Hexagonal boron nitride, method for producing the same, and electrical and semiconductor devices

Abstract

The present disclosure relates to hexagonal boron nitride, a method for manufacturing the same, and electronic and semiconductor devices. A method for manufacturing hexagonal boron nitride is disclosed herein, wherein the hexagonal boron nitride is epitaxially grown. A method for manufacturing hexagonal boron nitride includes placing a catalytic metal in a chamber, the catalytic metal having a hexagonal crystal structure and having a lattice mismatch of 15% or less with hexagonal boron nitride (h-BN) in the chamber; and growing the hexagonal boron nitride on the catalytic metal at a temperature of 800°C or less while supplying a nitrogen source and a boron source into the chamber.

Description

Technical Field

[0001] The present disclosure relates to a method of manufacturing hexagonal boron nitride (h-BN), and more particularly, to a method of manufacturing h-BN in which h-BN is epitaxially grown at a relatively low temperature. Background Art

[0002] Hexagonal boron nitride, a material having a two-dimensional structure, has a hexagonal arrangement of boron atoms and nitrogen atoms, has electrical insulating properties due to a high band gap energy of about 5.9 eV, and is chemically and physically stable.

[0003] Hexagonal boron nitride crystals have very strong covalent bonds and have lubricity. In addition, because hexagonal boron nitride has high thermal conductivity, may not have a melting point and sublimates at about 3,000°C, it has high stability at high temperatures and has a very high resistance of 105Ω in a high temperature range of 1000°C or higher. Such hexagonal boron nitride can be mainly used for applications such as insulating films, anti-diffusion films or surface antioxidant films in electrical or electronic devices. In addition, hexagonal boron nitride can be used to make substrates for growing other two-dimensional materials. In addition, because hexagonal boron nitride has a low specific gravity of 2.26, it can be used to reduce the weight of components.

[0004] Such hexagonal boron nitride is generally grown using thermal chemical vapor deposition (T-CVD) at a high temperature of about 1,000° C. to about 1,500° C. Summary of the invention

[0005] According to one aspect, a method for manufacturing hexagonal boron nitride is provided, the method comprising: placing a catalytic metal in a chamber, the catalytic metal having a hexagonal crystal structure and having a lattice mismatch greater than or equal to 0% and less than or equal to 15% with hexagonal boron nitride (h-BN) in the chamber; and growing hexagonal boron nitride on the catalytic metal at a temperature of 800°C or less while supplying a nitrogen source and a boron source into the chamber.

[0006] In some embodiments, the catalytic metal may include crystals of at least one of cobalt (Co), Co-Cr alloy, Co-N alloy, Co-Ir alloy, zinc (Zn), ruthenium (Ru), technetium (Tc), osmium (Os), and rhenium (Re).

[0007] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0008] In some embodiments, the nitrogen source and the boron source may include at least one of borazine, 1,3,5-trimethylborazine, 2,4,6-trimethylborazine, aminoborane, 2,4,6-trichloroborazine, B-tris(methylamino)borazine, and ammonia borane as compounds of boron and nitrogen.

[0009] In some embodiments, the nitrogen source may include ammonia (NH 3 ) gas and nitrogen (N 2 ) at least one of the gases.

[0010] In addition, in some embodiments, the boron source may include a BH 3 , BF 3 , BCl 3 , B 2 H 6 , (CH 3 CH 2 ) 3 B and (CH 3 ) 3 At least one material in B.

[0011] In some embodiments, the nitrogen source and the boron source may be provided by evaporating solid boron nitride powder.

[0012] In some embodiments, the method may further include removing contaminants from a surface of the catalytic metal prior to growing the hexagonal boron nitride.

[0013] In some embodiments, removing contaminants from the surface of the catalytic metal may include: 2 ) gas is supplied into the chamber and the temperature in the chamber is increased to 1,000°C.

[0014] In some embodiments, removing the contaminants may be performed for 20 minutes while supplying hydrogen gas at a flow rate of 100 sccm.

[0015] In some embodiments, growing hexagonal boron nitride can be performed by inductively coupled plasma chemical vapor deposition.

[0016] In some embodiments, growing hexagonal boron nitride may be performed at a temperature ranging from about 350°C to about 800°C.

[0017] In some embodiments, growing hexagonal boron nitride may include: introducing hydrogen (H) at a flow rate of 0 sccm to 100 sccm. 2) gas into the chamber; supplying argon (Ar) gas into the chamber at a flow rate of 0 sccm to 100 sccm; supplying borazine gas into the chamber at a flow rate of 0.01 sccm to 1 sccm; and maintaining the pressure in the chamber at about 0.01 Torr to about 1 Torr.

[0018] In some embodiments, the lattice mismatch between the catalytic metal and the hexagonal boron nitride may be greater than 0% and less than or equal to 10.4%.

[0019] In some embodiments, growing hexagonal boron nitride may provide grown hexagonal boron nitride that may have a single crystal structure.

[0020] In some embodiments, the root mean square surface roughness of the grown hexagonal boron nitride may be greater than or equal to 0 nm and less than or equal to 2 nm.

[0021] Furthermore, the root mean square surface roughness of the grown hexagonal boron nitride may be greater than or equal to 0 nm and less than or equal to 1.7 nm.

[0022] According to another aspect, there is provided hexagonal boron nitride manufactured by one of the above methods. The hexagonal boron nitride may have a single crystal structure and have a root mean square surface roughness greater than or equal to 0 nm and less than or equal to 2 nm.

[0023] According to another aspect, an electric device is provided, comprising: hexagonal boron nitride manufactured by one of the above methods; and a two-dimensional material on the hexagonal boron nitride.

[0024] In some embodiments, the two-dimensional material may include graphene, transition metal dichalcogenides, black phosphorus, or phosphorene.

[0025] According to another aspect, a semiconductor device includes: a substrate including a source region and a drain region, the source region and the drain region each comprising a doped semiconductor; a first hexagonal boron nitride and a second hexagonal boron nitride, manufactured by one of the above methods and on the substrate, the first hexagonal boron nitride on the source region and the second hexagonal boron nitride on the drain region; a source electrode on the first hexagonal boron nitride; and a drain electrode on the second hexagonal boron nitride.

[0026] According to one aspect, a method for manufacturing hexagonal boron nitride is provided. The method includes: placing a catalytic metal in a chamber, the catalytic metal having a hexagonal crystal structure and including a crystal of at least one of cobalt (Co), Co-Cr alloy, Co-N alloy, Co-Ir alloy, zinc (Zn), ruthenium (Ru), technetium (Tc), osmium (Os) and rhenium (Re); and growing hexagonal boron nitride on the catalytic metal at a temperature in a range of about 350° C. to about 800° C. while supplying a nitrogen source and a boron source into the chamber.

[0027] In some embodiments, growing hexagonal boron nitride may include: introducing hydrogen (H) at a flow rate of 0 sccm to 100 sccm. 2 ) gas is supplied into the chamber; argon (Ar) gas is supplied into the chamber at a flow rate of 0 sccm to 100 sccm; borazine gas is supplied into the chamber at a flow rate of 0.01 sccm to 1 sccm; and the pressure in the chamber is maintained at 0.01 Torr to 1 Torr.

[0028] In some embodiments, growing hexagonal boron nitride is performed by inductively coupled plasma chemical vapor deposition.

[0029] In some embodiments, the method may further include removing contaminants from a surface of the catalytic metal prior to growing the hexagonal boron nitride.

[0030] In some embodiments, the nitrogen source and the boron source may include at least one of borazine, 1,3,5-trimethylborazine, 2,4,6-trimethylborazine, aminoborane, 2,4,6-trichloroborazine, B-tris(methylamino)borazine, and ammonia borane. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above / other aspects, features and advantages of certain embodiments of the present disclosure will be more apparent from the following description in conjunction with the accompanying drawings, in which:

[0032] Figure 1 is a schematic diagram of a system for manufacturing hexagonal boron nitride according to one embodiment;

[0033] Figure 2 is through Figure 1 Atomic force microscope image of the surface of hexagonal boron nitride manufactured by the system;

[0034] Figure 3 Shown by Figure 1 Low-energy electron diffraction measurement results of hexagonal boron nitride manufactured by the system;

[0035] Figure 4 is a graph showing the results of Raman spectroscopy measurement of hexagonal boron nitride grown at a temperature of 400° C.;

[0036] Figure 5 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown at a temperature of 500° C.;

[0037] Figure 6 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown at a temperature of 600° C.;

[0038] Figure 7is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown at a temperature of 800° C.;

[0039] Figure 8 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown by the method according to Comparative Example 1;

[0040] Fig. 9 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown by the method according to Comparative Example 2;

[0041] FIG. 10A to FIG. 10E is a schematic perspective view showing a process of manufacturing a field effect transistor using hexagonal boron nitride; and

[0042] Fig.11 is a cross-sectional view showing a schematic structure of a semiconductor device including hexagonal boron nitride. DETAILED DESCRIPTION

[0043] Reference will now be made in detail to the embodiments illustrated in the accompanying drawings, examples of which are shown in the drawings, wherein like reference numerals refer to like elements throughout. In this regard, the embodiments of the inventive concept may have different forms and should not be construed as being limited to the descriptions set forth herein. Therefore, the embodiments are described below with reference to the accompanying drawings only to explain various aspects. When used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0044] Expressions such as “at least one of,” when following a list of elements, modify the entire list of elements without modifying the individual elements in the list. Expressions such as “at least one of,” when following a list of elements (e.g., A, B, and C), modify the entire list of elements without modifying the individual elements in the list. For example, “at least one of A, B, and C,” “at least one of A, B, or C,” “one of A, B, C, or a combination thereof,” and “one of A, B, C, and a combination thereof” may be interpreted to cover any of the following combinations: A; B; A and B; A and C; B and C; and A, B, and C, respectively.

[0045] Hereinafter, the method for manufacturing hexagonal boron nitride will be described in detail with reference to the accompanying drawings. In the following figures, the same reference numerals refer to the same elements, and the size of each element may be exaggerated for clarity and ease of description. In addition, the following embodiments are merely illustrative and may be modified in various ways. In addition, in the following layer structure, the expression "above" or "on" may include not only directly contacting on / below / left / right of..., but also non-contacting on / below / left / right of...

[0046] Hexagonal boron nitride (h-BN) comprises boron atoms and nitrogen atoms arranged alternately in a planar hexagonal crystal structure. Hexagonal boron nitride has an interlayer structure in which adjacent boron atoms and nitrogen atoms overlap each other due to the polarity of the two atoms. Hexagonal boron nitride can be used in various applications because it is very inactive in an oxidizing atmosphere, has high thermal conductivity and high electrical insulation properties, and has stable chemical properties. The present disclosure provides a method for epitaxially growing hexagonal boron nitride at relatively low temperatures.

[0047] For example, Figure 1 is a schematic diagram of a system for manufacturing hexagonal boron nitride according to one embodiment. Figure 1 , hexagonal boron nitride can be grown using an inductively coupled plasma chemical vapor deposition (ICP-CVD) system 10. The inductively coupled plasma chemical vapor deposition system 10 may include a chamber 11 in which a reaction occurs, source inlets 12 and 13 for providing a source gas 15 into the chamber 11, and a coil 14 for ionizing the source gas 15 introduced into the chamber 11 and generating a plasma 17. The coil 14 may be located in the chamber 11 or may be located outside the chamber 11. The inductively coupled plasma chemical vapor deposition system 10 may have other various structures. However, the detailed structure of the inductively coupled plasma chemical vapor deposition system 10 is beyond the scope of the present embodiment, and thus its detailed description will be omitted.

[0048] First, according to one embodiment, the catalytic metal 16 is placed in the chamber 11. The catalytic metal 16 may have a flat thin film form. The catalytic metal 16 may include a metal material having a hexagonal crystal structure identical to that of hexagonal boron nitride. Specifically, the catalytic metal 16 may include a metal material having a lattice mismatch of 15% or less (e.g., greater than or equal to 0% and less than or equal to 15%) with hexagonal boron nitride. For example, the catalytic metal 16 may include a crystal of at least one material selected from cobalt (Co), Co-Cr alloy, Co-N alloy, Co-Ir alloy, zinc (Zn), ruthenium (Ru), technetium (Tc), osmium (Os) and rhenium (Re). For example, the lattice constant of hexagonal boron nitride is about 250 pm (picometer), and the lattice constant of rhenium (Re) is about 276.1 pm, so that the lattice mismatch between rhenium (Re) and hexagonal boron nitride is about 10.4%. In addition, the lattice constant of cobalt (Co), which has the lowest lattice mismatch of about 0.3% with hexagonal boron nitride, is about 250.71 pm. Therefore, the range of metal materials can be further limited, so that metal materials having a lattice mismatch of 10.4% or less with hexagonal boron nitride can be used as the catalytic metal 16.

[0049] In order to make the catalytic metal 16 have a hexagonal crystal structure, the catalytic metal 16 pre-grown on a growth substrate (not shown) having a hexagonal crystal structure may be used. For example, the catalytic metal 16 is grown on an aluminum oxide (Al2O3) substrate at a suitable temperature. 2 O 3 ) substrate. The growth temperature conditions that allow the catalytic metal 16 to have a hexagonal crystal structure may vary depending on the metal material. Although the catalytic metal 16 is separated from the growth substrate and only the catalytic metal 16 is placed in the chamber 11, both the growth substrate and the catalytic metal 16 may be placed in the chamber 11.

[0050] In addition, the surface of the catalytic metal 16 may be selectively processed to improve smoothness before the catalytic metal 16 is placed in the chamber 11. For example, at least one of chemical polishing, physical polishing, chemical mechanical polishing, and electropolishing may be used as a polishing process.

[0051] After the catalytic metal 16 is placed in the chamber 11, contaminants such as carbon may be selectively removed from the surface of the catalytic metal 16. For example, in a hydrogen atmosphere, contaminants such as carbon present on the surface of the catalytic metal 16 may be removed by combining with hydrogen. For example, when hydrogen (H2) is introduced at a flow rate of about 100 sccm, 2 ) is supplied into the chamber 11, the temperature in the chamber 11 may be raised to 1000° C. The process of removing the pollutants may be performed for about 20 minutes. While removing the pollutants, no current is applied to the coil 14. If there are almost no pollutants on the surface of the catalytic metal 16, the process of removing these pollutants may be omitted.

[0052] After removing contaminants from the surface of the catalytic metal 16, hexagonal boron nitride may be grown on the catalytic metal 16 by inductively coupled plasma chemical vapor deposition. According to the present embodiment, hexagonal boron nitride may be grown on the catalytic metal 16 at a temperature of 800° C. or less while a nitrogen source and a boron source are supplied into the chamber 11. To this end, the nitrogen source and the boron source are mixed with hydrogen (H2) while the temperature in the chamber 11 is maintained at 800° C. or less. 2 ) or a mixture of argon and hydrogen (Ar / H 2 ) are provided into the chamber 11. At the same time, current is applied to the coil 14.

[0053] Nitrogen and boron compounds can be used as nitrogen and boron sources. For example, the nitrogen and boron compounds can include a borazine (BH) 3 (NH) 3 ), aminoborane (NH 2 BH 2 ), ammonia borane (H 3 NBH 3)、1,3,5-trimethylborazine (C 3 H 12 B 3 N 3 )、2,4,6-trimethyl borazine、2,4,6-trichloro borazine (B 3 Cl 3 H 3 N 3 ) and B-tri(methylamino)borazine (B 3.0 N 4.4±0.1 C 2.0±0.1 H 9.3±0.2 Alternatively, the compound of nitrogen and boron may be provided into the chamber 11 by evaporating solid boron nitride powder.

[0054] In addition, a nitrogen precursor as a nitrogen source may be provided into the chamber 11, and a boron precursor as a boron source may be provided into the chamber 11. The nitrogen precursor may include, for example, a gas selected from ammonia (NH 3 ) gas and nitrogen (N 2 ) gas. In addition, the boron precursor includes a material selected from borane (BH 3 ), Boron trifluoride (BF 3 ), boron trichloride (BCl 3 ), B 2 H 6 , (CH 3 CH 2 ) 3 B and (CH 3 ) 3 At least one material of B.

[0055] The nitrogen source and the boron source are ionized by the electric field inside the coil 14 while passing through the inside of the chamber 11. As a result, the nitrogen source and the boron source exist in the chamber 11 in the state of plasma 17. Thereafter, the nitrogen atoms and the boron atoms in the state of plasma 17 couple to each other to grow hexagonal boron nitride crystals.

[0056] For example, when hexagonal boron nitride is manufactured using borazine, the temperature in the chamber 11 may be maintained at about 800° C. or less. In addition, borazine may be supplied to the chamber 11 at a flow rate of about 0.01 sccm to about 1 sccm while applying a power of about 500 W or less to the coil 14. At the same time, hydrogen (H2) may be supplied to the chamber 11 at a flow rate of about 0 sccm to about 100 sccm. 2 ) gas is supplied into the chamber 11, and argon (Ar) gas may be supplied into the chamber 11 at a flow rate of about 0 sccm to about 100 sccm. In this case, the pressure in the chamber 11 may be maintained at about 0.01 Torr to about 1 Torr.

[0057] Figure 2 is through Figure 1 Atomic force microscopy images of the surface of hexagonal boron nitride fabricated by the system. For example, Figure 2 Hexagonal boron nitride can be produced using cobalt as the catalytic metal 16 grown to a thickness of 500 nm on an aluminum oxide substrate at a temperature of about 390°C. Figure 2 It can be found that hexagonal boron nitride having a relatively smooth and uniform surface is formed. The hexagonal boron nitride manufactured in this manner is measured to have a root mean square (RMS) surface roughness of about 2 nm or less, and more precisely, a root mean square (RMS) surface roughness of about 1.7 nm or less.

[0058] Figure 3 The measurement results of hexagonal boron nitride produced by the above method using low energy electron diffraction (LEED) are shown. Figure 3 As a result of LEED measurement, six diffraction points arranged in a hexagonal pattern were found. This means that the hexagonal boron nitride formed by the aforementioned method has a single crystal structure. Therefore, the hexagonal boron nitride formed by the aforementioned method can have high quality.

[0059] Figures 4 to 7 is a graph showing the results of Raman spectroscopy measurements of hexagonal boron nitride grown at different temperatures. Figure 4 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown at a temperature of 400° C., Figure 5 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown at a temperature of 500° C., Figure 6 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown at a temperature of 600° C., Figure 7 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown at a temperature of 800°C.

[0060] Reference Figure 4 It can be found that the peak of the Raman spectrum appears at about 1370 cm -1 The Raman spectrum has different peaks depending on the type of material. Because hexagonal boron nitride has a peak at 1370 cm -1 It has a unique peak at , so it can be confirmed that hexagonal boron nitride can be produced even at a temperature of about 400 ° C. Figure 4 In the curve diagram, at 1370cm -1 Peaks were also observed at positions other than . This means that in addition to the heterogeneous components of hexagonal boron nitride, cubic boron nitride (c-BN), amorphous boron nitride (a-BN), and carbon boron nitride (B x C y N z) or BN soot. Figures 5 to 7 As the growth temperature of hexagonal boron nitride increases, a peak appears at 1370 cm -1 In particular, in the case of hBN grown at 600°C and 800°C, 1370 cm -1 The intensity of the peak at is much stronger than that of other peaks.

[0061] from Figures 2 to 7 It can be found from the measurement results that, according to the present embodiment, when a catalytic metal having a lattice mismatch of about 15% or less with hexagonal boron nitride is used, hexagonal boron nitride can be grown even at a low temperature of about 800°C or less. For example, hexagonal boron nitride can be grown in a temperature range of about 350°C to about 800°C. Therefore, since the growth temperature of hexagonal boron nitride is low, the process cost for manufacturing hexagonal boron nitride can be reduced, and the production cost of hexagonal boron nitride can be reduced.

[0062] In addition, because the hexagonal boron nitride manufactured by the method of the present embodiment can have a single crystal structure, the quality of the hexagonal boron nitride can be improved. For example, when the hexagonal boron nitride having a polycrystalline structure is used as an anti-diffusion film or a surface antioxidant film of an electrical device or an electronic device, a dopant or hydrogen may penetrate into the crystal defects of the hexagonal boron nitride. In this case, the performance of the anti-diffusion film or the surface antioxidant film may deteriorate. The hexagonal boron nitride having a single crystal structure can improve the performance of the anti-diffusion film or the surface antioxidant film.

[0063] at the same time, Figure 8 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown by the method according to Comparative Example 1. The hexagonal boron nitride according to Comparative Example 1 was manufactured by ICP-CVD at 700° C., 800° C., and 900° C. using platinum (Pt) crystals having a face-centered cubic structure as a catalytic metal. In addition, in Comparative Example 1, contaminants were not removed from the surface of the platinum catalytic metal. Figure 8 The curve of hexagonal boron nitride produced at 700℃ is shown in Figure 1. -1 There is no peak at about 1365 cm-1 in the hexagonal boron nitride produced at 800℃ and 900℃. -1 A weak peak appears.

[0064] also, Fig. 9 is a graph showing the results of Raman spectrum measurement of hexagonal boron nitride grown by the method according to Comparative Example 2. In Comparative Example 2, contaminants were removed from the surface of the catalytic metal at a temperature of 1000° C. in a hydrogen atmosphere. In addition, hexagonal boron nitride was manufactured under the same conditions as those in Comparative Example 1. Fig. 9The curve of hexagonal boron nitride produced at 700℃ is shown in Figure 1. -1 There is no peak at about 1370 cm-1 in hexagonal boron nitride produced at 800 °C. -1 A weak peak appears at about 1370 cm-1 in hexagonal boron nitride produced at 900 °C. -1 Therefore, it can be found that platinum (Pt), which is mainly used as a catalytic metal when hexagonal boron nitride is manufactured by conventional thermal chemical vapor deposition (T-CVD), is not suitable for growing hexagonal boron nitride at 800°C or lower by the method according to the present embodiment.

[0065] The hexagonal boron nitride manufactured by the aforementioned method according to the present embodiment can be usefully used as a passivation film, such as an anti-diffusion film or a surface antioxidant film. In this case, because the hexagonal boron nitride has a single crystal structure, the performance of the passivation film can be improved. In addition, the hexagonal boron nitride can be used as a substrate for growing other two-dimensional materials such as graphene.

[0066] For example, when hexagonal boron nitride can be used as a substrate for growing other two-dimensional materials, the catalytic metal 16 under the hexagonal boron nitride can be removed. For example, the catalytic metal 16 can be removed by an acidic solution. When the hexagonal boron nitride thin film is coated with a support member such as polymethyl methacrylate (PMMA) before acid treatment and then the catalytic metal 16 is removed, the subsequent transfer process of the hexagonal boron nitride can be facilitated.

[0067] Hexagonal boron nitride has a small lattice mismatch with graphene. Therefore, when a hexagonal boron nitride film is transferred to a catalytic metal for graphene and then graphene is formed by CVD, high-quality graphene can be obtained. In addition to graphene, other two-dimensional materials such as black phosphorus (BP), phosphorene (which is a two-dimensional allotrope), and transition metal dichalcogenides (TMDCs) (which are compounds of transition metals and chalcogen elements) can also be grown on hexagonal boron nitride. For example, transition metal dichalcogenides (such as MoS 2 , WS 2 、TaS 2 , HfS 2 、ReS 2 、TiS 2 , NbS 2 、SnS 2 、MoSe 2 ,WSe 2 、TaSe 2 , HfSe 2 、ReSe 2 、TiSe 2 、NbSe 2 SnSe 2 、MoTe2 、WTe 2 、TaTe 2 、HfTe 2 、ReTe 2 、TiTe 2 、NbTe 2 SnTe 2 ), black phosphorus or phosphorene can be grown on hexagonal boron nitride. In addition, materials such as TiOx, NbOx, MnOx, VaOx, MnO 3 、TaO 3 , WO 3 、MoCl 2 CrCl 3 、RuCl 3 ,BiI 3 、PbCl 4 , GeS, GaS, GeSe, GaSe, PtSe 2 、In 2 Se 3 Various other two-dimensional materials such as GaTe, InS, InSe, and InTe can be grown on hBN.

[0068] In addition, two-dimensional materials grown on hexagonal boron nitride can be used to fabricate electrical or electronic devices such as field effect transistors (FETs). FIG. 10A to FIG. 10E is a schematic perspective view showing a process of manufacturing a field effect transistor using hexagonal boron nitride.

[0069] First, refer to Fig. 10A , the hexagonal boron nitride 22 and the graphene 21 can be placed on a substrate including silicon 23 and a substrate including SiO 2 An insulating film 24 of an insulating material of a silicon-on-insulator (SOI) substrate is formed on the surface of the insulating film 24. For example, the hexagonal boron nitride 22 coated with PMMA is transferred to the SOI substrate, and the PMMA is removed by acetone. Thereafter, the graphene 21 is transferred to the hexagonal boron nitride 22. Alternatively, the hexagonal boron nitride 22 may be transferred to a catalytic metal for growing graphene, the PMMA may be removed, and then the graphene 21 may be grown on the hexagonal boron nitride 22. Thereafter, the catalytic metal for growing graphene is removed, and the hexagonal boron nitride 22 and the graphene 21 thereon are transferred to the SOI substrate.

[0070] Next, refer to Fig. 10B and Fig. 10C , the first electrode 26 and the second electrode 27 are deposited on the graphene 21 by sputtering or the like with the aid of the mask 25. Next, referring to Fig. 10D and Fig.10E, except for the portion covered by the mask 28 between the first electrode 26 and the second electrode 27, the rest of the hexagonal boron nitride 22 and the graphene 21 are removed. For example, the hexagonal boron nitride 22 and the graphene 21 on the SOI substrate can be removed using an O 2 The plasma is removed. In this way, the field effect transistor 20 including the channel made of the graphene 21 can be manufactured. Here, the graphene 21 remaining between the first electrode 26 and the second electrode 27 can function as a channel.

[0071] Although the above reference FIG. 10A to FIG. 10E In the description of FIG. 2 , it is explained that graphene 21 is grown on or transferred to hexagonal boron nitride 22, but this is only an example. In addition to graphene 21, various other two-dimensional materials can be grown on or transferred to hexagonal boron nitride 22 to manufacture electrical devices such as transistors. For example, transition metal dichalcogenides, black phosphorus, phosphorene, TiOx, NbOx, MnOx, VaOx, MnO 3 、TaO 3 , WO 3 、MoCl 2 CrCl 3 、RuCl 3 ,BiI 3 、PbCl 4 , GeS, GaS, GeSe, GaSe, PtSe 2 、In 2 Se 3 Two-dimensional materials of GaTe, InS, InSe and InTe can be grown on or transferred to hexagonal boron nitride 22 instead of graphene 21 to manufacture electronic devices such as field effect transistors.

[0072] At the same time, hexagonal boron nitride can be inserted at the interface between metal and semiconductor to reduce the Schottky barrier occurring at the interface between metal and semiconductor. For example, Fig.11 is a cross-sectional view of a schematic structure of a semiconductor device including hexagonal boron nitride. Fig.11 The semiconductor device 100 may include a semiconductor layer (including a well region 101, a source region 102, and a drain region 103), a metal layer electrically contacting the semiconductor layer (including a source electrode 106 and a drain electrode 107), and hexagonal boron nitride 104 and 105 disposed between the semiconductor layer and the metal layer.

[0073] Here, the semiconductor layer may include a well region 101 formed of a semiconductor doped with a first type dopant, and a source region 102 and a drain region 103 formed of a semiconductor doped with a second type dopant electrically opposite to the first type dopant. Fig.11, the well region 101 is doped with a p-type dopant and the source region 102 and the drain region 103 are doped with an n-type dopant, but this is only an example. The well region 101 may be doped with an n-type dopant, and the source region 102 and the drain region 103 may be doped with a p-type dopant.

[0074] The hexagonal boron nitrides 104 and 105 may include a first hexagonal boron nitride 104 disposed on the source region 102 and a second hexagonal boron nitride 105 disposed on the drain region 103. Fig.11 As shown in FIG. 10A to FIG. 10E As shown, two-dimensional materials such as graphene, transition metal dichalcogenides, black phosphorus, and phosphorene may be additionally grown on or transferred to the hexagonal boron nitride 104 and 105 .

[0075] The metal layer may include a source electrode 106 disposed on the first hexagonal boron nitride 104 and a drain electrode 107 disposed on the second hexagonal boron nitride 105. The metal layer including the source electrode 106 and the drain electrode 107 may include a metal such as magnesium (Mg), aluminum (Al), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), zirconium (Zr), niobium (Nb), molybdenum (Mo), lead (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), lanthanum (La), hafnium (Hf), tantalum (Ta), tungsten (W), iridium (Ir), platinum (Pt), gold (Au), bismuth (Bi) or an alloy thereof.

[0076] The semiconductor device 100 may further include: a gate insulating film 108 disposed on the well region 101 between the source region 102 and the drain region 103; a gate electrode 109 disposed on the gate insulating film 108; and a spacer 110 surrounding the sidewalls of the gate insulating film 108 and the sidewalls of the gate electrode 109. The well region 101, the source region 102, and the drain region 103 may be formed in a semiconductor substrate. The spacer 110 may limit and / or prevent the gate insulating film 108 and the gate electrode 109 from directly contacting the source electrode 106 and the drain electrode 107. The gate insulating film 108 may be made of SiO 2 、SiNx、HfO 2 、Al 2 O 3 The gate electrode 109 may be made of polysilicon or the same metal material as the metal layer. The spacer 110 may be made of SiO 2 Or SiNx insulating material.

[0077] In such a structure, the first hexagonal boron nitride 104 can reduce the Schottky barrier between the source region 102 and the source electrode 106, and the second hexagonal boron nitride 105 can reduce the Schottky barrier between the drain region 103 and the drain electrode 107. Therefore, the contact resistance between the source region 102 and the source electrode 106 and the contact resistance between the drain region 103 and the drain electrode 107 can be reduced.

[0078] It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. The description of features or aspects within each embodiment should generally be considered applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope as defined by the appended claims.

[0079] This application claims the benefit of Korean Patent Application No. 10-2019-0108930 filed on September 3, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A method for producing hexagonal boron nitride, the method comprising: growing a catalytic metal on a growth substrate having a hexagonal crystal structure; placing the catalytic metal in a chamber, the catalytic metal having a hexagonal crystal structure and having a lattice mismatch with hexagonal boron nitride (h-BN) of greater than or equal to 0% and less than or equal to 15%; as well as While a nitrogen source and a boron source are supplied into the chamber, hexagonal boron nitride is grown on the catalytic metal at a temperature ranging from 600° C. to 800° C., the hexagonal boron nitride grown on the catalytic metal having a single crystal structure.

2. The method of claim 1, wherein the catalytic metal comprises crystals of at least one of cobalt (Co), Co-Cr alloy, Co-N alloy, Co-Ir alloy, zinc (Zn), ruthenium (Ru), technetium (Tc), osmium (Os) and rhenium (Re).

3. The method according to claim 1, wherein The nitrogen source and the boron source include at least one of borazine, 1,3,5-trimethylborazine, 2,4,6-trimethylborazine, aminoborane, 2,4,6-trichloroborazine, B-tris(methylamino)borazine and ammonia borane.

4. The method according to claim 1, wherein the nitrogen source comprises at least one of ammonia (NH3) gas and nitrogen (N2) gas.

5. The method of claim 1, wherein the boron source comprises at least one of BH3, BF3, BCl3, B2H6, (CH3CH2)3B, and (CH3)3B.

6. The method of claim 1, wherein the nitrogen source and the boron source are provided by evaporating solid boron nitride powder.

7. The method according to claim 1, further comprising: Prior to growing the hexagonal boron nitride, contaminants are removed from the surface of the catalytic metal.

8. The method of claim 7, wherein removing the contaminants from the surface of the catalytic metal comprises supplying hydrogen (H2) gas into the chamber and increasing the temperature in the chamber to 1,000°C. 9 . The method of claim 8 , wherein removing the contaminants from the surface of the catalytic metal is performed for 20 minutes while supplying the hydrogen gas at a flow rate of 100 sccm.

10. The method of claim 1, wherein growing the hexagonal boron nitride is performed by inductively coupled plasma chemical vapor deposition.

11. The method of claim 1 , wherein growing the hexagonal boron nitride comprises: supplying hydrogen (H2) gas into the chamber at a flow rate of 0 sccm to 100 sccm; supplying argon (Ar) gas into the chamber at a flow rate of 0 sccm to 100 sccm; supplying borazine gas into the chamber at a flow rate of 0.01 sccm to 1 sccm; and The pressure in the chamber was maintained at 0.01 Torr to 1 Torr. 12 . The method of claim 1 , wherein a lattice mismatch between the catalytic metal and the hexagonal boron nitride is greater than or equal to 0% and less than or equal to 10.4%.

13. The method of claim 1, wherein growing the hexagonal boron nitride provides grown hexagonal boron nitride, and the grown hexagonal boron nitride has a root mean square surface roughness of 2 nm or less and greater than or equal to 0 nm. 14 . The method according to claim 13 , wherein the root mean square surface roughness of the grown hexagonal boron nitride is 1.7 nm or less and greater than or equal to 0 nm.

15. A method for producing hexagonal boron nitride, the method comprising: growing a catalytic metal on a growth substrate having a hexagonal crystal structure; placing the catalytic metal in the chamber, the catalytic metal having a hexagonal crystal structure and comprising crystals of at least one of cobalt (Co), Co-Cr alloy, Co-N alloy, Co-Ir alloy, zinc (Zn), ruthenium (Ru), technetium (Tc), osmium (Os), and rhenium (Re); as well as While a nitrogen source and a boron source are supplied into the chamber, hexagonal boron nitride is grown on the catalytic metal at a temperature ranging from 600° C. to 800° C., the hexagonal boron nitride grown on the catalytic metal having a single crystal structure.

16. The method of claim 15, wherein growing the hexagonal boron nitride comprises: supplying hydrogen (H2) gas into the chamber at a flow rate of 0 sccm to 100 sccm; supplying argon (Ar) gas into the chamber at a flow rate of 0 sccm to 100 sccm; supplying borazine gas into the chamber at a flow rate of 0.01 sccm to 1 sccm; and The pressure in the chamber was maintained at 0.01 Torr to 1 Torr.

17. The method of claim 15, wherein growing the hexagonal boron nitride is performed by inductively coupled plasma chemical vapor deposition.

18. The method according to claim 15, further comprising: Prior to growing the hexagonal boron nitride, contaminants are removed from the surface of the catalytic metal.

19. The method according to claim 15, wherein The nitrogen source and the boron source include at least one of borazine, 1,3,5-trimethylborazine, 2,4,6-trimethylborazine, aminoborane, 2,4,6-trichloroborazine, B-tris(methylamino)borazine and ammonia borane.

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