Crystal orientation substrate having crystal orientation layer with thickness-dependent crystal structure and article comprising same

Abstract

The present invention relates to a crystal orientation substrate having a crystal orientation layer with a thickness-dependent crystal structure, and an article comprising same. More specifically, the crystal orientation substrate comprises: a base substrate; and a crystal orientation layer having a thickness-dependent crystal structure, wherein the crystal orientation layer has a body-centered cubic (BCC) structure or a face-centered cubic (FCC) structure at a thickness less than a critical thickness and a hexagonal close-packed (HCP) structure at a thickness equal to or greater than the critical thickness, the critical thickness is a thickness at which the Gibbs free energy per thickness of the crystal orientation layer has a maximum value, and the Gibbs free energy (G) satisfies the following Relational Expression 1: [Relational Expression 1] G=A(-Sb + Uf* x) where x is the thickness of the crystal orientation layer, A is the cross-sectional area of the substrate, Sb is the interface free energy per unit area of the base substrate / crystal orientation layer, and Uf is the Gibbs free energy per unit volume of the crystal orientation layer.

Description

Crystal orientation substrate having a crystal orientation layer having a thickness-dependent crystal structure and an article including the same

[0001] The present invention relates to a crystal orientation substrate having a crystal orientation layer having a thickness-dependent crystal structure and an article comprising the same.

[0002]

[0003] Epitaxial deposition refers to the deposition of a thin film having the same or similar crystal structure onto a substrate having a specific crystal structure. Such epitaxial deposition can be divided into homoepitaxy, where the substrate and the deposited layer are composed of the same material, and heteroepitaxy, where the substrate and the deposited layer are composed of different materials.

[0004] In this process, the deposited layer (epitaxial layer) grows aligned with the crystal structure of the substrate. In other words, since epitaxial deposition is controlled so that the crystal structure between the substrate and the deposited layer matches, the crystal structure, composition, and surface treatment state of the substrate have a significant impact on the deposition result.

[0005] In particular, the difference in lattice structure between the substrate and the epitaxial layer is important in epitaxial growth for preventing defects, improving growth quality, controlling stress, and promoting uniform growth. First, if the difference in lattice structure and lattice constant is large, stress can occur in the epitaxial layer, leading to defects and affecting the performance and reliability of the device. Furthermore, the more similar the lattice structures of the substrate and the epitaxial layer are, the higher the quality of crystal growth becomes, enabling the fabrication of high-quality thin films. Conversely, lattice mismatch can cause tensile or compressive stress depending on the difference in lattice constants, affecting the physical properties of the epitaxial layer and directly impacting device performance. In other words, when the lattice structures of the substrate and the epitaxial layer are similar, more uniform and stable growth is possible, thereby improving the uniformity and reproducibility of the device. Therefore, by developing various substrate-epitaxial layer combinations considering lattice matching, high-quality thin films can be fabricated and applied to various devices.

[0006] As such, during epitaxial deposition, a material with a cubic crystal structure can be deposited on a substrate with a cubic crystal structure, but there is a limit to the amount of material that can be deposited on a substrate with a hexagonal crystal structure, such as a material having a hexagonal crystal structure or a {111} plane of a cubic crystal structure.

[0007] For example, titanium has a hexagonal crystal structure at room temperature, but a ductile body-centered cubic crystal structure due to high deposition temperature, low deposition pressure, and a fast deposition rate. In other words, in the case of titanium thin films, the deposition layer can be controlled by adjusting deposition conditions such as deposition temperature, deposition gas ratio, and substrate temperature. However, there is a problem in that it is very difficult to precisely control the crystal orientation of the epitaxially deposited layer by direct growth.

[0008] Meanwhile, Gibbs free energy (G) is a thermodynamic function that combines the enthalpy (H) and entropy (S) of a system, and is defined by the following equation (where T is the absolute temperature).

[0009] G=H―TS

[0010] This equation implies that the free energy of a system plays a crucial role in determining the stability of the microstructure, and in the case of epitaxy deposition, growth occurs in a direction that minimizes the system's energy. In other words, since it grows into a stable crystal structure with low Gibbs free energy, controlling the degree of crystallization and nucleation allows for the possibility of crystal structure transitions. That is, it becomes possible for a transition from BCC to HCP to occur.

[0011]

[0012] Accordingly, the inventors of the present invention, after making efforts to develop a crystal orientation substrate capable of determining the crystal orientation during epitaxial growth by direct growth, developed a crystal orientation substrate having a crystal orientation layer with a thickness-dependent crystal structure by controlling the Gibbs free energy by controlling the thickness of the deposited layer during deposition formation, and completed the present invention.

[0013]

[0014] The present invention has as a technical problem to solve the issue of providing a crystal orientation substrate having a crystal orientation layer with a thickness-dependent crystal structure.

[0015] In addition, the present invention has another technical problem to solve by providing a graphene stacked structure including the crystal orientation substrate.

[0016] In addition, the present invention has as another technical problem to solve providing a semiconductor device including the crystal orientation substrate.

[0017] In addition, the present invention has as another technical problem to solve the issue of providing an electrical and electronic device comprising the crystal orientation substrate or graphene stacked structure.

[0018]

[0019] In order to solve the above technical problem, the present invention,

[0020] base substrate; and

[0021] It comprises a crystal orientation layer having a thickness-dependent crystal structure, and

[0022] The crystal orientation layer has a body-centered cubic (BCC) or body-centered cubic (FCC) structure below a critical thickness, and a hexagonal close-packed (HCP) structure above a critical thickness.

[0023] The present invention provides a crystal orientation substrate characterized in that the above critical thickness has a maximum value of Gibbs free energy per thickness of the crystal orientation layer, and the Gibbs free energy (G) satisfies the following relationship 1:

[0024] [Relationship 1]

[0025] G=A(-S b + U f * x)

[0026] (wherein in the above Equation 1, x is the thickness of the crystal orientation layer, A is the cross-sectional area of ​​the substrate, and

[0027] S b ε is the free energy at the base substrate / crystal orientation layer interface per unit area, U f is the Gibbs free energy per unit volume of the crystal orientation layer.

[0028] In the present invention, above the critical thickness, the Gibbs free energy (G) satisfies the following relationship 2:

[0029] [Relationship 2]

[0030] G=A{-S b + △E + U h * (xT c )}

[0031] (wherein in the above Equation 2, x is the thickness of the crystal orientation layer, T cis the critical thickness of the crystal orientation layer, A is the cross-sectional area of ​​the substrate, and

[0032] S b ε is the free energy at the base substrate / crystal orientation layer interface per unit area, U f ε is the Gibbs free energy per unit volume of the crystal orientation layer up to the critical thickness, ΔE is the energy per unit area required for the energy barrier for phase transitions or defect interface rearrangement, and U h is the Gibbs free energy per unit volume of a crystal orientation layer greater than the critical thickness.

[0033] In addition, the present invention is characterized in that the base substrate satisfies the following relationship 4 regarding crystal orientation at the grain boundaries:

[0034] [Relationship 4]

[0035] 5˚ < FWHM2 < 10˚

[0036] (However, FWHM2 is the full width at half maximum of the misorientation angle distribution curve at the grain boundaries of the base substrate.)

[0037] In addition, the present invention is characterized in that the base substrate is a metal or metal oxide substrate, and the crystal orientation layer is a titanium, cobalt, or zirconium thin film.

[0038] In addition, to solve the aforementioned other technical problems, the present invention

[0039] The present invention provides a graphene stacked structure characterized by comprising: a crystal orientation substrate as described above; and a graphene layer formed by epitaxial growth on the substrate.

[0040] In the present invention, a protective thin film layer is further provided in which a protective metal is epitaxially deposited and formed on the upper surface of the crystal orientation substrate, and

[0041] The above protective metal is characterized by being a metal with a lattice constant difference of less than 10% with graphene.

[0042] In addition, the present invention is characterized by further including a metal thin film layer formed by epitaxially depositing and forming one or more alloys selected from Cu, Ni, and Ag on the graphene layer.

[0043] In addition, the present invention is characterized by having a multilayer stacked structure in which the graphene layer and the metal thin film layer are sequentially repeated n times on the metal thin film layer.

[0044] In addition, to solve the aforementioned other technical problem, the present invention provides a semiconductor device comprising the crystal orientation substrate described above.

[0045] In addition, to solve the aforementioned other technical problem, the present invention provides an electrical and electronic device comprising the crystal orientation substrate or graphene stacked structure described above.

[0046]

[0047] According to the crystal orientation substrate of the present invention, a crystal orientation substrate having a face-centered cubic, body-centered cubic, or hexagonal close-packed crystal structure is provided, comprising a crystal orientation layer having a thickness-dependent crystal structure. Accordingly, the present invention has the effect of enabling the selective deposition of materials having various crystal structures without being limited by the crystal structure of the substrate.

[0048] The crystal orientation substrate of the present invention enables various material combinations by controlling the crystal structure as needed, and thereby can be applied to various fields such as high-performance semiconductors, optoelectronic devices, and graphene devices.

[0049]

[0050] Figure 1 shows a crystal orientation substrate according to the present invention.

[0051] Figure 2 shows the Gibbs free energy according to the thickness of the crystal orientation layer of the crystal orientation substrate of the present invention.

[0052] Figure 3 shows a deposition process of a crystal orientation layer (above) according to one embodiment of the present invention and a crystal structure of the crystal orientation layer according to the deposition thickness.

[0053] Figure 4 shows the analysis results of a Ti crystal orientation layer with a critical thickness or greater according to one embodiment of the present invention.

[0054] Figure 5 shows the FFT analysis results when copper is deposited on a crystal orientation substrate with a thickness greater than or equal to a critical thickness according to one embodiment of the present invention.

[0055] Figure 6 shows the analysis results of a Ti crystal orientation layer with a thickness less than the critical thickness according to one embodiment of the present invention.

[0056] Figure 7 shows the EDS analysis results when copper is deposited on a crystal orientation substrate with a thickness less than the critical thickness according to one embodiment of the present invention.

[0057] Figure 8 shows the FFT analysis results when copper is deposited on a crystal orientation substrate with a thickness less than the critical thickness according to one embodiment of the present invention.

[0058] Figure 9 shows the EDS analysis results when copper is deposited on a crystal orientation substrate with a critical thickness or greater according to one embodiment of the present invention.

[0059] FIG. 10 shows the process of depositing graphene on a crystal orientation substrate and the results of Raman analysis according to one embodiment of the present invention.

[0060] FIG. 11 shows a graphene stacked structure including a crystal orientation substrate of the present invention.

[0061]

[0062] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0063] The degree of orientation of a crystal described in this specification refers to the degree to which the orientation axes of the grains in a polycrystalline structure coincide with one another, and a grain refers to each individual crystal within the polycrystalline structure.

[0064] Furthermore, throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0065]

[0066] FIG. 1 shows a crystal orientation substrate according to the present invention,

[0067] In one embodiment, the present invention comprises a base substrate (100); and a crystal orientation layer (200) having a thickness-dependent crystal structure, wherein the crystal orientation layer has a body-centered cubic (BCC) or face-centered cubic (FCC) structure below a critical thickness, and a hexagonal close-packed (HCP) structure above a critical thickness.

[0068] That is, referring to FIG. 1(a), in the case of a crystal orientation substrate in which a crystal orientation layer is deposited to a thickness less than critical in the present invention, a base substrate (100) and a crystal orientation layer (210) having a cubic crystal structure are sequentially stacked to form a structure. Accordingly, the material deposited on this crystal orientation layer grows in the {001} direction.

[0069] Also, referring to FIG. 1(b), a crystal orientation substrate having a crystal orientation layer deposited with a critical thickness or greater is formed in a structure in which a base substrate (100), a crystal orientation layer (210) having a cubic crystal structure, and a crystal orientation layer (220) having a hexagonal crystal structure are sequentially stacked. Accordingly, the material deposited on the crystal orientation layer grows in the {111} direction.

[0070] As such, according to the present invention, since the crystal orientation layer has a thickness-dependent crystal structure, the crystal orientation can be controlled by controlling the thickness. In this regard, FIG. 2 shows the Gibbs free energy according to the thickness of the crystal orientation layer of the crystal orientation substrate of the present invention. The crystal orientation layer having a thickness-dependent crystal structure of the present invention controls the crystal structure by controlling the interface energy between the crystal orientation layer and the substrate, the free energy according to the crystal structure, and the energy barrier or free energy due to dislocation interface rearrangement due to phase transition by controlling the thickness when depositing the crystal orientation layer on a base substrate.

[0071] That is, when the crystal orientation layer is deposited, if the thickness is below the critical thickness, the interface energy with the substrate and the Gibbs free energy due to the FCC phase increase, and since the crystal is not stabilized, the face-centered cubic structure is maintained. At this time, the Gibbs free energy per thickness of the crystal orientation layer is determined by the free energy at the interface between the crystal orientation layer and the base substrate, the Gibbs free energy per unit volume of the crystal orientation layer, and the area of ​​the base substrate. The critical thickness is characterized by the Gibbs free energy per thickness of the crystal orientation layer having a maximum value, and the Gibbs free energy (G) satisfying the following Equation 1:

[0072] [Relationship 1]

[0073] G=A(-S b + U f * x)

[0074] (wherein in Equation 1 above, x is the thickness of the crystal orientation layer, A is the cross-sectional area of ​​the substrate, and

[0075] S b ε is the free energy at the base substrate / crystal orientation layer interface per unit area, U f is the Gibbs free energy per unit volume of the crystal orientation layer.

[0076] In addition, above the above critical thickness, the crystal structure stabilizes as the Gibbs free energy per thickness of the crystal orientation layer decreases, and the crystal orientation layer acquires a hexagonal close-packed crystal structure. Preferably, above the above critical thickness, the Gibbs free energy (G) satisfies the following Equation 2:

[0077] [Relationship 2]

[0078] G=A{-S b + △E + U h * (xT c )}

[0079] (wherein in Equation 2 above, x is the thickness of the crystal orientation layer, T c is the critical thickness of the crystal orientation layer, A is the cross-sectional area of ​​the substrate, and

[0080] S b ε is the free energy at the base substrate / crystal orientation layer interface per unit area, U f ε is the Gibbs free energy per unit volume of the crystal orientation layer up to the critical thickness, ΔE is the energy per unit area required for the energy barrier for phase transitions or defect interface rearrangement, and U h is the Gibbs free energy per unit volume of a crystal orientation layer greater than the critical thickness.

[0081] At this time, the base substrate may be a metal or metal oxide substrate. Preferably, the metal may be any one of copper, nickel, cadmium, magnesium, aluminum, steel, and stainless steel, or an alloy thereof. In addition, it is also possible to use one or more of IBAD (Ion Beam Assisted Deposition), RABiTS (Rolling Assisted Biaxially Textured Substrate), and Hastelloy.

[0082] In addition, the metal oxides include tin (Sn) oxide, antimony (Sb), niobium (Nb) or fluorine-doped tin (Sn) oxide, indium (In) oxide, tin-doped indium (In) oxide, zinc (Zn) oxide, aluminum (Al), boron (B), gallium (Ga), hydrogen (H), indium (In), yttrium (Y), titanium (Ti), silicon (Si) or tin (Sn)-doped zinc (Zn) oxide, magnesium (Mg) oxide, cadmium (Cd) oxide, magnesium-zinc (MgZn) oxide, indium-zinc (InZn) oxide, copper-aluminum (CuAl) oxide, silver (Ag) oxide, gallium (Ga) oxide, zinc-tin oxide (ZnSnO), titanium oxide (TiO2) and zinc-indium-tin (ZIS) oxide, nickel (Ni) oxide, One or more of rhodium (Rh) oxide, ruthenium (Ru) oxide, iridium (Ir) oxide, copper (Cu) oxide, cobalt (Co) oxide, tungsten (W) oxide, and titanium (Ti) oxide can be selected and used as a substrate.

[0083] In addition, the crystal orientation layer may be formed from a metal capable of allotropic transformation, in which the crystal structure of the metal changes due to temperature or pressure, etc. Preferably, it may be formed from any one selected from titanium, cobalt, zirconium, or hafnium.

[0084] For example, titanium, zirconium, and hafnium have a stable hexagonal crystal structure at room temperature and transition to a body-centered cubic (BCC) crystal structure at high temperatures, while cobalt generally has a stable hexagonal crystal structure but transitions to a face-centered cubic (FCC) crystal structure under specific conditions. In this case, when transitioning to a cubic crystal structure, the crystallization of the deposited metal can be promoted to minimize the difference in lattice structure between the base substrate and the deposited metal; thus, thin films with desired properties can be obtained through crystal plane control.

[0085] Therefore, when such a metal is deposited to form a crystal orientation layer, a crystal orientation layer with a cubic crystal structure is formed up to a critical thickness where the Gibbs free energy reaches a maximum value, and as it is deposited beyond the critical thickness, the Gibbs free energy gradually decreases, and a crystal orientation layer with a stable hexagonal crystal structure is formed.

[0086] In addition, when depositing a crystal orientation layer on the base substrate, the deposition method may include chemical vapor deposition (CVD) using heat or plasma, physical vapor deposition (PVD) using an electron beam or sputtering, atomic layer deposition (ALD), spin-on-glass (SOG), thermal evaporation, plating, or various other methods. Preferably, sputtering deposition may be used.

[0087] Figure 3 illustrates the formation of a Ti crystal orientation layer by depositing Ti on an IBAD-MgO base substrate by sputtering. Specifically, when Ti is deposited on an IBAD-MgO substrate, the crystal structure of Ti transitions from a cubic (FCC) structure to a hexagonal (HCP) structure depending on the thickness. As described above, although an FCC structure is generally not observed in Ti, a thin film having an FCC crystal structure is formed by controlling the crystal planes as the Ti crystallizes to align its lattice with the MgO substrate while being deposited on the MgO substrate. That is, when Ti is deposited with a thickness of 5 nm or less, it has an FCC crystal structure, and if copper is deposited on this thin film, it grows in the {001} direction; however, if the Ti thickness is 5 nm or more, an HCP crystal structure appears, and the copper grows in the {111} direction. In this way, by controlling the thickness of the Ti thin film under the same deposition conditions, it becomes possible to freely control FCC and HCP structures based on atomic arrangement.

[0088] The critical thickness is determined by the following relationship.

[0089]

[0090] U f ≈3.0×10 8 J / m 3, . U h ≈2.5×10 8 J / m 3 . S b ≈0.5 J / m 2 . ΔE≈0.20 J / m 2 When the value is substituted, the critical thickness is obtained as 4 nm. It can be seen that a value almost identical to the experimental value is obtained.

[0091] In addition, in the present invention, preferably, the crystal orientation at the grain boundaries of the crystal orientation layer satisfies the following relationship 3:

[0092] [Relationship 3]

[0093] 0˚〈 FWHM1〈 3˚

[0094] (However, FWHM1 is the full width at half maximum of the distribution curve of the misorientation angle at the grain boundaries of the crystal orientation layer.

[0095] In other words, the crystal orientation substrate of the present invention controls the crystal structure by controlling the free energy of the system through controlling the degree of crystallization and nucleation of the crystal orientation layer during the formation of the crystal orientation layer, and enables rapid crystal orientation to achieve a crystal orientation at the level of a single crystal.

[0096] At this time, in order to control the crystal orientation of the crystal orientation layer, it is preferable that the base substrate satisfies the crystal orientation at the grain boundaries of the following Equation 4:

[0097] [Relationship 4]

[0098] 5˚ < FWHM2 < 10˚

[0099] (However, FWHM2 is the full width at half maximum of the misorientation angle distribution curve at the grain boundaries of the base substrate.)

[0100] In this regard, Figure 4 shows the thin film cross-sectional structure of a sample in which a Cu layer is sequentially stacked after a Ti layer of 5 nm or more is deposited on an IBAD-MgO substrate using sputtering deposition, as well as the results of ESD analysis, 2D X-ray diffraction analysis, and FE-SEM analysis.

[0101] First, examining the EDS analysis results, when a Ti layer of 50 nm or larger is deposited, a Ti layer is formed with a crystal orientation of the {002} plane on the top surface due to the hexagonal crystal structure. Subsequently, when Cu is deposited and grown, a Cu layer is formed in the {111} direction. This can be confirmed through X-ray 2 theta-scan diffraction analysis, which reveals Ti{002} and Cu{111} peaks, as well as through GADDS area detector analysis. Additionally, a Phi scan of the Cu{002} plane indicates a full width at half maximum (FWHM) of 1.1 degrees, suggesting that the crystal axes are aligned at a single-crystal level. FE-SEM analysis of the copper thin film surface confirms a very clean surface free of grain boundaries and defects. In particular, the IBAD-MgO substrate is a substrate with a full width at half maximum (FWHM) of 6 to 8 degrees, and it can be confirmed that when a Ti layer, which is the crystal orientation layer, is deposited using this as a base substrate, the FWHM is 1.1 degrees. That is, when the Ti layer is deposited, crystal orientation occurs at a rapid rate, aligning to a single-crystal level, and the layer is deposited beyond a critical thickness.

[0102] Figure 5 shows the TEM FFT results of the MgO / Ti / Cu thin film of Figure 4. By analyzing the cross-section of the MgO / Ti / Cu thin film, it can be confirmed that a Ti FCC crystal structure is formed when the Ti thickness on the MgO substrate is 5 nm or less, and a Ti HCP crystal structure is formed when it is 5 nm or more.

[0103] Figure 6 shows the thin film cross-sectional structure and the results of two-dimensional X-ray diffraction analysis and FE-SEM analysis of a sample in which a Ti layer is deposited to a thickness of less than 5 nm and a Cu layer is sequentially stacked using sputtering deposition on an IBAD-MgO substrate.

[0104] Based on this, when a Ti layer of less than 5 nm is deposited, a Ti layer is formed with a crystal orientation of the {001} plane on the top, as it possesses a cubic crystal structure. Subsequently, when Cu is deposited, a Cu layer is formed as Cu grows in the {002} direction. This can be confirmed through X-ray 2 theta scan diffraction analysis, which reveals the Cu{002} peak, and also through GADDS Area detector analysis. Furthermore, a Cu{111} plane Phi scan indicates that the full width at half maximum (FWHM) is 1.1 degrees, which suggests that the crystal axes are aligned at a single-crystal level. FE-SEM analysis of the copper thin film surface reveals crystal grains of several tens of nanometers in size. As described above, when a Ti layer, which serves as the crystal orientation layer, is deposited to a thickness less than the critical thickness using an IBAD-MgO substrate with a FWHM of 6 to 8 degrees as the base substrate, it can be confirmed that the FWHM is 1.1 degrees. In other words, it can be confirmed that during the Ti layer deposition, the deposition layer was formed with rapid crystal orientation and alignment at the single-crystal level.

[0105] Figures 7 and 8 show the TEM EDS analysis results and TEM FFT results of the Cu layer deposited on the crystal orientation substrate of Figure 6. Figure 7 shows that the TEM EDS measurement results indicate that Ti has grown to a thickness of 5 nm on the MgO substrate. Figure 8 shows that the growth was made of Cu{002} as measured by the GADDS Area Detector, and the TEM measurement results confirmed that the thickness of Ti is 5 nm and the crystal structure is an FCC cubic crystal structure.

[0106] Figure 9 shows the results of EBSD analysis performed after depositing 50 nm of Ti and then depositing copper on a nickel-copper metal foil (Ni-30 at%, copper-70 at%) substrate. It indicates that the metal foil has an FCC crystal structure and that the crystal grains are oriented in the {001} direction perpendicular to the substrate. Additionally, when Ti was deposited on this substrate, a Ti FCC {001} / Ti HCP {001} thin film was formed, and it can be seen that Cu grew in the {111} direction on the Ti HCP {001} thin film. This demonstrates that the crystal plane perpendicular to the substrate of the foil, which is composed of copper, nickel, and copper-nickel alloy, can be converted to {111}. This substrate can be utilized for graphene thin film deposition.

[0107]

[0108] Accordingly, in another aspect, the present invention relates to a graphene stacked structure comprising: a crystal orientation substrate described above; and a graphene layer formed by epitaxial growth on the substrate. The crystal plane of the graphene layer is controlled by the crystal orientation substrate, so that it has a crystal plane that is a {001} plane or a {111} plane depending on the desired thickness of the crystal orientation substrate, thereby enabling the appropriate manufacture of a graphene conductor as needed.

[0109] FIG. 10 shows the results of Raman analysis performed by depositing Ti as a crystal orientation layer exceeding a critical thickness on an IBAD-MgO substrate, depositing graphene thereon using a drum chamber, and then analyzing the results. Although the intensity varies depending on the measurement positions (1, 2, 3), it is 1593 cm⁻¹. -1 , 2659 cm -1 It can be confirmed that graphene was deposited well by showing a peak at.

[0110] Preferably, a protective thin film layer may be further included in which a protective metal is epitaxially deposited and formed on the upper surface of the crystal-oriented substrate described above. That is, a protective thin film layer made of a protective metal may be formed on the upper surface of the crystal-oriented substrate, and a graphene layer may be grown thereon. At this time, the protective metal may be a metal having a lattice constant difference of less than 10% with respect to graphene, not reacting with the upper or lower material at high temperatures, and having low carbon solubility. For example, the protective metal may be an alkali metal such as Cu, Ag, or Li, Na. Such a protective metal can promote the growth of graphene due to its low carbon solubility while having a small difference in lattice constant with respect to graphene, and can form a graphene layer that is crystal-oriented in the same way as the crystal orientation of the substrate.

[0111] In addition, preferably, a metal thin film layer may be further included in which one or more alloys selected from Cu, Ni, and Ag, which are cubic metals, are epitaxially deposited and formed on the graphene layer described above.

[0112]

[0113] FIG. 11 shows a graphene stacked structure including a crystal orientation substrate of the present invention, wherein a graphene layer (30) and a metal thin film layer (40) can be configured to be repeatedly stacked on the crystal orientation substrate (10) described above. With reference to this, the crystal plane of the graphene layer (30) is controlled by the crystal orientation substrate (10) so that, depending on the desired thickness of the crystal orientation substrate, (a) the crystal plane is a {001} plane or (b) a {111} plane, and then a graphene conductor can be manufactured by appropriately adjusting the number of stacking layers as needed. Therefore, more preferably, a multilayer stacked structure in which the graphene layer and the metal thin film layer are sequentially repeated n times on the metal thin film layer can be formed to have an appropriate thickness while maintaining the same crystal orientation of the crystal plane through epitaxial growth. Accordingly, it can be applied to various electrical and electronic devices.

[0114]

[0115] In addition, the crystal orientation substrate of the present invention can exhibit excellent crystal orientation regardless of the type of base substrate, and thus can be applied to flexible substrates, large-area substrates, etc., and is expected to provide excellent functionality to superconducting wires, semiconductor devices, electrical and electronic devices, etc.

[0116]

[0117] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not to limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by such embodiments. The scope of protection of the present invention shall be interpreted by the claims, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

[0118]

[0119] The present invention can provide a crystal orientation substrate having a face-centered cubic, body-centered cubic, or hexagonal close-packed crystal structure, comprising a crystal orientation layer having a thickness-dependent crystal structure, and thereby has the feature of being able to selectively deposit materials having various crystal structures.

[0120] Therefore, based on the ability to handle various functional thin film materials, materials with a wide range of crystal structures, such as semiconductor materials (diamond structure), metal thin films (FCC, BCC), ferroelectrics / piezoelectrics (perovskite structure), and magnetic materials (FCC, BCC, HCP), can be epitaxially grown on a single platform, which has the characteristic of greatly increasing development flexibility.

[0121] Furthermore, by minimizing interfacial defects and stress, the interface can be formed with an optimal crystal structure depending on the thickness of the deposited thin film. Additionally, since it can effectively reduce internal stress caused by lattice mismatch and differences in thermal expansion coefficients during hetero-epitaxy growth, thereby improving the lifespan and reliability of the device, it can be utilized in various industrial fields such as high-performance semiconductors, optoelectronic devices, and graphene devices.

Claims

1. Base substrate; and It comprises a crystal orientation layer having a thickness-dependent crystal structure, and The crystal orientation layer has a body-centered cubic or face-centered cubic cubic structure below a critical thickness and a hexagonal structure above a critical thickness, and A crystal orientation substrate characterized in that the above critical thickness has a maximum value of Gibbs free energy per thickness of the crystal orientation layer, and the Gibbs free energy (G) satisfies the following relationship 1: [Relationship 1] G=A(-S b + U f * x) (wherein in the above Equation 1, x is the thickness of the crystal orientation layer, A is the cross-sectional area of ​​the substrate, and S b ε is the free energy at the base substrate / crystal orientation layer interface per unit area, U f is the Gibbs free energy per unit volume of the crystal orientation layer.

2. In Paragraph 1, A crystal orientation substrate characterized in that, above the critical thickness, the Gibbs free energy (G) satisfies the following relationship 2: [Relationship 2] G=A{-S b + △E + U h * (x-T c )} (wherein in the above Equation 2, x is the thickness of the crystal orientation layer, T c is the critical thickness of the crystal orientation layer, A is the cross-sectional area of ​​the substrate, and S b ε is the free energy at the base substrate / crystal orientation layer interface per unit area, U f ε is the Gibbs free energy per unit volume of the crystal orientation layer up to the critical thickness, ΔE is the energy per unit area required for the energy barrier for phase transitions or defect interface rearrangement, and U h is the Gibbs free energy per unit volume of a crystal orientation layer greater than the critical thickness.

3. In Paragraph 1, The above base substrate is a metal or metal oxide substrate, and A crystal orientation substrate characterized in that the crystal orientation layer is a titanium, cobalt, or zirconium thin film.

4. In Paragraph 1, A crystal orientation substrate characterized in that the crystal orientation at the grain boundaries of the crystal orientation layer satisfies the following relationship 3: [Relationship 3] 0˚〈 FWHM1〈 3˚ (However, FWHM1 is the full width at half maximum of the distribution curve of the misorientation angle at the grain boundaries of the crystal orientation layer.) 5. In Paragraph 1, A crystal orientation substrate characterized in that the base substrate satisfies the following relationship 4 for crystal orientation at the grain boundaries: [Relationship 4] 5˚〈 FWHM2〈 10˚ (However, FWHM2 is the full width at half maximum of the misorientation angle distribution curve at the grain boundaries of the base substrate.) 6. A crystal orientation substrate according to any one of claims 1 to 5 above; and A graphene stacked structure characterized by comprising a graphene layer formed by epitaxial growth on the substrate.

7. In Paragraph 6, The above crystal orientation substrate further comprises a protective thin film layer having a protective metal epitaxially deposited and formed on its upper surface, and A graphene stacked structure characterized in that the protective metal is a metal having a lattice constant difference of less than 10% with respect to graphene.

8. In Paragraph 6, A graphene stacked structure characterized by further comprising a metal thin film layer formed by epitaxially depositing and forming one or more alloys selected from Cu, Ni, and Ag on the graphene layer.

9. In Paragraph 8, A graphene stacked structure characterized by having a multilayer stacked structure in which the graphene layer and the metal thin film layer are sequentially repeated n times on the metal thin film layer.

10. A semiconductor device comprising a crystal orientation substrate according to any one of claims 1 to 5.

11. An electrical and electronic device comprising a crystal orientation substrate according to any one of claims 1 to 5.

12. An electrical and electronic device comprising a graphene stacked structure according to claim 6.

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