High mobility substrate having delta doped layer and method for manufacturing high mobility substrate

Abstract

The present invention relates to a high mobility substrate comprising: a semiconductor substrate; the band gap on the semiconductor substrate is larger than that of the first delta doping layer of the semiconductor substrate; a thin film of the same material as the semiconductor substrate on the first delta doped layer; the band gap on the thin film is larger than that of the second delta doped layer of the semiconductor substrate, and the structure of the high mobility substrate is that the thin film is clamped between the first delta doped layer and the second delta doped layer. As a result, it is possible to provide a relatively practical high-mobility substrate and a method for manufacturing a high-mobility substrate, which can achieve high mobility and can be manufactured uniformly over the entire surface of a large-area substrate.

Description

Technical Field

[0001] This invention relates to a high mobility substrate having a δ-doped layer and a method for manufacturing the high mobility substrate. Background Technology

[0002] As the next-generation channel material for the current mainstream FinFET (Fin Field Effect Transistor) and some practically applied GAAFET (Gate All Around Field Effect Transistor), two-dimensional materials such as MoS2 are being actively researched. This is a technology that seeks to improve performance by using high-mobility materials as channel materials, as the performance gains brought about by miniaturization have reached their limit.

[0003] However, among the proposed two-dimensional materials, such as MoS2, graphene, and BN, significant differences in their properties have been confirmed, but it is still difficult to obtain films with large diameters. Non-Patent Literature 1 illustrates an example of BN, but in that case, the film was deposited from the center to about half of a silicon substrate with a diameter of 100 mm.

[0004] Furthermore, given the material's properties (stable existence in a two-dimensional thin film), it is easy to imagine that it is difficult to attach or fix to a substrate, making it more difficult than film formation. In devices that have already proven to work, two-dimensional materials are being fixed using source / drain electrode materials.

[0005] On the other hand, focusing on silicon materials, by setting up a structure that uses a silicon oxide film to sandwich a thin silicon layer of about 2-3 nm, the mobility is improved. This was known in the early days of SOI (Silicon on Insulator), and it can achieve a mobility comparable to that of two-dimensional materials such as MoS2 (Non-Patent Literature 2 and 3).

[0006] As mentioned above, if a structure is constructed by covering (sandwiching) silicon with an insulating film, the mobility is improved, achieving mobility comparable to that of two-dimensional materials. However, this also presents the problem of difficulty in forming a uniform structure across the entire surface of the wafer, for example, the entire surface of a substrate with a diameter of 300 mm. In the conventional approach, the wafer with the oxide film formed is first sandwiched between the silicon and the silicon substrate with implanted hydrogen. ＋ The substrate is bonded and peeled off, thereby transferring the silicon layer onto the oxide film and further forming the oxide film. However, it is difficult to control the uniformity of the entire 300mm diameter surface with a thickness of 2~3nm, and there is a problem of in-plane uniformity of the oxide film (the in-plane uniformity of the oxidation furnace must be suppressed to below 0.1nm within a diameter of 300mm).

[0007] Existing technical documents

[0008] Non-patent literature

[0009] Non-patent literature 1: ISSCC2021.1.1, Mark Liu, “Unleashing the Future of Innovation”

[0010] Non-patent literature 2: ISSCC2023.27.3, D. Verrreck et al., “The promise of 2-D materials for scaled digital and analog applications”

[0011] Non-patent document 3: Sumida, "Suppression of surface irregularity and anisotropy of electron valleys and use of polar thin film nMOSFETs" "Optimum Design of Surface Orientation of Materials", Proceedings of the 70th Spring Academic Lectures of the Society for Applied Physics in 2023, 16p-A403-2. Summary of the Invention

[0012] (a) Technical problems to be solved

[0013] As mentioned above, even though it is known that high mobility can be achieved by covering (clamping) silicon with an oxide film after thinning, it is still difficult to fabricate it uniformly on the entire surface of the substrate, making it impractical.

[0014] The present invention was made in view of the problems of the prior art mentioned above, and its purpose is to provide a high mobility substrate and a method for manufacturing a high mobility substrate. The high mobility substrate can achieve high mobility and can be uniformly fabricated on the entire surface of a large-area substrate, and is a practical high mobility substrate.

[0015] (II) Technical Solution

[0016] To solve the above-mentioned technical problems, the high mobility substrate of the present invention comprises: a semiconductor substrate; a first δ-doped layer on the semiconductor substrate with a band gap larger than that of the semiconductor substrate; a thin film on the first δ-doped layer made of the same material as the semiconductor substrate; a second δ-doped layer on the thin film with a band gap larger than that of the semiconductor substrate; and the high mobility substrate is structured such that the thin film is sandwiched between the first δ-doped layer and the second δ-doped layer.

[0017] If it is such a high mobility substrate, since the band gap of the first δ-doped layer and the second δ-doped layer is larger than that of the thin film, a band bending (also known as band bending) will occur at the bonding interface between the thin film and each δ-doped layer, which is similar to the band bending that can be observed when bonding a semiconductor with an insulator with a band gap larger than that of the semiconductor. This forms a trench with a low potential, thereby improving the mobility.

[0018] Furthermore, if a δ-doped layer is used, the interface roughness (coarseness) will not increase, thus preventing the mobility from decreasing due to interface scattering and maintaining a high mobility.

[0019] Furthermore, delta-doped layers can be easily doped onto semiconductor substrates and thin films, even on large-area substrates, especially large-diameter substrates, and can be fabricated uniformly across the entire surface. Here, delta doping is defined as doping where the thickness of the doped layer is thin (e.g., less than 3 nm).

[0020] Furthermore, it is preferred that the first δ-doped layer and the second δ-doped layer are oxygen δ-doped layers, the semiconductor substrate and the thin film are silicon, and the thickness of the thin film is more than 2 nm and less than 3 nm.

[0021] If it is such an oxygen δ-doped layer, a silicon oxide film SiO2 will be formed on the silicon substrate and the silicon thin film as an insulating film, thereby forming a structure in which a thin silicon layer of 2nm or more and less than 3nm is sandwiched by the silicon oxide film. Therefore, the mobility will be significantly improved, thus achieving a mobility comparable to that of two-dimensional materials such as MoS2.

[0022] Furthermore, the method for manufacturing the high mobility substrate of the present invention is as follows: on a semiconductor substrate, a first δ-doped layer with a band gap larger than that of the semiconductor substrate is formed; a thin film of the same material as that of the semiconductor substrate is formed on the first δ-doped layer; a second δ-doped layer with a band gap larger than that of the semiconductor substrate is formed on the thin film; and the thin film is sandwiched between the first δ-doped layer and the second δ-doped layer.

[0023] If such a high mobility substrate is manufactured, the band gaps of the first δ-doped layer and the second δ-doped layer are larger than those of the thin film. Therefore, at the bonding interface between the thin film and each δ-doped layer, band bending (also known as band bending) will occur, which is similar to that observed when bonding a semiconductor with an insulator whose band gap is larger than that of the semiconductor. This forms a trench with a low potential, thereby improving the mobility.

[0024] Furthermore, if a δ-doped layer is used, the interface roughness (coarseness) will not increase, thus preventing the mobility from decreasing due to interface scattering and maintaining a high mobility.

[0025] Furthermore, δ-doped layers can be easily doped on semiconductor substrates and thin films, and even large-area substrates, especially large-diameter substrates, can be fabricated uniformly over the entire surface.

[0026] Furthermore, it is preferable to set the first δ-doped layer and the second δ-doped layer as oxygen δ-doped layers, set the semiconductor substrate and the thin film as silicon, and set the thickness of the thin film to be more than 2 nm and less than 3 nm.

[0027] If such an oxygen δ-doped layer is formed, a silicon oxide film SiO2 is formed on the silicon substrate and the silicon thin film as an insulating film, thereby forming a structure in which a thin silicon layer of 2nm or more and less than 3nm is sandwiched by the silicon oxide film. Therefore, the mobility will be significantly improved, thereby achieving a mobility comparable to that of two-dimensional materials such as MoS2.

[0028] Furthermore, it is preferable that, when forming the thin film, the thickness is predetermined to be thinner due to oxidation, and the thin film is oxidized to form the second δ-doped layer.

[0029] If this method is adopted, it is possible to prevent the film from becoming too thin and to reliably form the desired thickness.

[0030] Furthermore, it is preferable to repeatedly perform multiple operations on the first δ-doped layer to form silicon with a thickness of 1 nm or more and 3 nm or less, and then further form an oxygen δ-doped layer thereon, and then form the silicon film with a thickness of 2 nm or more and 3 nm or less thereon.

[0031] If this method is adopted, high mobility substrates can be reliably manufactured even with a stacked structure.

[0032] (III) Beneficial Effects

[0033] If the high mobility substrate and the manufacturing method of the high mobility substrate of the present invention are applicable, then high mobility can be achieved and the substrate can be uniformly fabricated on the entire surface of a large-area substrate, especially a large-diameter substrate, which is more practical.

[0034] Furthermore, if such a thin film layer simulating two-dimensional material is used, it is possible to form a high-migration channel material on the entire surface of a large-area substrate, especially a large-diameter substrate.

[0035] Furthermore, it is inexpensive because it can be implemented using conventional semiconductor materials such as silicon without using expensive two-dimensional materials such as MoS2. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a high mobility substrate according to a first embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram of a high mobility substrate according to a second embodiment of the present invention.

[0038] Figure 3 This is a schematic diagram of a high mobility substrate according to a third embodiment of the present invention. Detailed Implementation

[0039] The present invention will be described in detail below, but the present invention is not limited thereto.

[0040] The inventors of this application conducted repeated and in-depth research to solve the aforementioned technical problems, and as a result, discovered the following, thus completing the present invention, which comprises: a semiconductor substrate; a first δ-doped layer on the semiconductor substrate with a band gap greater than that of the semiconductor substrate; a thin film of the same material as the semiconductor substrate on the first δ-doped layer; a second δ-doped layer on the thin film with a band gap greater than that of the semiconductor substrate; and a structure in which the thin film is sandwiched between the first δ-doped layer and the second δ-doped layer. Specifically, the present invention was completed by discovering the following fact: by combining δ-doping with the stacking and oxidation of thin-film silicon, a structure is formed in which a thin-film silicon with a thickness of 2 nm or more and less than 3 nm is sandwiched between an oxide film (more specifically, a material with a band gap greater than that of silicon, i.e., SiO2) that serves as a δ-doped layer and is an insulator. This allows for the formation of a cheaper and higher-quality substrate without using expensive two-dimensional materials.

[0041] This can be achieved, for example, by δ-doping oxygen atoms on a silicon substrate, further stacking silicon layers thereon to a thickness of more than 2 nm and less than 3 nm to form a thin film silicon, and further δ-doping oxygen atoms.

[0042] Furthermore, it can also be provided by: δ-doping oxygen atoms on a silicon substrate, further stacking silicon on it to a thickness that is expected to thin due to oxidation to form a thin film silicon, and then performing oxidation.

[0043] Furthermore, it can also be provided by: δ-doping oxygen atoms on a silicon substrate, repeatedly stacking silicon layers to a thickness of 1 nm or more and less than 3 nm, with a desired thickness of 1 nm, and further δ-doping oxygen atoms, and then further stacking silicon layers on it to a thickness of 2-3 nm to form a thin film silicon, and further δ-doping oxygen atoms.

[0044] A suitable first embodiment of the present invention will now be described with reference to the accompanying drawings.

[0045] First, refer to Figure 1 The structure of the high mobility substrate 1 will be described.

[0046] like Figure 1As shown, the high mobility substrate 1 of this embodiment has: a semiconductor substrate (support substrate) 2; a first δ-doped layer (first oxide film layer) 3-1 on the semiconductor substrate 2 with a band gap greater than that of the semiconductor substrate 2; a thin film (silicon) 4 on the first δ-doped layer 3-1 with the same material as the semiconductor substrate 2; and a second δ-doped layer (second oxide film layer) 3-2 on the thin film 4 with a band gap greater than that of the semiconductor substrate 2. The structure of the high mobility substrate 1 is that the thin film 4 is sandwiched between the first δ-doped layer 3-1 and the second δ-doped layer 3-2.

[0047] Here, a more preferred embodiment is that the first δ-doped layer 3-1 and the second δ-doped layer 3-2 are oxygen δ-doped layers, each forming an oxide film. Furthermore, the semiconductor substrate 2 and the thin film 4 are silicon, and their thickness is 2 nm or more and 3 nm or less to exhibit high mobility. If the thickness is 2 nm or more, the thin film (silicon) layer 4 can easily become perfectly crystalline, thereby improving mobility. On the other hand, if the thickness is 3 nm or less, it will form characteristics different from typical bulk silicon, potentially improving mobility more effectively. Hereinafter, as a preferred embodiment, the case where the semiconductor substrate 2 is a silicon substrate and the δ-doped layer is an oxide film layer will be described. Additionally, when the δ-doping is oxygen doping, it can be formed by thermal oxidation or natural oxidation.

[0048] If the substrate 1 of this embodiment is a high mobility substrate, the band gaps of the first δ-doped layer 3-1 and the second δ-doped layer 3-2 are larger than those of the thin film 4. Therefore, at the bonding interface between the thin film 4 and each δ-doped layer, band bending (also known as band bending) can be observed when bonding a semiconductor with an insulator with a band gap larger than that of the semiconductor, thereby forming a trench with a low potential and thus improving mobility.

[0049] Furthermore, if a δ-doped layer is used, the interface roughness (coarseness) will not increase, thus preventing the mobility from decreasing due to interface scattering and maintaining a high mobility.

[0050] Furthermore, the delta-doped layer can be easily doped on semiconductor substrates and thin films, and even large-area substrates, especially large-diameter substrates, can be fabricated uniformly over the entire surface.

[0051] If the oxygen δ-doped layer (first δ-doped layer 3-1 and second δ-doped layer 3-2) of this embodiment is used, a silicon oxide film SiO2 as an insulating film will be formed on the silicon substrate (semiconductor substrate 2) and the silicon thin film (thin film 4) to form a structure in which a thin silicon (thin film 4) of 2 nm or more and 3 nm or less is sandwiched by the silicon oxide film. Therefore, the mobility is indeed improved and the mobility can be achieved to the same extent as two-dimensional materials such as MoS2.

[0052] Next, refer to Figure 1The specific manufacturing process of the high mobility substrate 1 in this embodiment will be described. A semiconductor substrate (support substrate) 2 is prepared, but it can be a conventional silicon substrate. When it is a silicon substrate, from the perspective of electron mobility, a (100) orientation is preferred. Considering the balance of hole mobility, a (110) substrate can also be used. The substrate orientation can be selected according to its application.

[0053] Next, a first δ-doped layer (first oxide film layer) 3-1 with a band gap larger than that of oxygen in the semiconductor substrate (support substrate) 2 is formed on the semiconductor substrate (support substrate) 2. If the method of forming the δ-doped layer on the semiconductor substrate 2 is adopted, the δ-doped layer can also be uniformly formed on a large-diameter substrate such as a substrate with a diameter of 300 mm.

[0054] The method for forming the δ-doped layer is not particularly limited. It is anticipated that a thin film (silicon) 4 of the same material as the semiconductor substrate will be further formed on it, and the oxygen concentration can be set to a concentration suitable for growth in single-crystal silicon. In this case, it is preferable to set the oxygen concentration to 1 × 10⁻⁶. 15 atoms / cm 2 about.

[0055] Next, a thin film (silicon) 4 layer, made of the same material as the semiconductor substrate 2, is grown on the first δ-doped layer 3-1. When growing it into a thin film with a thickness of 2 nm or more and less than 3 nm, there are no particular limitations on the growth method. If an apparatus capable of setting low temperature and reduced pressure conditions is used, it can be easily grown.

[0056] Next, a second δ-doped layer (second oxide film layer) 3-2 with a band gap larger than that of oxygen in the semiconductor substrate 2 is formed on the thin film 4. This method is acceptable even if it is the same as the method for forming the first δ-doped layer (first oxide film layer) 3-1.

[0057] Through the above methods, a thin film 4 can be sandwiched between the first δ-doped layer 3-1 and the second δ-doped layer 3-2, thereby enabling the fabrication of... Figure 1 Such a high mobility substrate 1.

[0058] If the high mobility substrate 1 of this embodiment is manufactured by a method, the band gaps of the first δ-doped layer 3-1 and the second δ-doped layer 3-2 are larger than those of the thin film 4. Therefore, at the bonding interface between the thin film 4 and each δ-doped layer, band bending (also known as band bending and bandbending) that can be observed when bonding a semiconductor with an insulator with a band gap larger than that of the semiconductor will be generated, thereby forming a trench with a low potential, which can improve the mobility.

[0059] Furthermore, if a δ-doped layer is used, the interface roughness (coarseness) will not increase, thus preventing the mobility from decreasing due to interface scattering and maintaining a high mobility.

[0060] Furthermore, the delta-doped layer can be easily doped on semiconductor substrates and thin films, and even large-area substrates, especially large-diameter substrates, can be fabricated uniformly over the entire surface.

[0061] If the oxygen δ-doped layer (first δ-doped layer 3-1 and second δ-doped layer 3-2) is set as the oxygen δ-doped layer in this embodiment, a silicon oxide film SiO2 as an insulating film will be formed on the silicon substrate (semiconductor substrate 2) or silicon thin film (thin film 4) to form a structure in which a thin silicon (thin film 4) of 2 nm or more and 3 nm or less is sandwiched by the silicon oxide film. Therefore, the mobility will be significantly improved, thereby achieving a mobility equivalent to that of two-dimensional materials such as MoS2.

[0062] Reference Figure 2 The second implementation plan will be explained.

[0063] The high mobility substrate manufacturing method of this embodiment is to form a second δ-doped layer by oxidizing the thin film to a thickness that is expected to thin due to oxidation during the thin film formation process.

[0064] Figure 2 The diagram shows the state of the thin film (silicon) 5 before oxidation. The thin film (silicon) 5 has: a region 5-1 oxidized to form a second δ-doped layer; and a region 5-2 remaining as a thin film (silicon) without oxidation. Furthermore, in order to ensure that the region 5-2 remaining as a thin film (silicon) without oxidation is 2 nm or more and 3 nm or less, the thin film (silicon) 5 is pre-grown to a thickness greater than 2 nm or more and 3 nm or less. The oxidation method can be a thermal oxidation method for the thin film 5.

[0065] Regarding the estimated thinning level and the setting of a thicker thickness, if silicon is oxidized to form an oxide film, then about half of the oxide film is silicon (for example, if it is a 100 Å oxide film, then 44 Å of silicon is used). This ratio can be determined, but it can be more accurately confirmed through preliminary experiments, etc.

[0066] If this method is adopted, it is possible to prevent the unoxidized portion 5-2 remaining in the thin film 5 as a thin film (silicon) from becoming too thin than 2nm or more and 3nm or less, thereby ensuring that the desired thickness is formed.

[0067] Reference Figure 3 The third implementation plan will be explained.

[0068] The high mobility substrate of this embodiment is manufactured by the following method: after repeatedly forming silicon and further forming oxygen δ-doped layers on a first δ-doped layer with a thickness of 1 nm or more and 3 nm or less, a thin silicon film with a thickness of 2 nm or more and 3 nm or less is formed thereon.

[0069] Reference Figure 3 On the first δ-doped layer 6-1 of oxygen, silicon 7-1 is formed with a thickness of 1 nm or more and 3 nm or less, and oxygen δ-doped layer 6-2 is further formed. Silicon 7-2 is further formed with a thickness of 1 nm or more and 3 nm or less, and oxygen δ-doped layer 6-3 is further formed. Then, a thin film (silicon) 4 is formed on it with a thickness of 2 nm or more and 3 nm or less.

[0070] If this method is adopted, high mobility substrates can be reliably manufactured even with a stacked structure.

[0071] The repeated processing of silicon and δ-doped layers indicates that a stacked structure can be formed through repeated processing. On the other hand, in the CFET (Complementary Field Effect Transistor) structure, which is expected to be realized in the 2030s as a new generation of transistor structure, it is envisioned that a structure consisting of 3 or 4 stacked channels is formed in order to obtain sufficient current value. This embodiment can be applied to such a stacked structure.

[0072] Example

[0073] The following examples illustrate the present invention in detail, but are not intended to limit the scope of the invention.

[0074] [Example 1]

[0075] Example 1 is a manufacturing process implemented by carrying out the first embodiment described above. Figure 1 An example of a high mobility substrate is shown.

[0076] First, a silicon (110) single crystal substrate with a diameter of 300 nm, boron-doped p-type, and resistivity of 10 Ω·cm was prepared as the semiconductor substrate (support substrate) 2. It was immersed in a 1% hydrofluoric acid aqueous solution for 3 minutes to remove the native oxide film in one step, and then placed in the atmosphere (temperature 23℃±1℃, humidity 39%±3%) for 3 hours to form a first δ-doped oxygen layer 3-1. Then, it was placed in a reduced-pressure epitaxial growth apparatus, and a thin film (silicon) layer 4 was grown for 60 seconds at a temperature of 700℃, a pressure of 100 Torr, and a silane concentration of 1200 sccm. Then, it was removed from the apparatus and placed in the atmosphere for 1 hour, thereby forming a second δ-doped oxygen layer 3-2 on the surface side, obtaining a high-mobility substrate 1.

[0077] Regarding the high mobility substrate obtained here, the thickness of the first δ-doped layer, the thin film (silicon) layer, and the second δ-doped layer are all 3 nm, and the mobility is 100 cm⁻¹. 2 / V·s.

[0078] [Example 2]

[0079] Example 2 differs from Example 1 in that it adds the process of forming a δ-doped layer and a silicon layer.

[0080] A silicon (110) single crystal substrate with a diameter of 300 mm, boron-doped p-type, and resistivity of 10 Ω·cm was prepared as the semiconductor substrate (support substrate). It was immersed in a 1% hydrofluoric acid aqueous solution for 3 minutes to remove the native oxide film in one step, and then placed in the atmosphere (temperature 23℃±1℃, humidity 39%±3%) for 3 hours to form the first δ-doped oxygen layer. Then, it was placed in a reduced-pressure epitaxial growth apparatus and grown for 2 seconds at a temperature of 700℃, a pressure of 100 Torr, and a silane concentration of 1200 sccm. Then, it was removed from the apparatus and placed in the atmosphere for 1 hour to form the third δ-doped oxygen layer. Then, it was placed in a reduced-pressure epitaxial growth apparatus and grown for 2 seconds at a temperature of 700℃, a pressure of 100 Torr, and a silane concentration of 1200 sccm. Then, it is removed from the device and placed in the atmosphere for 1 hour to form a second δ-doped layer of oxygen on the surface side. It is then put into a reduced pressure epitaxial growth device and grown in 2 seconds under the conditions of 700°C, 100 Torr, and 1200 sccm of silane to obtain a high mobility substrate.

[0081] Regarding the high mobility substrate obtained here, the thickness of the first δ-doped layer, silicon layer, third δ-doped layer, thin film (silicon) layer, and second δ-doped layer is 3 nm, and the mobility is 100 cm⁻¹. 2 / V·s.

[0082] [Example 3]

[0083] Example 3 differs from Example 1 in that it adds the process of forming a δ-doped layer and a silicon layer, as well as the film formation conditions and the thermal oxidation of the thin film (silicon) in a heat treatment furnace to form a second δ-doped layer.

[0084] A silicon (110) single crystal substrate with a diameter of 300 mm, boron-doped p-type, and resistivity of 10 Ω·cm was prepared as the semiconductor substrate (support substrate). It was immersed in a 1% hydrofluoric acid aqueous solution for 3 minutes to remove the native oxide film in one step, and then placed in the atmosphere (temperature 23℃±1℃, humidity 39%±3%) for 3 hours to form the first δ-doped oxygen layer. Then, it was placed in a reduced-pressure epitaxial growth apparatus and grown for 2 seconds at a temperature of 700℃, a pressure of 100 Torr, and a silane concentration of 1200 sccm. Then, it was removed from the apparatus and placed in the atmosphere for 1 hour to form the third δ-doped oxygen layer. Then, it was placed in a reduced-pressure epitaxial growth apparatus and grown for 120 seconds at a temperature of 700℃, a pressure of 100 Torr, and a silane concentration of 1200 sccm. Then, it is removed from the device and placed in a heat treatment furnace for 5 minutes at 600°C in an oxygen atmosphere to form a second δ-doped layer of oxygen on the surface side, thereby obtaining a high mobility substrate.

[0085] Regarding the high mobility substrate obtained here, the thickness of the first δ-doped layer, silicon layer, third δ-doped layer, thin film (silicon) layer, and second δ-doped layer is 3 nm, and the mobility is 100 cm⁻¹. 2 / V·s.

[0086] The above results were examined.

[0087] Specifically regarding mobility, according to non-patent literature 3, the mobility of MoS2 in conventional two-dimensional materials is 50~100 cm⁻¹. 2 / V·s, while the mobility of the high mobility substrates obtained in Examples 1-3 is 100cm. 2 / V·s, therefore, embodiments 1 to 3 achieve mobility comparable to that of two-dimensional materials.

[0088] The above describes how the high mobility substrate and the manufacturing method of the high mobility substrate of the present invention can achieve high mobility and can be uniformly manufactured on the entire surface of a large-area substrate (large-diameter substrate), thus making it more practical.

[0089] Furthermore, by using a thin film layer that simulates a two-dimensional material, it is possible to form a high-migration channel material across the entire surface of a large-area substrate.

[0090] Furthermore, it is inexpensive because it can be implemented using conventional semiconductor materials such as silicon without using expensive two-dimensional materials such as MoS2.

[0091] The present invention includes the following solutions.

[0092] [1] A high mobility substrate, characterized in that it has:

[0093] Semiconductor substrate;

[0094] The band gap on the semiconductor substrate is larger than that of the first δ-doped layer of the semiconductor substrate;

[0095] A thin film of the same material as the semiconductor substrate on the first δ-doped layer;

[0096] The band gap on the thin film is larger than that of the second δ-doped layer of the semiconductor substrate.

[0097] The high mobility substrate is structured such that the thin film is sandwiched between the first δ-doped layer and the second δ-doped layer.

[0098] [2] The high mobility substrate according to [1] above is characterized in that,

[0099] The first δ-doped layer and the second δ-doped layer are δ-doped layers of oxygen.

[0100] The semiconductor substrate and the thin film are made of silicon.

[0101] The thickness of the film is greater than 2nm and less than 3nm.

[0102] [3] A method for manufacturing a high mobility substrate, characterized in that,

[0103] A first δ-doped layer with a band gap larger than that of the semiconductor substrate is formed on the semiconductor substrate.

[0104] A thin film of the same material as the semiconductor substrate is formed on the first δ-doped layer.

[0105] A second δ-doped layer with a band gap larger than that of the semiconductor substrate is formed on the thin film.

[0106] The thin film is sandwiched between the first δ-doped layer and the second δ-doped layer.

[0107] [4] The method for manufacturing a high mobility substrate according to [3] above is characterized in that,

[0108] The first δ-doped layer and the second δ-doped layer are set as δ-doped layers of oxygen.

[0109] The semiconductor substrate and the thin film are made of silicon.

[0110] The thickness of the film is set to be greater than 2 nm and less than 3 nm.

[0111] [5] The method for manufacturing a high mobility substrate according to [3] or [4] above is characterized in that,

[0112] During the formation of the film, a thickness that is anticipated to thin due to oxidation is formed.

[0113] The thin film is oxidized to form the second δ-doped layer.

[0114] [6] The method for manufacturing a high mobility substrate according to any one of [3] to [5], characterized in that,

[0115] After repeatedly forming silicon and further forming oxygen δ-doped layers on the first δ-doped layer with a thickness of more than 1 nm and less than 3 nm,

[0116] The thin film is formed on it with a thickness of more than 2 nm and less than 3 nm.

[0117] Furthermore, this invention is not limited to the above-described embodiments. The above embodiments are examples, and any solutions that have substantially the same composition and achieve the same effect as the technical concept described in the claims of this invention are included within the technical scope of this invention.

Claims

1. A high mobility substrate, characterized in that, It has the following characteristics: Semiconductor substrate; The band gap on the semiconductor substrate is larger than that of the first δ-doped layer of the semiconductor substrate; A thin film of the same material as the semiconductor substrate on the first δ-doped layer; The band gap on the thin film is larger than that of the second δ-doped layer of the semiconductor substrate. The high mobility substrate is structured such that the thin film is sandwiched between the first δ-doped layer and the second δ-doped layer.

2. The high mobility substrate according to claim 1, characterized in that, The first δ-doped layer and the second δ-doped layer are δ-doped layers of oxygen. The semiconductor substrate and the thin film are made of silicon. The thickness of the film is greater than 2nm and less than 3nm.

3. A method for manufacturing a high mobility substrate, characterized in that, A first δ-doped layer with a band gap larger than that of the semiconductor substrate is formed on the semiconductor substrate. A thin film of the same material as the semiconductor substrate is formed on the first δ-doped layer. A second δ-doped layer with a band gap larger than that of the semiconductor substrate is formed on the thin film. The thin film is sandwiched between the first δ-doped layer and the second δ-doped layer.

4. The method for manufacturing a high mobility substrate according to claim 3, characterized in that, The first δ-doped layer and the second δ-doped layer are set as δ-doped layers of oxygen. The semiconductor substrate and the thin film are made of silicon. The thickness of the film is set to be greater than 2 nm and less than 3 nm.

5. The method for manufacturing a high mobility substrate according to claim 3, characterized in that, During the formation of the film, a thickness that is anticipated to thin due to oxidation is formed. The thin film is oxidized to form the second δ-doped layer.

6. The method for manufacturing a high mobility substrate according to any one of claims 3 to 5, characterized in that, After repeatedly forming silicon and further forming oxygen δ-doped layers on the first δ-doped layer with a thickness of more than 1 nm and less than 3 nm, The thin film is formed on it with a thickness of more than 2 nm and less than 3 nm.

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