A method for manufacturing a single-crystal copper thin film in which grain boundaries are suppressed, including the nonlinear Hall effect and hole carrier-dominant transport phenomena, a single-crystal copper thin film manufactured using the same, and a single-crystal copper thin film semiconductor.

Abstract

This invention relates to single-crystal copper thin films and single-crystal copper thin-film semiconductors that utilize the phenomenon in which holes, rather than electrons, become carriers when grain boundaries (GB) are removed in copper thin films with a thickness of 200 nm or less. More specifically, it relates to copper thin films and single-crystal copper thin-film semiconductors whose electrical properties change to a p-type semiconductor-like form under specific conditions. This single-crystal copper thin film, which includes a nonlinear Hall effect and a hole carrier-dominant transport phenomenon in a two-dimensional single-crystal thin film with suppressed grain boundaries, includes single-crystal copper thin films with a thickness of 200 nm or less and is characterized by suppressed grain boundaries.

Description

[Technical Field]

[0001] This invention relates to single-crystal copper thin films and single-crystal copper thin-film semiconductors that utilize the phenomenon in which holes, rather than electrons, become carriers when grain boundaries (GB, also called crystal grain boundaries) are removed in copper thin films with a thickness of 200 nm or less. More specifically, it relates to copper thin films and single-crystal copper thin-film semiconductors whose electrical properties change to a form similar to a p-type semiconductor under specific conditions. [Background technology]

[0002] It is well known that the carriers in copper are electrons. 23 / cm 3 The electron concentration and 1.72 × 10 -8 Because it exhibits a room-temperature resistance of Ωcm, it has the second highest electrical conductivity after silver (Ag), and is therefore mainly used as an electrode or conductor for carrying electric current, making it difficult to perform functions for special purposes.

[0003] In contrast, depending on its type, semiconductors may have electrons as their primary carrier (n-type) or holes as their primary carrier (p-type). When an n-type semiconductor and a p-type semiconductor are joined to form a pn junction, the current flow becomes asymmetric, which is an important characteristic that allows it to be used as a device.

[0004] If it were possible to achieve both n-type and p-type properties using only copper, it would be a groundbreaking invention that would allow for the simultaneous realization of electrode and device functions using only copper, without the need to introduce semiconductor materials. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The present invention was created to solve the above problems, and its purpose is to manufacture a copper thin film that can achieve n-type and p-type properties using only copper, by changing the shape of the electron orbitals of copper in order to solve the defects that ordinary copper has.

[0006] The technical problems that this invention aims to solve are not limited to those described above, and other unmentioned technical problems can be clearly understood by a person with ordinary skill in the art to which this invention belongs from the following description. [Means for solving the problem]

[0007] (1) Single crystal copper thin film The present invention relates to a two-dimensional single-crystal thin film in which grain boundaries are suppressed, and which includes a single-crystal copper thin film containing the nonlinear Hall effect and hole carrier-dominant transport phenomena. This single-crystal copper thin film includes a single-crystal copper thin film with a thickness of 200 nm or less, and is characterized in that grain boundaries are suppressed.

[0008] Furthermore, the single-crystal copper thin film is characterized by exhibiting nonlinear behavior in its Hall resistance in response to a magnetic field.

[0009] Furthermore, the single-crystal copper thin film is characterized by being obtained by growing copper on a sapphire substrate using atomic sputtering epitaxial growth (ASE).

[0010] Furthermore, the single-crystal copper thin film is characterized in that its Hall resistance exhibits nonlinear behavior as the temperature changes.

[0011] (2) Single-crystal copper thin-film semiconductor The single-crystal copper thin-film semiconductor according to the present invention includes a single-crystal copper thin film with a thickness of 200 nm or less, characterized in that the single-crystal copper thin film has suppressed grain boundaries and its electrical properties are changed to p-type.

[0012] Furthermore, the single-crystal copper thin film is characterized by exhibiting nonlinear behavior in its Hall resistance in response to a magnetic field.

[0013] Furthermore, the single-crystal copper thin film is obtained by growing copper on a sapphire substrate by atomic sputtering epitaxial growth (ASE) method.

[0014] Furthermore, the single-crystal copper thin film is characterized in that the hall resistance shows non-linear behavior as the temperature changes.

[0015] (3) Method for manufacturing single-crystal copper thin film It is characterized in that it is manufactured by growing a copper thin film by high-frequency (RF) sputtering of copper under temperature conditions of 160°C to 180°C.

[0016] Also, the initial pressure of the high-frequency (RF) sputtering is -3 Pa to -3 Pa.

[0017] Furthermore, the high-frequency (RF) sputtering is characterized in that it is carried out in an atmosphere of argon (Ar) gas.

[0018] Furthermore, the high-frequency (RF) sputtering is characterized in that it is carried out by injecting argon (Ar) gas to 0.3 Pa to 0.7 Pa to adjust the pressure.

[0019] Furthermore, the high-frequency (RF) output of the high-frequency (RF) sputtering is 23 W to 27 W.

[0020] Furthermore, the rotation speed of the high-frequency (RF) sputtering is 25 RPM to 35 RPM.

Advantages of the Invention

[0021] By addressing the above-mentioned problems, the present invention solves the defects inherent in ordinary copper and, by lengthening the mean free path of electrons, can change the structure of the Fermi surface where existing electrons reside, thereby altering the shape of the electron orbitals.

[0022] Furthermore, the present invention makes it possible to manufacture copper thin films that can achieve n-type and p-type properties using only copper by changing the shape of the electron orbitals of copper. [Brief explanation of the drawing]

[0023] [Figure 1] This graph shows the Hall effect of ordinary copper or three-dimensional (3D) bulk copper. [Figure 2] This is a 3D copper Fermi surface, a ring pattern that induces asymmetric magnetoresistance along the forward (a) and reverse (b) directions of the electric current. [Figure 3] This surface shows the Fermi surface of 2D copper observed using a periodic zone scheme. [Figure 4] (a) is the Fermi surface obtained from a 2D single-crystal copper thin film by angle-resolved photoemission spectroscopy (ARPES) measurement, and (b) is a diagram showing the results measured along the direction of the orange arrow in (a) on the energy axis. [Figure 5] The graphs show the Hall effect of single-crystal copper thin films of various thicknesses. (a) shows the nonlinear Hall effect of a polycrystalline copper film (PCCF) with a thickness of 82 nm, (b) shows the nonlinear Hall effect of a polycrystalline copper film (PCCF) with a thickness of 205 nm, (c) shows the nonlinear Hall effect of a polycrystalline copper film (PCCF) with a thickness of 80 nm, (d) shows the nonlinear Hall effect of a polycrystalline copper film (PCCF) with a thickness of 40 nm, (e) shows the nonlinear Hall effect of a polycrystalline copper film (PCCF) with a thickness of 12 nm, and (f) shows the nonlinear Hall effect of a polycrystalline copper film (PCCF) with a thickness of 10 nm. [Figure 6]The first column shows electron backscatter diffraction (EBSD), mis-orientation lines (second column), Hall effect measurements (third column), and grain boundaries (GB) and twin boundaries (TB) of a 40 nm thick thin film. (a) is a polycrystalline thin film, (b) to (d) are near-single-crystal thin films grown by atomic sputtering epitaxial growth (ASE), with the grain boundaries (GB) controlled differently for comparison, and (e) is a perfect single-crystal thin film with no grain boundaries.

[0024] The terms used herein will be briefly explained, and then the present invention will be described in detail.

[0025] In this invention, while considering the function of the invention, we have selected as many commonly used terms as possible. However, this may vary depending on the intentions of engineers in the field, precedents, the emergence of new technologies, etc. Therefore, the terms used in this invention are not merely names of terms, but are defined based on the meaning of the terms and the overall content of this invention.

[0026] Throughout the specification, if a part is described as "including" a certain component, this means that it may include other components, rather than excluding other components.

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention can be embodied in various different forms and is not limited in any way to the embodiments described herein.

[0028] The specific details of the present invention, including the problems to be solved, the means of solving those problems, and the effects of the invention, are included in the embodiments and drawings described below. The advantages and features of the present invention, as well as the methods for achieving them, will become even clearer when referring to the embodiments described in detail later in conjunction with the accompanying drawings.

[0029] (1) Single crystal copper thin film The single-crystal copper thin film in which grain boundaries are suppressed in a two-dimensional single-crystal thin film according to the present invention includes a single-crystal copper thin film with a thickness of 200 nm or less, characterized in that grain boundaries are suppressed. More specifically, it can be confirmed that a single-crystal copper thin film with a thickness of 40 nm or less shows the best grain boundary suppression effect.

[0030] Furthermore, the single-crystal copper thin film is characterized by exhibiting nonlinear behavior in its Hall resistance in response to a magnetic field.

[0031] Furthermore, the single-crystal copper thin film is characterized by being obtained by growing copper on a sapphire substrate using atomic sputtering epitaxial growth (ASE).

[0032] Furthermore, the single-crystal copper thin film is characterized in that its Hall resistance exhibits nonlinear behavior as the temperature changes.

[0033] (2) Single-crystal copper thin-film semiconductor The single-crystal copper thin-film semiconductor according to the present invention includes a single-crystal copper thin film with a thickness of 200 nm or less, characterized in that the grain boundary is suppressed and the electrical properties are changed to p-type. More specifically, it can be confirmed that a single-crystal copper thin film with a thickness of 40 nm or less exhibits the best grain boundary suppression effect.

[0034] Furthermore, the single-crystal copper thin film is characterized by exhibiting nonlinear behavior in its Hall resistance in response to a magnetic field.

[0035] Furthermore, the single-crystal copper thin film is characterized by being obtained by growing copper on a sapphire substrate using atomic sputtering epitaxial growth (ASE).

[0036] Furthermore, the single-crystal copper thin film is characterized in that its Hall resistance exhibits nonlinear behavior as the temperature changes.

[0037] (3) Method for manufacturing single-crystal copper thin film The product is characterized by being manufactured by growing a thin copper film by radio frequency (RF) sputtering under temperature conditions of 160°C to 180°C. More specifically, it is preferable to grow the thin copper film by radio frequency (RF) sputtering under temperature conditions of 170°C.

[0038] The initial pressure for the aforementioned high-frequency (RF) sputtering is 2.0 × 10⁻⁶ -3 Pa~2.5×10 -3 It is characterized by being Pa. More specifically, 2.3 × 10 -3 Pa is preferable.

[0039] Furthermore, the high-frequency (RF) sputtering is characterized by being performed in an argon (Ar) gas atmosphere.

[0040] Furthermore, the aforementioned radio frequency (RF) sputtering is characterized by adjusting the pressure by injecting argon (Ar) gas to 0.3 Pa to 0.7 Pa. More specifically, 0.5 Pa is preferred.

[0041] Furthermore, the high-frequency (RF) output of the aforementioned high-frequency (RF) sputtering is characterized by being 23W to 27W. More specifically, 25W is preferred.

[0042] Furthermore, the rotational speed of the high-frequency (RF) sputtering is characterized by being 25 RPM to 35 RPM. More specifically, 30 RPM is preferred.

[0043] The present invention will be described in more detail below with reference to the attached drawings.

[0044] This invention relates to a single-crystal copper thin film that utilizes the phenomenon where holes, rather than electrons, become carriers when grain boundaries (GB) are removed in a copper thin film with a thickness of 200 nm or less. More specifically, it relates to a copper thin film whose electrical properties have changed to a form similar to a p-type semiconductor under specific conditions. This invention completely resolves the defects present in ordinary copper and lengthens the mean free path of electrons, thereby changing the structure of the Fermi surface where existing electrons reside and altering the shape of electron orbitals.

[0045] The single-crystal copper thin film in which grain boundaries are suppressed in a two-dimensional single-crystal thin film according to the present invention includes a single-crystal copper thin film with a thickness of 200 nm or less, characterized in that grain boundaries (hereinafter referred to as GB) are suppressed.

[0046] Furthermore, the single-crystal copper thin film is characterized by exhibiting nonlinear behavior in its Hall resistance in response to a magnetic field.

[0047] Furthermore, the single-crystal copper thin film is characterized by being obtained by growing copper on a sapphire substrate using the atomic sputtering epitaxy (ASE) method.

[0048] Generally, when the Hall effect in copper is measured, it appears linearly. This is because there is only one carrier, meaning that the Hall resistance increases linearly with increasing magnetic field and does not change significantly with temperature. Figure 1 shows the Hall effect of ordinary copper or three-dimensional bulk copper, and as shown in the figure, it can be confirmed that the Hall resistance increases linearly with increasing magnetic field.

[0049] Solid-state electronic devices, including transistors, diodes, and various sensors, utilize the flow and control of conduction electrons in semiconductor channels and metal electrodes. Among the various properties of materials, the electronic band structure near the Fermi surface determines the behavior of conduction electrons, which is a core function exploited in the application and design of devices. Thus, the polarity, density, and mobility of charge carriers are manipulated and optimized for semiconductors. However, effective design of electronic properties has not been applied to other important electronic components, such as those containing noble metals like copper (Cu), which conceptually limits the overall potential of materials for new devices.

[0050] The Fermi surface of metals is overwhelmed by random scattering at numerous defects such as GBs during transport. GBs are ~10 2 μm -2 (10 10 cm -2It is unavoidable because it forms at densities above 10 nm. Electron and phonon transport is reported to be critically influenced by GB, especially when the mean free path (MFP) of the transport medium is longer than the distance between GBs. Furthermore, the miniaturization of modern electronic products is remarkable, and with this, the miniaturization of electronic elements is progressing more and more, leading to a rapid increase in demand for two-dimensional (2D) electronic materials, including metals. Therefore, the synthesis of single-crystal metals in two-dimensional (2D) shapes is an interesting challenge. Nucleation in the early growth stage produces countless separated particles. Although considerable effort has been made to minimize GB in two-dimensional (2D) metals, it has not been possible to completely suppress GB, especially in the case of large-scale noble metals (e.g., copper (Cu) and gold (Au)) with thicknesses of up to 10 nm. GB formed in the early growth stage causes electron scattering, resulting in the loss of intrinsic properties. For example, the resistivity of noble metals increases as the thickness decreases, and this is particularly noticeable at the two-dimensional limit. Despite the significant increase in interest in two-dimensional (2D) materials following the discovery of graphene, the two-dimensional (2D) properties of novel metals remain largely unexplored. Therefore, thickness control is employed to solve engineering problems, such as achieving high conductivity with minimal metal content for device fabrication. The main physical causes of the thickness-dependent resistivity change, along with the properties of graphene-bandwidth (GB), are the modified conduction mechanisms of metals. In the absence of GB, and when the thickness is even lower than the mean free path (MFP) of the transport medium, unconventional transport of metals can be considered.

[0051] In contrast, in the single-crystal copper thin film according to the present invention, the frequency of collisions between electrons and GB is significantly reduced, the mean free path becomes longer, and by sufficiently circling the outermost edge of the Fermi surface, the electron exhibits hole-like behavior while circling a hole pocket in reciprocal lattice space.

[0052] In ultra-high-purity two-dimensional (2D) copper induced by the combination of the two-dimensional (2D) shape of the single-crystal copper thin film (SCCF) of the present invention and growth without grain bounding (GB), counterintuitive hole carrier-dominant (HCD) transport is exhibited. GB density can be strongly suppressed in two-dimensional (2D) copper fabricated by atomic sputtering epitaxial growth (ASE). In the absence of grain boundaries, another category of geometric features, twin boundaries (TB), can be examined, which, compared to GB, satisfy symmetry and therefore do not hinder electron transport. Strict characterization of the electronic band structure of two-dimensional (2D) copper was performed by structural analysis, angle-resolved photoemission spectroscopy (ARPES) measurements, and hole measurements using fitting analysis of a two-carrier model. Unlike existing copper electron carriers, the suppression of GB in two-dimensional (2D) single-crystal copper thin films (SCCF) indicates hole carrier-dominant (HCD) transport. Theoretically, first-principles calculations and angle-resolved photoemission spectroscopy (ARPES) measurements experimentally explain hole carrier-dominated (HCD) transport in two-dimensional (2D) copper where the GB (gab-bearing) plane is absent, due to the concave shape of the Fermi surface. The intrinsic properties of the transport present a groundbreaking method for manipulating the apparent polarity of charge carriers in metals, based on two-dimensional (2D) GB engineering.

[0053] Figure 2(a) shows the Fermi surface of bulk single-crystal copper, and when the three-dimensional bulk single-crystal copper is made two-dimensional, it shows the pattern shown in Figure 2(b). If copper has an ideal single-crystal structure, electrons will orbit the outermost surface of Figure 2(b), and this can be represented in periodic reciprocal lattice space as shown in Figure 3.

[0054] As shown by the blue circles in Figure 3, electrons orbit in electron orbitals, but electrons orbiting on the outermost orbit pass through the adjacent Fermi surface via an open orbit, and then orbit in a triangular hole orbit. The theoretical calculation results in Figures 2 and 3 are experimentally supported.

[0055] Figure 4(a) accurately experimentally demonstrates the theoretical model of two-dimensional (2D) single-crystal copper predicted in Figure 3. The hexagonal orbits at the bottom of Figure 3(a) represent electron orbitals, while the triangular orbits located on the right or left shoulder represent hole orbitals. Figure 4(b) shows the energy distribution measured in the kx direction along the orange arrow in Figure 4(a), where electron orbitals (blue dotted line) and hole orbitals (yellow dotted line) are clearly observed.

[0056] To understand the intrinsic properties of two-dimensional (2D) copper thin films, the electron band structure of copper at the two-dimensional (2D) limit was calculated. When copper is thinned to the nanometer scale along the spatial coordinates to reach the two-dimensional (2D) limit, quantum constraints reconstruct the normal three-dimensional (3D) Fermi surface as shown in Figure 2(a), and the two-dimensional (2D) subband surface is constructed as shown in Figure 2(b). As a result, a series of two-dimensional (2D) Fermi surfaces are generated. As the copper is thinned along the direction, the unique deformation of the two-dimensional (2D) Fermi surfaces leads to the formation of concave electron bands and hole bands, respectively.

[0057] In the three-dimensional (3D) Fermi surface, the presence of a neck structure along the (111) direction predicts a concave Fermi surface near point K, as shown in Figure 2(b). The central (internal ring) Fermi surface is an electron orbital (scaled by eH / hc) with even higher potential energy and lower Fermi velocity than the outermost Fermi surface, and the carriers of this orbital are electrons. On the other hand, the outermost concave Fermi surface has negative curvature, so hole carriers are generated. This is because conduction carriers that previously moved along the convex and concave Fermi surfaces are YBa2Cu3O 7-x , La 2-x Sr x CuO4, FeSe, Ba(Fe 1-x Co xThis is because, as observed in quasi-two-dimensional (2D) systems such as 2As2, they contribute to different polarities based on the geometric analysis of the Fermi surface. As shown in Figure 3, it becomes somewhat clearer in periodic domain systems that the two-dimensional Fermi surface (2D FS) is composed of electron pockets located at the center of the domain (blue circle) and hole pockets located at the edges of the domain (red circle).

[0058] To experimentally confirm the Fermi surface reconstruction predicted by quantum constraints, the electronic structure of a two-dimensional (2D) single-crystal copper thin film (SCCF) with a thickness of 80 nm, thin enough to reach the two-dimensional (2D) limit at low temperatures, was directly measured using angle-resolved photoemission spectroscopy (ARPES). As predicted, the Fermi surface topology (Figure 4(a)) taken for the kz=0 plane (Figure 4(a)), which is in clear contrast to the well-known three-dimensional (3D) copper Fermi surface topology (Figure 2(a)), clearly shows two types. The Fermi surface (FS), the large hexagonal Fermi surface (FS) located at the center of the region, and the triangular Fermi surfaces (FS) around the edges of the region closely match the Fermi surface (FS) topology obtained by calculation.

[0059] Figure 5 shows the measurement results of how the Hall resistance changes in response to a magnetic field, as measured by Hall measurements. Unlike Figure 1, it exhibits nonlinear behavior rather than a linear one. This nonlinear behavior becomes even more pronounced as the temperature decreases. Furthermore, this nonlinear behavior appears from single-crystal copper thin films with a thickness of 200 nm or less, and is consistently present down to thin films with a thickness of 10 nm. In particular, the nonlinearity is most clearly evident at a thickness of around 40 nm.

[0060] Using a 40 nm single-crystal copper thin film sample, where nonlinearity is most pronounced, we investigated how GB (gas-bearing) affects hole behavior. The results showed that no nonlinear behavior was observed in samples with GB present, and even with a small amount of GB present, the nonlinearity was weakened. Therefore, hole carriers were observed very clearly in a two-dimensional copper thin film where GB had almost completely disappeared.

[0061] More specifically, to measure the nonlinear Hall effect (NHE) in two-dimensional (2D) copper, we directly investigated hole carrier-dominated (HCD) transport. The Fermi surface of copper originates from the s-band, which is similar to that of free electrons, whereas fully filled d-electrons do not contribute to the electron band near the Fermi level. The s-band properties of copper are sufficiently high in conductivity and up to 1.1 × 10⁻⁶. 6 A Fermi rate of m / s is guaranteed, which is shown in Figure 2(a) through color mapping. As shown in Figure 1, bulk single-crystal copper with a thickness of more than 1 μm has n = 9.09 × 10 at a temperature T = 3 K. 22 cm -3 This exhibits the normal Hall effect with a single carrier (electron) density. As shown in Figure 5(a), this means that even a single crystal of three-dimensional (3D) single-crystal copper behaves similarly to a polycrystalline copper thin film (PCCF) at the two-dimensional (2D) limit.

[0062] Although a concave Fermi surface exists in 3D copper, its region is very narrow and does not continue as a pure hole-type orbital in the Brillouin zone system. Therefore, it is difficult to observe hole carriers in bulk copper. However, different behavior is observed in two-dimensional (2D) single-crystal copper thin film (SCCF) samples in the two-dimensional (2D) region. As shown in Figures 5(b) to 5(f), as the thickness of the two-dimensional (2D) single-crystal copper thin film (SCCF) sample decreases to less than 205 nm, the normal Hall effect, which shows a linear response to an external magnetic field, changes to a nonlinear Hall effect (NHE). Here, the nonlinear Hall effect (NHE) represents a deviation from the linear dependence to an external magnetic field, which is what is known as the normal Hall effect. As shown in Figure 5(b), the nonlinearity at low temperatures appears around a thickness of 205 nm, becomes more pronounced at thicknesses of 80 nm (Figure 5(c)) and 40 nm (Figure 5(d)), and is somewhat suppressed in thin samples of 12 nm (Figure 5(e)) and 10 nm (Figure 5(f)), approaching the limit of thin film growth.

[0063] The present invention will be described in detail below by comparing comparative examples manufactured by conventional methods with embodiments of the present invention and by providing experimental examples. The object, features, and advantages of the present invention can be more easily understood through the following embodiments. The present invention is not limited in any way to the embodiments described in this specification and may be embodied in other forms. The embodiments presented in this specification are provided for the purpose of fully conveying the idea of ​​the present invention to those who have ordinary skill in the art to which the present invention belongs. Therefore, the present invention is not limited by the following embodiments.

[0064] Example 1: Fabrication of single-crystal copper thin films using atomic sputtering epitaxial growth (ASE) technology Copper (Cu) thin films were fabricated using atomic sputtering epitaxial growth (ASE) technique to achieve high-quality crystallinity as single crystals without GB (glub) and single crystals with controlled GB density. The ASE system is an improved radio frequency (RF) sputtering system that uses a single-crystal sputtering target, replaces conventional electrical conductors with single-crystal conductors, and employs a mechanical noise reduction (MNR) system. The optimal growth temperature is approximately 170°C, varying by approximately ±10°C depending on the system. To adjust the GB density, thin films with a thickness of 40 nm and GB were intentionally grown at a lower temperature of 100°C, and the number of GBs was adjusted by additional heat treatment. The number of GBs and twin boundaries (TBs) was obtained with very high precision by electron backscatter diffraction (EBSD) mapping using the misorientation line distribution in the rolling direction (RD) mode. Argon (Ar) gas (99.9999%, 6N) was used as the deposition atmosphere. The relationship between deposition time and thin film thickness (or average growth rate) was determined from the average deposition time of a 200 nm thick thin film grown under optimal conditions. The determined average growth rate was approximately 4.3 nm / min, and this average growth rate is sufficiently reliable for thin films with a thickness of 10 nm or more. The initial pressure for radio frequency (RF) sputtering was 2.3 × 10⁻⁶ -3The operating pressure was Pa, and was adjusted by injecting argon gas (99.9999%) down to 0.5 Pa. The RF output was 25 W, and the rotation speed was 30 RPM. The thickness of the thin film was adjusted by the deposition time and confirmed by atomic force microscopy (AFM). The atomic structure of the single-crystal copper thin film was observed using an annular dark-field (ADF) imaging mode of an aberration-corrected scanning transmission electron microscope (STEM) (JEM-ARM200CF, JEOL Ltd.) operating at 200 kV with a probe formation angle of approximately 23°. The angular range of the annular dark-field (ADF) detector was set to 45 mrad to 170 mrad.

[0065] Experimental Example 1: Structural Measurement Electron backscatter diffraction (EBSD) images were acquired using a fully automated SUPRA® 40 VP system (manufactured by Carl Zeiss AG, Oberkochen, Germany) equipped with an EDAX-TSL Hikari EBSD detector (high-speed EBSD detector). EBSD maps were acquired from a hexagonal grid using a spatial step size of 80 nm. The area size of a single mapping was approximately 174.3 μm. 2 The average confidence index (CI) of the Kikuchi pattern acquired during electron backscatter diffraction (EBSD) scanning was generally in the range of 0.80 to 0.90. However, in the case of polycrystalline copper thin films, the average confidence index (CI) of the Kikuchi pattern was approximately equivalent to 0.7. Statistical analysis of misorientation was derived from the electron backscatter diffraction (EBSD) map using TSL OIM-Analysis v7 software from AMETEK Corporation. When the misorientation angle was greater than 1°, the segment between two adjacent measurement points was treated as a GB (Gross Beam). In the misorientation map, boundaries where the misorientation angle is in the range of 0 to 59° are shown as GBs with blue lines, and boundaries where the misorientation angle is 60° are shown with red lines. The latter is related to the twin boundary (TB) corresponding to the (111) plane of the face-centered cubic (FCC) structure.

[0066] Experimental Example 2: Angle-Resolved Photoelectron Spectroscopy (ARPES) Measurement High-resolution angle-resolved photoelectron spectroscopy (ARPES) measurements were performed at beamline 4.0.3 of the Advanced Light Source (ALS), a synchrotron radiation facility in the United States. The copper thin film measured 5 × 10⁻¹⁶. -10 Annealed in an ultra-high vacuum atmosphere under pressures exceeding Torr, 5 × 10 -11 Measurements were taken at 10K under pressures above Torr. The total energy and angular resolution were set to be greater than 20 meV and 0.1°, respectively.

[0067] Experimental Example 3: Hall Measurement and Sample Preparation Hole bar devices in copper thin films on sapphire substrates were fabricated by electron beam lithography and wet etching using an FeCl3 solution. The typical device channel lengths and widths were 200 μm and 20 μm, respectively. Electrical transport of the copper thin film devices was measured using a cryogen-free superconducting magnet system, "Teslatron PT" (Oxford Instruments NanoScience), in the temperature range of T=1.5K to 300K. A magnetic field (up to 12 Tesla) was applied perpendicular to the planar surface. A direct current (DC) was applied to the device using a Keithley 4200 or Keithley 6221 current source, and the longitudinal (for resistivity and magnetoresistivity) and transverse (for Hole) voltage differences were simultaneously measured using multiple Keithley 2182A voltmeters. The applied current was approximately a few mA.

[0068] Experimental Example 4: Comparison of Polycrystalline and Single-Crystal Samples To compare polycrystalline and single-crystal samples, we prepared polycrystalline thin films with a high concentration of GB and single-crystal thin films with different concentrations of GB.

[0069] The first column shows the results of electron backscatter diffraction (EBSD) measurements performed on a 40 nm thick thin film. The second column shows the number of misalignment lines, with the number of GBs and twinning boundaries (TBs) shown in a table in the far right column. The third column shows the Hall effect measurement results for each sample. Also, (a) shows the GB concentration of 10 2 / μm 2 The above are experimental results for polycrystalline thin films, with (b) to (e) being formed by heat treatment at varying temperatures, respectively. 1 / μm 2 (b), 10 0 / μm 2 (c), 10 -1 / μm 2 This is a single-crystal thin film grown by atomic sputtering epitaxial growth (ASE) with adjusted concentrations of (d) and 0(e).

[0070] Compared to the polycrystalline sample, samples (b) to (d), in which GB was significantly reduced, were perfectly aligned in the (111) direction out of plane, but some GB (blue lines in the second column) still existed in the in-plane direction. The strongest nonlinear behavior was observed in sample (e), in which GB had completely disappeared. The red lines in the second column indicate twinning boundaries (TBs), and since the two adjacent crystal orientations satisfy symmetry, they do not have a clear effect on electron motion.

[0071] By addressing the above-mentioned problems, the present invention solves the defects inherent in ordinary copper and, by lengthening the mean free path of electrons, can change the structure of the Fermi surface where existing electrons reside, thereby altering the shape of the electron orbitals.

[0072] Furthermore, the present invention makes it possible to manufacture copper thin films that can achieve n-type and p-type properties using only copper by changing the shape of the electron orbitals of copper.

[0073] Thus, it can be understood that the technical configuration of the present invention described above can be implemented in other specific forms by a person skilled in the art in which the present invention belongs, without changing the technical idea or essential features of the present invention.

[0074] Therefore, the embodiments described above should be understood to be illustrative and not limiting in all respects, and the scope of the present invention is expressed by the appended claims rather than by the detailed description above, and the meaning and scope of the claims, as well as any modifications or alterations derived therefrom, are included in the scope of the present invention.

Claims

1. It contains a single-crystal copper thin film with a thickness of 200 nm or less. The aforementioned single-crystal copper thin film has suppressed grain boundaries (GB). A single-crystal copper thin film characterized by suppressed grain boundaries, including the nonlinear Hall effect and hole carrier-dominant transport phenomena in a two-dimensional single-crystal thin film.

2. The aforementioned single-crystal copper thin film is Hall resistance exhibits nonlinear behavior in response to a magnetic field. A single-crystal copper thin film in which grain boundaries are suppressed, as described in claim 1, comprising a nonlinear Hall effect and a hole carrier-dominant transport phenomenon.

3. The aforementioned single-crystal copper thin film is Copper is grown on a sapphire substrate by atomic sputtering epitaxial growth (ASE). A single-crystal copper thin film in which grain boundaries are suppressed, as described in claim 1, comprising a nonlinear Hall effect and a hole carrier-dominant transport phenomenon.

4. It includes a single-crystal copper thin film with a thickness of 200 nm or less, and the single-crystal copper thin film has suppressed grain boundaries (GB). The electrical characteristics have changed to p-type. A single-crystal copper thin-film semiconductor characterized by the following features.

5. The aforementioned single-crystal copper thin film is Hall resistance exhibits nonlinear behavior in response to a magnetic field. The single-crystal copper thin-film semiconductor according to claim 4.

6. The aforementioned single-crystal copper thin film is Copper is grown on a sapphire substrate by atomic sputtering epitaxial growth (ASE). The single-crystal copper thin-film semiconductor according to claim 4.

7. It was manufactured by growing a thin copper film by high-frequency (RF) sputtering under temperature conditions of 160°C to 180°C. A method for producing a single-crystal copper thin film in which grain boundaries are suppressed, including the nonlinear Hall effect and hole carrier-dominant transport phenomena.

8. The initial pressure for the aforementioned high-frequency (RF) sputtering is 2.0 × 10⁻⁶ －３ Pa ~ 2.5 × 10 －３ Pa A method for producing a single-crystal copper thin film in which grain boundaries are suppressed, as described in claim 7, including the nonlinear Hall effect and hole carrier-dominant transport phenomena.

9. The aforementioned radio frequency (RF) sputtering is performed in an argon (Ar) gas atmosphere. A method for producing a single-crystal copper thin film in which grain boundaries are suppressed, as described in claim 7, including the nonlinear Hall effect and hole carrier-dominant transport phenomena.

10. The aforementioned radio frequency (RF) sputtering is performed by injecting argon (Ar) gas to 0.3 Pa to 0.7 Pa and adjusting the pressure. A method for producing a single-crystal copper thin film in which grain boundaries are suppressed, as described in claim 7, including the nonlinear Hall effect and hole carrier-dominant transport phenomena.

11. The high-frequency (RF) output of the aforementioned high-frequency (RF) sputtering is 23W to 27W. A method for producing a single-crystal copper thin film in which grain boundaries are suppressed, as described in claim 7, including the nonlinear Hall effect and hole carrier-dominant transport phenomena.

12. The rotational speed of the aforementioned high-frequency (RF) sputtering is 25 RPM to 35 RPM. A method for producing a single-crystal copper thin film in which grain boundaries are suppressed, as described in claim 7, including the nonlinear Hall effect and hole carrier-dominant transport phenomena.

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