

FIG. 7 is an explanatory diagram showing the results of an experiment in which the substrate temperature in the first step was changed. The substrate temperature when the MnS film 2 is formed by sputtering in the first step is changed to 25 ° C., 50 ° C., 70 ° C., 90 ° C., and 110 ° C., and the second to third steps are performed. The results of evaluating the crystallinity of the formed MnS film using XRD using a two-dimensional detector are summarized. Conditions other than the substrate temperature in the first step are the same as the conditions shown in the first embodiment. When the substrate temperature is 25 ° C., 50 ° C., and 70 ° C., a good epitaxial film is formed (“◯” mark). It was observed that the substrate temperature was 90 ° C. and the film was slightly poor in crystallinity (“Δ” mark), and 110 ° C. was a polycrystalline film (“×” mark).

FIG. 8 is an explanatory view showing the results of an experiment in which the substrate temperature in the second to third steps was changed. After performing the first step under the conditions shown in Example 1, the substrate temperatures in the second to third steps are changed to 400 ° C., 500 ° C., 700 ° C., 900 ° C., 1000 ° C., 1100 ° C. This is a summary of the results of evaluating the crystallinity of the MnS film formed after performing the second to third steps using XRD using a two-dimensional detector. Conditions other than the substrate temperature in the first step are the same as the conditions shown in the first embodiment. When the substrate temperature is 700 ° C. and 900 ° C., a good epitaxial film is formed (“◯” mark). It was observed that when the substrate temperature was 500 ° C. or 1000 ° C., it was an epitaxial film with slightly poor crystallinity (“Δ” mark), and at 400 ° C. and 1100 ° C., it was a polycrystalline film (“×” mark). .

From the above experimental results, the sputtering conditions shown in Examples 1 and 2 are not limited to these, and the substrate temperature in the first step is maintained at 90 ° C. or lower, and the MnS layer in the first step. It can be seen that it is preferable to set the film thickness of No. 2 to 10 nm or less and to heat and hold the substrate temperature in the second to third steps at 500 ° C. or more and 1000 ° C. or less. Further, the substrate temperature in the first step is maintained at 70 ° C. or less, the film thickness of the MnS layer 2 in the first step is 5 nm or less, and the substrate temperature in the second to third steps is 700 ° C. or more and 900 ° C. It is more preferable to heat and maintain the following. Here, the lower limit of the substrate temperature in the first step is arbitrary, but it is room temperature or simply the substrate unless there is a special reason such as the need to actively cool the substrate in another step performed in the same chamber. Is not heated (the heater is turned off). In addition, the MnS layer 2 in the first step may function as a barrier film and may be a film thickness that crystallizes depending on the substrate temperature in the second step. It is about 0.5 nm, which is equivalent to a lattice constant (corresponding to a diatomic layer).

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited thereto, and it goes without saying that various modifications can be made without departing from the scope of the invention.

For example, the sputtering method may be changed to another film forming method such as a CVD method. For the epitaxial film formation of the metal sulfide film in the third step, a barrier layer is formed before the substrate is heated to a high temperature, and the barrier layer is crystallized by the substrate heating for the epitaxial film formation. It is because it is good. Therefore, only one of the film formation methods in the first step or the third step may be changed to another film formation method such as a CVD method.

The present invention can be widely applied to a method and an apparatus for manufacturing a template substrate suitable for use in a high-luminance blue light-emitting element, an insulated gate field effect transistor, a high electron mobility transistor, and other electronic devices.

DESCRIPTION OF SYMBOLS 1 Si (100) single crystal substrate 2 MnS layer formed by sputtering at a low substrate temperature 3 MnS layer formed by solid phase epitaxial growth 4 MnS layer formed by sputtering at a high substrate temperature (epitaxial film)
6 Target 7 Base holder 8 Heater 9 Chamber 10 Transfer chamber 11 Load lock chamber 12 First film formation chamber 13 Second

film formation chamber

21, 22, 23 Gate valve 30 Robot for substrate transfer

Claims

A method for producing a template substrate in which an epitaxial film of a metal sulfide is laminated on a silicon (Si) (100) single crystal substrate,
A first step of forming a barrier film of the metal sulfide on the Si (100) single crystal substrate by a sputtering method using a target having the composition of the metal sulfide;
A second step of heating the Si (100) single crystal substrate to crystallize the barrier film formed in the first step by solid phase epitaxial growth;
A third step of epitaxially growing the epitaxial film of the metal sulfide on the barrier film crystallized in the second step by a sputtering method using a target having the composition of the metal sulfide. A method for producing a template substrate.
The method for manufacturing a template substrate according to claim 1, wherein the barrier film formed in the first step is amorphous.
The method for manufacturing a template substrate according to claim 1, wherein in the first step, the Si (100) single crystal substrate is held at 90 ° C or lower.
4. The method for manufacturing a template substrate according to claim 3, wherein, in the second step, the Si (100) single crystal substrate is heated to 500 ° C. or higher and 1000 ° C. or lower.
The method for manufacturing a template substrate according to claim 1, wherein the thickness of the barrier film formed in the first step is not less than 0.5 nm and not more than 10 nm.
The template metal substrate according to any one of claims 1 to 5, wherein the metal sulfide is manganese sulfide (MnS), magnesium sulfide (MgS), or calcium sulfide (CaS). Method.
A first film formation chamber for sputtering a metal sulfide barrier film on the Si (100) single crystal substrate with a metal sulfide as a target on the Si (100) single crystal substrate;
Heating the Si (100) single crystal substrate on which the barrier film is formed in the first film formation chamber, and crystallizing the barrier film formed in the first step by solid phase epitaxial growth; A second film forming process in which the Si (100) single crystal substrate is maintained in a heated state and the metal sulfide epitaxial film is formed by sputtering using a target having the same composition as the metal sulfide target. Room,
And a transfer chamber for transferring the Si (100) single crystal substrate on which the barrier film is formed in the first film formation chamber to the second film formation chamber. Substrate manufacturing device.
8. The template substrate manufacturing apparatus according to claim 7, wherein the barrier film formed in the first film forming chamber is amorphous.
The template substrate manufacturing apparatus according to claim 7, wherein the Si (100) single crystal substrate is held at 90 ° C. or lower until the sputtering film formation is performed in the first film formation chamber.
10. The template substrate manufacturing apparatus according to claim 9, wherein, in the second film formation chamber, the Si (100) single crystal substrate is heated and held at 500 ° C. or higher and 1000 ° C. or lower.
The template substrate manufacturing apparatus according to claim 7, wherein the thickness of the barrier film is 0.5 nm or more and 10 nm or less.
12. The template substrate manufacturing apparatus according to claim 7, wherein the metal sulfide is MnS, MgS, or CaS.
The template substrate manufacturing apparatus according to any one of claims 7 to 12, wherein the transfer chamber includes a substrate transfer robot, and further includes a load lock chamber and corresponds to a multi-chamber system.