Single-crystal diamond substrate with twinning defects removed and method for manufacturing the same

Abstract

The present invention relates to a single-crystal diamond substrate from which twinning defects have been removed and a method for manufacturing the same, and more particularly to a single-crystal diamond substrate from which twinning defects have been removed and a method for manufacturing the same, wherein defects in the substrate are controlled by arranging a buffer layer including an Ir metal layer on the upper surface of a substrate layer including an R-face sapphire substrate, and the single-crystal diamond layer includes a single-crystal diamond layer oriented in the (111) direction.

Description

Technical Field

[0001] The present invention relates to a single-crystal diamond substrate with twin defects removed and a manufacturing method thereof. More specifically, by disposing a buffer layer containing an Ir metal layer on the upper surface of a base material layer including an R-plane sapphire substrate, the defects of the substrate are controlled, and a single-crystal diamond substrate including a single-crystal diamond layer oriented in the (111) direction and a manufacturing method thereof are provided. The present invention relates to a single-crystal diamond substrate with twin defects removed and a manufacturing method thereof.

Background Art

[0002] Recently, a technique for manufacturing a semiconductor device using a single-crystal diamond as a substrate material has been disclosed. A single-crystal diamond substrate is a substrate material for manufacturing a semiconductor device having an ultra-wide bandgap (UWBG). A semiconductor device using a single-crystal diamond substrate has improved energy efficiency and can achieve miniaturization and weight reduction of the semiconductor device, and can manufacture next-generation power devices such as electric vehicles, high-frequency communications, and quantum sensors. Therefore, a technique for manufacturing a high-quality single-crystal diamond substrate is required.

[0003] A diamond semiconductor device substrate oriented in the (111) direction has characteristics of better doping efficiency and quantum characteristics than a substrate oriented in the (001) direction, and is suitable for manufacturing high-performance electronic devices and quantum sensors. However, when the substrate is formed, there is a problem that defects in the substrate are likely to occur.

[0004] That is, there is a need for a technique for forming a single-crystal diamond substrate having a UWBG and oriented in the (111) direction as a substrate for next-generation semiconductor devices, and a single-crystal diamond substrate with controlled substrate defects and a manufacturing method thereof.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to provide a single-crystal diamond substrate and a method for manufacturing the same, in which defects in the substrate are controlled by arranging a buffer layer including an Ir metal layer on the upper surface of a substrate layer including an R-face sapphire substrate, and a single-crystal diamond substrate including a single-crystal diamond layer oriented in the (111) direction, and a method for manufacturing the same, thereby providing a single-crystal diamond substrate and a method for manufacturing the same in which twinning defects are removed. [Means for solving the problem]

[0006] To solve the aforementioned problems, one embodiment of the present invention provides a single-crystal diamond substrate in which defects in the substrate are controlled, comprising a base layer, a buffer layer formed on the base layer, and a single-crystal diamond layer formed on the buffer layer, wherein the base layer comprises a sapphire substrate, the sapphire substrate has an R-plane oriented in a predetermined direction, and the buffer layer comprises an Ir metal layer.

[0007] The single-crystal diamond substrate has three peaks spaced 120 degrees apart on the X-ray diffraction pole figure.

[0008] The single-crystal diamond substrate controls twinning defects that occur during the formation of the single-crystal diamond layer.

[0009] The single-crystal diamond substrate further includes a preliminary diamond layer formed on the buffer layer, the single-crystal diamond layer being formed on the preliminary diamond layer, and the preliminary diamond layer having a thickness thinner than the thickness of the single-crystal diamond layer.

[0010] The single-crystal diamond substrate has a shape in which the base layer, buffer layer, and single-crystal diamond layer are formed in a continuous manner, and then the single-crystal diamond layer is separated from the base layer.

[0011] The buffer layer includes an Ir metal layer oriented in the (111) direction.

[0012] The buffer layer has a thickness of 20 nm to 1 μm.

[0013] The single-crystal diamond layer is grown oriented in a plane direction corresponding to the plane direction of the buffer layer, and defects in the single-crystal diamond substrate are controlled by the buffer layer and the single-crystal diamond layer, which are oriented in plane directions corresponding to each other.

[0014] The single-crystal diamond layer includes a single-crystal diamond layer oriented in the (111) direction.

[0015] To solve the aforementioned problems, one embodiment of the present invention provides a method for manufacturing a single-crystal diamond substrate in which defects in the substrate are controlled, comprising: a substrate layer preparation step of preparing a substrate layer; a buffer layer formation step of forming a buffer layer on the substrate layer; and a single-crystal diamond layer formation step of forming a single-crystal diamond layer on the buffer layer, wherein the substrate layer includes a sapphire substrate, the sapphire substrate has an R-plane oriented in a predetermined direction, and the buffer layer includes an Ir metal layer.

[0016] The single-crystal diamond substrate has three peaks spaced 120 degrees apart on the X-ray diffraction pole figure.

[0017] The single-crystal diamond substrate controls twinning defects that occur during the formation of the single-crystal diamond layer.

[0018] To solve the aforementioned problems, one embodiment of the present invention provides a method for manufacturing a single-crystal diamond substrate in which defects in the substrate are controlled, comprising: a substrate layer preparation step of preparing a substrate layer; a buffer layer formation step of forming a buffer layer on the substrate layer; a preliminary diamond layer formation step of forming a preliminary diamond layer on the buffer layer; and a single-crystal diamond layer formation step of forming a single-crystal diamond layer on the preliminary diamond layer, wherein the substrate layer includes a sapphire substrate, the sapphire substrate has an R-plane oriented in a predetermined direction, and the buffer layer includes an Ir metal layer.

[0019] The single-crystal diamond substrate has three peaks spaced 120 degrees apart on the X-ray diffraction pole figure.

[0020] The single-crystal diamond substrate controls twinning defects that occur during the formation of the single-crystal diamond layer. [Effects of the Invention]

[0021] According to the present invention, by placing a buffer layer containing an Ir metal layer on the upper surface of an R-face sapphire substrate and forming a single-crystal diamond layer on the upper surface of the buffer layer, defects in the (111) oriented single-crystal diamond substrate can be controlled and quality can be improved.

[0022] Furthermore, according to the present invention, by forming an Ir metal layer on the upper surface of the R-shaped sapphire substrate, the effect of controlling defects in the Ir metal layer can be obtained.

[0023] Furthermore, according to the present invention, by growing a single-crystal diamond layer on the upper surface of a buffer layer in which defects in the substrate are controlled, the effect of controlling defects in the single-crystal diamond layer can be obtained.

[0024] Further, according to the present invention, the upper surfaces of the buffer layer and the single crystal diamond layer are each oriented in the (111) direction, and the shapes of the atoms arranged on the upper surfaces correspond to each other, thereby minimizing the residual stress of the single crystal diamond layer due to the difference in lattice constant and thermal expansion coefficient between the single crystal diamond layer and the base material layer, and improving the durability of the single crystal diamond substrate.

[0025] Further, according to the present invention, by forming a preliminary diamond layer serving as a seed of the diamond layer on the upper surface of the buffer layer, the yield of the single crystal diamond layer can be increased.

[0026] Furthermore, according to the present invention, the single crystal diamond substrate can easily provide the single crystal diamond layer by separating the single crystal diamond layer from the base material layer.

Brief Description of the Drawings

[0027] [Figure 1] FIG. 1 is a schematic view of a single crystal diamond substrate according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing matters related to the lattice structure of a sapphire substrate according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing matters related to the lattice structure of iridium (Ir) and diamond according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing matters related to the X-ray diffraction pattern of a base material layer and a buffer layer according to an embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing matters related to the X-ray diffraction pole figure according to an embodiment of the present invention. [Figure 6] FIG. 6 is a diagram schematically showing matters related to known twin defects. [Figure 7] FIG. 7 is a diagram schematically showing a method for manufacturing a single crystal diamond substrate according to an embodiment of the present invention. [Figure 8]Figure 8 is a schematic diagram showing an embodiment of a method for manufacturing a single-crystal diamond substrate according to one embodiment of the present invention. [Figure 9] Figure 9 is a schematic diagram illustrating a method for manufacturing a single-crystal diamond substrate according to another embodiment of the present invention. [Figure 10] Figure 10 is a schematic diagram illustrating an embodiment of a method for manufacturing a single-crystal diamond substrate according to another embodiment of the present invention. [Modes for carrying out the invention]

[0028] Various embodiments and / or modes will be described below with reference to the drawings. In the following description, numerous specific details are disclosed for illustrative purposes to aid in the general understanding of one or more modes. However, it will be recognized by those ordinary skill in the art of the present invention that these modes can also be carried out without such specific details. The following description and accompanying drawings detail specific exemplary modes of one or more modes. However, these modes are illustrative, and some of the various methods of the principles of various modes are available, and the description is intended to include all such modes and their equivalents.

[0029] Furthermore, various aspects and characteristics are presented by systems that include numerous devices, components, and / or modules. It should be understood and recognized that various systems may include further devices, components, and / or modules, and may also not include all of the devices, components, and modules discussed in relation to the drawings.

[0030] The terms "embodiments," "examples," "modes," and "exemplifications" used herein do not necessarily mean that any mode or design described is superior to or has advantages over other modes or designs.

[0031] Furthermore, the terms “includes” and / or “includes” should be understood to mean that the feature and / or component in question is present, but not that one or more other features, components, and / or groups thereof are excluded from the existence or addition of such other features, components, and / or groups thereof.

[0032] Furthermore, terms including ordinal numbers, such as "first," "second," etc., are used to describe various components, but the components are not limited by such terms. The terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may be referred to as the first component. The terms "and" and / or include a combination of multiple related items, or any of the multiple related items.

[0033] Furthermore, in embodiments of the present invention, unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those with ordinary skill in the art to which the present invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as ideally or excessively formal unless explicitly defined in embodiments of the present invention.

[0034] Single-crystal diamond substrates 1 are attracting attention as materials for next-generation semiconductor devices. In particular, single-crystal diamond substrates 1 oriented in the (111) direction have high thermal conductivity and low defect density, making them essential for fabricating high-power and high-performance electronic devices. Preferably, in order to fabricate single-crystal diamond substrates 1 with a large diameter, it is desirable to form the single-crystal diamond substrates 1 by heterogeneous (different species) growth.

[0035] However, the single-crystal diamond substrate 1 oriented in the (111) direction has a small lattice constant, making it difficult to find a suitable substrate layer 100. In particular, the single-crystal diamond substrate 1 oriented in the (111) direction formed by the heterogeneous growth method has the problem of being prone to defects.

[0036] To solve this problem, the present invention attempts to hetero-grow a single-crystal diamond layer 300 on the upper surface of an R-plane sapphire substrate using an Ir (iridium) metal layer oriented in the (111) direction.

[0037] More specifically, in the present invention, a single-crystal diamond substrate 1 can be formed by forming an Ir metal layer on the upper surface of a sapphire substrate having an R-plane (1-102) surface, and then hetero-growing a single-crystal diamond layer 300 on the upper surface thereof.

[0038] Here, it is preferable that the Ir metal layer be oriented in the (111) direction, thereby enabling the single-crystal diamond layer 300 to be oriented in the (111) direction. The (111) direction corresponds to the direction of the crystal plane as indicated by the Miller indices of the crystal planes, where the Miller indices of the crystal planes are expressed as the smallest integer ratio of the reciprocal of the value obtained by dividing the length of the three-dimensional coordinate axis by the unit length of that axis.

[0039] As a result, the single-crystal diamond layer 300 has controlled defects, and is free from or has very few twinning defects, which are a type of defect in the substrate.

[0040] In other words, the present invention provides a high-quality single-crystal diamond substrate 1 by arranging a buffer layer 200 containing an Ir metal layer on the upper surface of a substrate layer 100 containing an R-face sapphire substrate, and forming a single-crystal diamond layer 300 on the upper surface of the buffer layer 200, thereby oriented in the (111) direction, controlling defects in the substrate, and providing a high-quality single-crystal diamond substrate 1.

[0041] The following describes in detail a single-crystal diamond substrate 1 according to one embodiment of the present invention.

[0042] Figure 1 is a schematic diagram of a single-crystal diamond substrate 1 according to one embodiment of the present invention, Figure 2 shows the lattice structure of a sapphire substrate according to one embodiment of the present invention, and Figure 3 shows the lattice structures of iridium (Ir) and diamond according to one embodiment of the present invention.

[0043] As shown in Figure 1, a single-crystal diamond substrate 1 with controlled substrate defects according to one embodiment of the present invention includes a base layer 100, a buffer layer 200 formed on the base layer 100, and a single-crystal diamond layer 1 formed on the buffer layer 200. Here, the base layer 100 includes a sapphire substrate, the sapphire substrate has an R-plane oriented in a predetermined direction, and the buffer layer 200 includes an Ir metal layer.

[0044] The aforementioned substrate layer 100 is a substrate for growing a single-crystal diamond layer 300, and is composed of different components from the single-crystal diamond layer 300. In this invention, a heterogeneous growth method utilizing dissimilar substrates is used, which is suitable for producing large diameters of 2 inches or more, which are used as substrates for semiconductor devices, with high purity.

[0045] Existing heterogeneous growth methods have the problem of generating numerous defects in the substrate when forming single-crystal diamond layers oriented in the (111) direction.

[0046] To address this, the present invention proposes an R-plane sapphire substrate as the base layer 100. In one embodiment of the present invention, the R-plane sapphire substrate corresponds to a sapphire substrate oriented such that its upper surface has a (1-102) direction. As shown in Figure 2, the sapphire substrate has an hcp structure (hexagonal close-packed structure). Due to this structure, the sapphire substrate exhibits no phase change from cryogenic to ultra-high temperatures, is stable with respect to temperature, and has excellent mechanical properties, making it suitable as a substrate for heterogeneous growth.

[0047] More specifically, as shown in Figure 2(a), the R-plane sapphire substrate corresponds to a sapphire substrate having a crystal plane on its upper surface that is tilted at an angle of 35.5 degrees with respect to the c-axis of the sapphire crystal structure. In particular, the R-plane sapphire substrate has higher mechanical strength and thermal stability than sapphire substrates oriented in different plane directions, which means that the R-plane sapphire substrate is more suitable for high-temperature and high-stress fields such as heterogeneous growth. According to one embodiment of the present invention, when an R-plane sapphire substrate is used as the base layer 100 and a buffer layer 200 is placed on top of it, it can be confirmed that defects within the plane of the buffer layer 200 are controlled.

[0048] On the other hand, according to one embodiment of the present invention, by forming an Ir metal layer on the upper surface of an R-face sapphire substrate, the effect of controlling defects in the Ir metal layer can be obtained. This effect can be confirmed by experimental results such as X-ray diffraction analysis and X-ray rotational pole figure analysis, and these experimental results will be shown in the drawings described later.

[0049] On the other hand, a sapphire substrate can have various surfaces in addition to the R-plane mentioned above, for example, it can have a C-plane as shown in Figure 2(b). The C-plane sapphire substrate corresponds to a sapphire substrate having a crystal plane on its upper surface that is tilted at an angle perpendicular to the c-axis of the sapphire crystal structure. According to one embodiment of the present invention, when a buffer layer 200 is placed on a C-plane sapphire substrate as a base layer 100, defects within the buffer layer 200 are not controlled.

[0050] The buffer layer 200 includes an Ir metal layer oriented in the (111) direction. The buffer layer 200 also has a thickness of 20 nm to 1 μm.

[0051] Preferably, the buffer layer 200 is arranged to have a thickness of 100 nm to 700 nm. More preferably, the buffer layer 200 is arranged to have a thickness of 500 nm.

[0052] In one embodiment of the present invention, the buffer layer 200 is formed on the upper surface of the substrate layer using one of the following methods: sputtering, electron beam evaporation (E-beam Evaporation), and chemical vapor deposition (CVD).

[0053] The buffer layer 200 corresponds to a configuration for suppressing defects that occur due to the difference in lattice constants and thermal expansion coefficients between the base layer 100 and the single-crystal diamond layer 300, which are dissimilar substrates, in one embodiment of the present invention.

[0054] Here, it is desirable that the buffer layer has its upper surface oriented in the (111) direction, and that the shape of the atoms arranged on the upper surface of the buffer layer 200 corresponds to the shape of the atoms arranged on the upper surface of the single-crystal diamond layer 300 formed on the upper side.

[0055] More specifically, the buffer layer 200 includes an Ir metal layer having an fcc (face-centered cubic) structure, as shown in Figure 3(a), and the fcc structure has a triangular shape in which atoms are arranged on the crystal plane in the (111) direction. As mentioned above, since the upper surface of the buffer layer 200 is oriented in the (111) direction, it is desirable that the atoms arranged on the upper surface of the buffer layer 200 have a triangular shape.

[0056] On the other hand, the single-crystal diamond layer 300 includes a single-crystal diamond layer having a diamond cubic structure, as shown in Figure 3(b), wherein the shape of atoms arranged on the crystal plane in the (111) direction is triangular.

[0057] In this way, the upper surfaces of the buffer layer 200 and the single-crystal diamond layer 300 are oriented in the (111) direction, and the shapes of the atoms arranged on the upper surfaces correspond to each other. This minimizes the residual stress in the single-crystal diamond layer 300 due to the difference in lattice constants and thermal expansion coefficients between the single-crystal diamond layer 300 and the substrate layer 100, thereby improving the durability of the single-crystal diamond substrate 1.

[0058] The single-crystal diamond layer 300 is formed on the upper surface of the buffer layer 200 and is configured to be usable as a substrate for semiconductor elements and electronic elements.

[0059] Generally, a single-crystal diamond layer 300 can be manufactured by various manufacturing methods such as high-temperature and high-pressure methods, homo-growth methods, and hetero-growth methods. The present invention relates to a hetero-grown single-crystal diamond layer 300, and according to one embodiment of the present invention, the single-crystal diamond layer 300 is formed using one of ALD (atomic layer deposition), CVD, or PVD (physical vapor deposition) equipment, and as the CVD equipment, HF-CVD (hot filament-CVD), MP-CVD (micro plasma-CVD), or RF-CVD (RF plasma-CVD) equipment can be used.

[0060] In one embodiment of the present invention, the single-crystal diamond layer 300 is grown oriented in a plane direction corresponding to the plane direction of the buffer layer 200, and the single-crystal diamond substrate 1 can control defects by the buffer layer 200 and the single-crystal diamond layer 300 oriented in plane directions corresponding to each other.

[0061] As a result, the single-crystal diamond layer 300 includes a single-crystal diamond layer 300 oriented in the (111) direction. Here, defects in the single-crystal diamond layer 300 are controlled by forming a buffer layer 200 on the upper surface of the substrate layer 100.

[0062] In other words, according to one embodiment of the present invention, by growing a single-crystal diamond layer 300 on the upper surface of a defect-controlled buffer layer 200, the effect of controlling defects in the single-crystal diamond layer 300 can be obtained, and by arranging a buffer layer 200 containing an Ir metal layer oriented in the (111) direction, the quality of the (111) oriented single-crystal diamond layer 300 can be improved.

[0063] Figure 4 shows the X-ray diffraction patterns of the substrate layer 100 and buffer layer 200 according to one embodiment of the present invention.

[0064] The base layer 100 is oriented in the (1-102) direction on the R-surface sapphire substrate, and the buffer layer 200 is oriented in the (111) direction.

[0065] In one embodiment of the present invention, the substrate layer 100 and the buffer layer 200 exhibit X-ray diffraction patterns as shown in Figure 4. According to the patterns, the substrate layer has an R-plane sapphire substrate oriented in the (1-102) direction, and the buffer layer 200 also has an Ir metal layer oriented in the (111) direction. Here, the Sapphire(012) peak in Figure 4 corresponds to the aforementioned (1-102) direction.

[0066] Thus, the base layer 100 and the buffer layer 200 are layers made of single crystal.

[0067] Figure 5 shows details regarding X-ray diffraction pole figures according to one embodiment of the present invention, and Figure 6 schematically shows details regarding known twinning defects.

[0068] A single-crystal diamond substrate 1 according to one embodiment of the present invention can have three peaks spaced 120 degrees apart on an X-ray diffraction pole figure.

[0069] The aforementioned X-ray diffraction pole figure is an analytical method that shows the directional distribution of lattice planes within a plane. As shown in Figure 5, the substrate layer 100 and the buffer layer 200 can have three peaks at 120-degree intervals on the X-ray diffraction pole figure. This means that no twinning defects occurred within the respective planes of the substrate layer 100 and the buffer layer 200. In other words, the single-crystal diamond layer 300 according to one embodiment of the present invention has controlled twinning defects.

[0070] More specifically, a twinning defect is a type of defect that frequently occurs when growing a single-crystal diamond layer 300 oriented in the (111) direction, and occurs when the crystal lattice is oriented in different planes within the corresponding plane. As mentioned above, since the buffer layer 200 and the single-crystal diamond layer 300 are oriented in the (111) direction, the shape of the atoms arranged on the upper surface is triangular. At this time, each of the buffer layer 200 and the single-crystal diamond layer 300 shows an X-ray diffraction pole figure as shown in Figure 6(a), and as shown in Figure 6(a), each of the buffer layer 200 and the single-crystal diamond layer 300 has an α of 120 degrees, which is the angle between the peak and the central axis. This means that no twinning defects occurred within the plane of the buffer layer 200 and the single-crystal diamond layer 300.

[0071] On the other hand, as shown in Figure 6(b), when β, which corresponds to the angle between the peak and the central axis, shows an angle of 60 degrees, it means that twinning defects have occurred within the planes of the buffer layer 200 and the single-crystal diamond layer 300. For example, if any one plane within the Ir metal layer plane contained in the buffer layer 200 is rotated 60 degrees clockwise with respect to the central axis, the peaks of the X-ray diffraction pole figure can have the shape shown in Figure 6(b). Here, β has an angle of 60 degrees, and there can be six peaks on the X-ray diffraction pole figure that are spaced 60 degrees apart from each other. On the other hand, the difference in the X-ray diffraction pole figure as described above is due to the relatively high energy required to generate defects in the single-crystal diamond layer 300 formed on the R-plane sapphire substrate.

[0072] In other words, according to one embodiment of the present invention, by growing a single-crystal diamond layer 300 on the upper surface of a buffer layer 200 in which defects of the substrate are controlled, the effect of controlling defects in the single-crystal diamond layer 300 is obtained.

[0073] The following describes in detail a method for manufacturing a single-crystal diamond substrate 1 according to one embodiment of the present invention.

[0074] Figure 7 schematically shows a method for manufacturing a single-crystal diamond substrate 1 according to one embodiment of the present invention, and Figure 8 schematically shows an embodiment in which each step of the method for manufacturing a single-crystal diamond substrate 1 according to one embodiment of the present invention is performed.

[0075] On the other hand, a single-crystal diamond substrate 1 according to one embodiment of the present invention is formed by the following manufacturing method.

[0076] Preferably, the process includes a base layer preparation step (S100) for preparing a base layer 100, a buffer layer formation step (S200) for forming a buffer layer 200 on the base layer 100, and a single crystal diamond layer formation step (S400) for forming a single crystal diamond layer 300 on the buffer layer 200, wherein the base layer 100 includes a sapphire substrate, the sapphire substrate has an R-plane oriented in a predetermined direction, and the buffer layer 200 includes an Ir metal layer.

[0077] With this configuration, the single-crystal diamond substrate 1 has three peaks spaced 120 degrees apart on the X-ray diffraction pole figure, and twinning defects that occur during the formation of the single-crystal diamond layer 300 can be controlled.

[0078] More specifically, in one embodiment of the present invention, in order to form the single-crystal diamond substrate 1, a buffer layer 200 is formed on the upper surface of the substrate layer 100, as shown in Figures 8(a) and 8(b). Subsequently, a single-crystal diamond layer 300 is formed on the upper surface of the buffer layer 200, as shown in Figure 8(c).

[0079] With this configuration, the buffer layer 200 is oriented in the (111) direction, and substrate defects are controlled. The single-crystal diamond layer 300 is grown on the upper surface of the buffer layer 200, where substrate defects are controlled, thereby achieving the effect of controlling substrate defects. Furthermore, by forming the single-crystal diamond layer 300 on the upper surface of the buffer layer 200, residual stress due to the difference in lattice constant and thermal expansion coefficient between the single-crystal diamond layer 300 and the substrate layer 100 can be minimized, thereby improving the durability of the single-crystal diamond substrate 1.

[0080] On the other hand, a single-crystal diamond substrate 1 manufactured by such a manufacturing method may have a shape in which the base layer 100, buffer layer 200, and single-crystal diamond layer 300 are formed continuously, and then the single-crystal diamond layer 300 is separated from the base layer 100.

[0081] Here, the single-crystal diamond substrate 1 can be separated from either the upper surface of the base material layer 100 or the lower surface of the single-crystal diamond layer 300.

[0082] In other words, the single-crystal diamond substrate 1 according to one embodiment of the present invention has the effect of easily providing the single-crystal diamond layer 300 by separating the single-crystal diamond layer 300 from the base layer 100.

[0083] Figure 9 schematically shows a method for manufacturing a single-crystal diamond substrate 1 according to another embodiment of the present invention, and Figure 10 schematically shows an embodiment of each step of the method for manufacturing a single-crystal diamond substrate 1 according to another embodiment of the present invention.

[0084] On the other hand, the present invention further includes a preliminary diamond layer 400 that assists in the formation process of the single-crystal diamond layer 300. The single-crystal diamond substrate 1 further including the preliminary diamond layer 400 is formed by the following manufacturing method.

[0085] Preferably, the process includes a base layer preparation step (S100) for preparing a base layer 100, a buffer layer formation step (S200) for forming a buffer layer 200 on the base layer 100, a preliminary diamond layer formation step (S400) for forming a preliminary diamond layer 400 on the buffer layer, and a single crystal diamond layer formation step (S300) for forming a single crystal diamond layer 300 on the preliminary diamond layer 400, wherein the base layer 100 includes a sapphire substrate, the sapphire substrate has an R-plane oriented in a predetermined direction, and the buffer layer 200 includes an Ir metal layer.

[0086] With this configuration, the single-crystal diamond substrate 1 can have three peaks spaced 120 degrees apart on the X-ray diffraction pole figure, and twinning defects that occur during the formation of the single-crystal diamond layer 300 can be controlled.

[0087] Furthermore, with this configuration, the single-crystal diamond substrate 1 further includes a preliminary diamond layer 400 formed on the buffer layer 200, the single-crystal diamond layer 300 is formed on the preliminary diamond layer 400, and the preliminary diamond layer 400 has a thickness thinner than the thickness of the single-crystal diamond layer 300.

[0088] More specifically, in order to form the single-crystal diamond substrate 1, a buffer layer 200 is formed on the upper surface of the base layer 100, as shown in Figures 9(a) and 9(b). Subsequently, as shown in Figure 9(c), a preliminary diamond layer 400 is formed on the upper surface of the buffer layer 200, and the preliminary diamond layer 400 acts as a seed for the single-crystal diamond layer 300, thereby facilitating the formation of the single-crystal diamond layer 300.

[0089] In other words, according to one embodiment of the present invention, the yield of the single-crystal diamond layer 300 can be increased by forming a preliminary diamond layer 300 on the upper surface of the buffer layer 200, which serves as a seed for the diamond layer.

[0090] According to one embodiment of the present invention, by placing a buffer layer containing an Ir metal layer on the upper surface of an R-plane sapphire substrate and forming a single-crystal diamond layer on the upper surface of the buffer layer, defects in the (111) oriented single-crystal diamond substrate can be controlled and quality can be improved.

[0091] According to one embodiment of the present invention, by forming an Ir metal layer on the upper surface of an R-shaped sapphire substrate, the effect of controlling defects in the Ir metal layer can be obtained.

[0092] According to one embodiment of the present invention, by growing a single-crystal diamond layer on the upper surface of a buffer layer in which defects in the substrate are controlled, the effect of controlling defects in the single-crystal diamond layer can be obtained.

[0093] According to one embodiment of the present invention, the upper surfaces of the buffer layer and the single-crystal diamond layer are oriented in the (111) direction, and the shapes of the atoms arranged on the upper surfaces correspond to each other. This minimizes the residual stress in the single-crystal diamond layer due to the difference in lattice constant and thermal expansion coefficient between the single-crystal diamond layer and the substrate layer, thereby improving the durability of the single-crystal diamond substrate.

[0094] According to one embodiment of the present invention, the yield of the single-crystal diamond layer 300 can be increased by forming a preliminary diamond layer 300 on the upper surface of the buffer layer 200, which serves as a seed for the diamond layer.

[0095] In one embodiment of the present invention, a single-crystal diamond substrate is provided with the advantage of easily offering the single-crystal diamond layer by separating the single-crystal diamond layer from the base material layer.

[0096] Although the embodiments have been described above with limited embodiments and drawings, various modifications and variations can be made from the above description by a person with ordinary skill in the art. For example, the described technology may be performed in a different order than described, and / or the components of the described system, structure, apparatus, circuit, etc. may be combined in a different manner than described, or replaced or substituted with other components or equivalents, and the appropriate results may be achieved. Therefore, other embodiments, other forms, and equivalents to the claims also fall within the scope of the claims described below.

Claims

1. A single-crystal diamond substrate in which substrate defects are controlled, A base layer and A buffer layer formed on the substrate layer, The buffer layer includes a single-crystal diamond layer formed on the buffer layer, The substrate layer includes a sapphire substrate, The sapphire substrate has an R-shaped surface oriented in a predetermined direction, The buffer layer is characterized by containing an Ir metal layer, forming a single-crystal diamond substrate.

2. The single-crystal diamond substrate according to claim 1, characterized in that the buffer layer has three peaks spaced 120 degrees apart on an X-ray diffraction pole figure.

3. The single-crystal diamond substrate according to claim 1, characterized in that it controls twinning defects that occur during the formation of the single-crystal diamond layer.

4. The single-crystal diamond substrate further includes a preliminary diamond layer formed on the buffer layer, The single-crystal diamond layer is formed on the preliminary diamond layer, The single-crystal diamond substrate according to claim 1, characterized in that the pre-diamond layer has a thickness thinner than the thickness of the single-crystal diamond layer.

5. The single-crystal diamond substrate according to claim 1, characterized in that the single-crystal diamond substrate has a shape in which the base layer, buffer layer, and single-crystal diamond layer are formed in a continuous manner, and then the single-crystal diamond layer is separated from the base layer.

6. The single-crystal diamond substrate according to claim 1, characterized in that the buffer layer includes an Ir metal layer oriented in the (111) direction.

7. The buffer layer is a single-crystal diamond substrate according to claim 1, characterized in that it has a thickness of 20 nm to 1 μm and has controlled twinning defects.

8. The single-crystal diamond layer is grown oriented in a plane direction corresponding to the plane direction of the buffer layer. The single-crystal diamond substrate according to claim 1, characterized in that defects in the substrate are controlled by the buffer layer and the single-crystal diamond layer oriented in corresponding planar directions.

9. The single-crystal diamond substrate according to claim 6, characterized in that the single-crystal diamond layer includes a single-crystal diamond layer oriented in the (111) direction.

10. A method for manufacturing a single-crystal diamond substrate in which substrate defects are controlled, A base layer preparation step to prepare the base layer, A buffer layer formation step in which a buffer layer is formed on the substrate layer, The step includes forming a single-crystal diamond layer on the buffer layer, The substrate layer includes a sapphire substrate, The sapphire substrate has an R-shaped surface oriented in a predetermined direction, A method for manufacturing a single-crystal diamond substrate, characterized in that the buffer layer includes an Ir metal layer.

11. The method for manufacturing a single-crystal diamond substrate according to claim 10, characterized in that the buffer layer has three peaks spaced 120 degrees apart on an X-ray diffraction pole figure.

12. The method for manufacturing a single-crystal diamond substrate according to claim 10, characterized in that the single-crystal diamond substrate controls twinning defects that occur during the formation of the single-crystal diamond layer.

13. A method for manufacturing a single-crystal diamond substrate in which substrate defects are controlled, A base layer preparation step to prepare the base layer, A buffer layer formation step in which a buffer layer is formed on the substrate layer, The steps include forming a preliminary diamond layer on the buffer layer, The step includes forming a single-crystal diamond layer on the aforementioned pre-diamond layer, The substrate layer includes a sapphire substrate, The sapphire substrate has an R-shaped surface oriented in a predetermined direction, A method for manufacturing a single-crystal diamond substrate, characterized in that the buffer layer includes an Ir metal layer.

14. The method for manufacturing a single-crystal diamond substrate according to claim 13, characterized in that the buffer layer has three peaks spaced 120 degrees apart on an X-ray diffraction pole figure.

15. The method for manufacturing a single-crystal diamond substrate according to claim 13, characterized in that the single-crystal diamond substrate controls twinning defects that occur during the formation of the single-crystal diamond layer.

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