Method for enhancing hole linear rashba spin-orbit coupling effect

Abstract

The application provides a method for enhancing a hole linear Rashba spin-orbital coupling effect, which is based on a traditional germanium quantum well structure and one or more silicon atomic layers are inserted at an interface, so that the hole linear Rashba spin splitting can be improved by one order of magnitude. The application also provides a more optimal scheme for constructing a germanium quantum well by replacing a silicon germanium alloy barrier with a superlattice barrier, which can further improve the hole linear Rashba effect by several times on the basis of the interface quantum well scheme. The germanium quantum well structure disclosed by the application is deeply compatible with a CMOS process, and the one order of magnitude improvement of the hole linear Rashba effect will provide a brand-new solution for fast manipulation of a germanium quantum dot spin quantum bit.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to a method for fabricating a semiconductor germanium quantum well compatible with microelectronic CMOS technology, aiming to improve the spin-orbit coupling strength of the quantum well based on existing processes and promote the development of semiconductor quantum computing. Background Technology

[0002] In recent years, the spin-orbit coupling effect of holes has become a key research topic in semiconductor quantum computing. Especially for germanium, which is deeply compatible with microelectronic CMOS processes, holes offer numerous advantages over electrons, including zero-nuclear spin scattering, long decoherence time, strong spin-orbit coupling, rapid spin manipulation, immunity to valley degeneracy and scattering, and electrically controllability without requiring a gradient magnetic field from a micromagnetic structure. The spin-orbit coupling effect can be divided into the Rashba effect and the Dresselhaus effect. The former is caused by the breaking of potential symmetry at the interface of a low-dimensional system and can be controlled by an external electric field, while the latter is caused by the intrinsic atomic chemical potential asymmetry of the material. Recent research shows that a first-order linear Rashba spin-orbit coupling effect exists in germanium quantum wells, which is the main source driving the rapid flipping of spin qubits. Therefore, improving the linear Rashba strength of holes in germanium quantum wells has become an important issue.

[0003] Although recent studies have shown that the linear Rashba effect of holes in germanium quantum wells can be modulated by the growth direction of the quantum well and reaches its maximum value in the

[110] direction, current mature microelectronic CMOS processes can only grow quantum wells in the

[001] direction. The barrier material of this quantum well is composed of a silicon-germanium alloy, in which the silicon content is between 10% and 50%. Using a silicon-germanium alloy as the barrier material can, on the one hand, provide a quantum binding effect to confine holes, and on the other hand, eliminate or reduce the lattice mismatch between germanium and silicon, thereby improving sample quality. Considering the practical feasibility of microelectronic processes, the problem of improving the linear Rashba intensity can be further refined to how to modify germanium quantum wells based on existing mature microelectronic processes to improve the Rashba intensity.

[0004] Although the linear Rashba effect of germanium quantum wells plays a crucial role in quantum computing, it has not been successfully detected experimentally to date. There are two main reasons for this: First, the hole concentration in experimentally prepared germanium quantum wells is high, causing the Fermi momentum to deviate far from the center of the Brillouin zone, while the linear effect can only be clearly observed near the center of the Brillouin zone. Second, the linear Rashba effect generated by the currently prepared germanium quantum well structures is not strong enough, which seriously limits the development of semiconductor quantum computing. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] The purpose of this invention is to provide a scheme for enhancing the hole linear Rashba spin-orbit coupling strength at the interface of a semiconductor germanium quantum well compatible with microelectronic CMOS processes, in order to solve the problem that the hole linear Rashba effect in the quantum well cannot be measured experimentally and to further improve the speed of hole spin qubit manipulation in gated quantum dots.

[0007] One embodiment of this application proposes a method for enhancing the hole linear Rashba spin-orbit coupling effect, comprising:

[0008] Provide substrate;

[0009] A germanium quantum well is formed on the substrate, wherein a silicon atomic layer is formed at the interface between the potential well and the potential barrier of the germanium quantum well, wherein the silicon atomic layer comprises one or more monoatom layers.

[0010] In some embodiments, a germanium quantum well is formed on the substrate, including:

[0011] A first alloy layer is formed on the substrate;

[0012] A first silicon atom layer is formed on the first alloy layer, wherein the first silicon atom layer comprises one or more monoatom layers;

[0013] A germanium layer is formed on top of the first silicon atomic layer;

[0014] A second silicon atomic layer is formed on the germanium layer, wherein the second silicon atomic layer comprises one or more monoatom layers;

[0015] A second alloy layer is formed on top of the second silicon atom layer.

[0016] In some embodiments, a germanium quantum well is formed on the substrate, including:

[0017] A first silicon-germanium superlattice is formed on the substrate, wherein the first silicon-germanium superlattice includes one or more single-atom layers of silicon;

[0018] A germanium layer is formed on the first silicon-germanium superlattice;

[0019] A second silicon-germanium superlattice is formed on the germanium layer, wherein the second silicon-germanium superlattice includes one or more single-atom layers of silicon.

[0020] In some embodiments, it also includes:

[0021] A dielectric layer is formed on the germanium quantum well;

[0022] Electrodes are formed on the dielectric layer.

[0023] In some embodiments, the substrate is a silicon substrate.

[0024] In some embodiments, the thickness of the germanium layer is 10 nanometers to 20 nanometers.

[0025] In some embodiments, the first alloy layer is a first silicon-germanium alloy layer, the second alloy layer is a second silicon-germanium alloy layer, the silicon content in each silicon-germanium alloy layer is between 10% and 50%, and the thickness of each silicon-germanium alloy layer is tens of nanometers.

[0026] In some embodiments, the thickness of both the first silicon atomic layer and the second silicon atomic layer is 1 to 4 single atomic layers.

[0027] In some embodiments, the thickness of both the first silicon-germanium superlattice and the second silicon-germanium superlattice is tens of nanometers, wherein the number of single atomic layers of silicon or germanium is 1-4 layers.

[0028] In some embodiments, the dielectric material of the dielectric layer is SiO2 or Al2O3, and the thickness of the dielectric layer is between tens of nanometers and hundreds of nanometers.

[0029] In some embodiments, the electrode is a metal electrode, the material of which is Al or Au, and the thickness of the electrode is on the order of tens of nanometers.

[0030] In some embodiments, the bulk phases of germanium and silicon materials in the germanium quantum well are both crystal structures with tetrahedral covalent bonds.

[0031] In some embodiments, the hole concentration of the germanium quantum well reaches 10. 10 cm -2 On the order of magnitude, the mobility of quantum wells reaches 10-1. 5 cm 2 On the order of / (V·s).

[0032] Another embodiment of this application provides a semiconductor structure comprising: a substrate and a germanium quantum well formed on the substrate, wherein a silicon atomic layer is formed at the interface between the potential well and the potential barrier of the germanium quantum well, wherein the silicon atomic layer comprises one or more monoatom layers.

[0033] In some embodiments, the germanium quantum well includes, from bottom to top, a substrate, a first alloy layer, a first silicon atomic layer, a germanium layer, a second silicon atomic layer, a second alloy layer, a dielectric layer, and a metal electrode, wherein the first silicon atomic layer and the second silicon atomic layer each include one or more monoatom layers.

[0034] In some embodiments, the germanium quantum well includes a substrate, a first silicon-germanium superlattice, a germanium layer, a second silicon-germanium superlattice, a dielectric layer, and a metal electrode formed sequentially from bottom to top, wherein the first silicon-germanium superlattice and the second silicon-germanium superlattice each include one or more single-atom layers of silicon.

[0035] In some embodiments, the substrate is a silicon substrate.

[0036] In some embodiments, the first alloy layer is a first silicon-germanium alloy layer, the second alloy layer is a second silicon-germanium alloy layer, the silicon content in each silicon-germanium alloy layer is between 10% and 50%, and the thickness of each silicon-germanium alloy layer is tens of nanometers.

[0037] In some embodiments, the thickness of both the first silicon atomic layer and the second silicon atomic layer is 1 to 4 single atomic layers.

[0038] In some embodiments, the thickness of both the first silicon-germanium superlattice and the second silicon-germanium superlattice is tens of nanometers, wherein the number of single atomic layers of silicon or germanium is 1-4 layers.

[0039] In some embodiments, the bulk phases of germanium and silicon materials in the germanium quantum well are both crystal structures with tetrahedral covalent bonds.

[0040] The beneficial effects of this invention are as follows:

[0041] 1. This invention points out that the silicon-germanium alloy barrier of the germanium quantum well will significantly reduce the hole linear Rashba spin-orbit coupling effect, and proposes that the Rashba strength can be increased by an order of magnitude by inserting one or more silicon atomic layers at the interface.

[0042] 2. This invention proposes a method for interface engineering and superlattice barriers, which solves the problem of difficulty in growing germanium quantum wells with the maximum Rashba effect in the

[110] direction.

[0043] 3. The germanium quantum well involved in this invention is deeply compatible with existing mature microelectronic CMOS processes and is expected to be used to further improve the manipulation speed of semiconductor quantum dot spin qubits.

[0044] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0045] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings.

[0046] in:

[0047] Figure 1This is a schematic diagram of a germanium quantum well according to an embodiment of the present invention;

[0048] Figure 2 shows the relationship between the hole spin splitting size and the wave vector in the germanium quantum well according to an embodiment of the present invention, wherein:

[0049] Figure 2a This is a graph showing the relationship between the size of hole spin splitting and the wave vector in a germanium quantum well without silicon atomic layers.

[0050] Figure 2b The graph shows the relationship between the size of hole spin splitting and the wave vector in a germanium quantum well containing silicon atomic layers.

[0051] Figure 3 shows the relationship between the corresponding linear Rashba parameter in the germanium quantum well of this invention and the variation of silicon composition in the alloy barrier, as well as the variation of the number of silicon atomic layers at the interface.

[0052] Figure 3a The graph shows the relationship between the corresponding linear Rashba parameter in the germanium quantum well and the silicon composition in the silicon-germanium alloy barrier.

[0053] Figure 3b The graph shows the relationship between the corresponding linear Rashba parameter and the number of interfacial silicon atomic layers in the germanium quantum well.

[0054] Figure 4 This is a schematic diagram of the structure of a germanium quantum well with a silicon-germanium superlattice barrier according to an embodiment of the present invention;

[0055] Figure 5 for Figure 4 The relationship between the linear Rashba parameter and the number of silicon or germanium atomic layers in the silicon-germanium superlattice in the scheme is shown in the figure.

[0056] Figure label:

[0057] 1-Metal electrode; 2-Dielectric layer; 3-Second silicon-germanium alloy layer; 4-Second silicon atom layer; 5-Germanium layer; 6-First silicon atom layer; 7-First silicon-germanium alloy layer; 8-Silicon substrate; 9-First silicon-germanium superlattice; 10-Second silicon-germanium superlattice. Detailed Implementation

[0058] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0059] In view of the shortcomings described in the background art, this invention provides a method for enhancing the linear Rashba spin-orbit coupling effect of holes using a germanium quantum well interface, which is deeply compatible with CMOS technology, and can achieve an order-of-magnitude improvement in Rashba strength. This method will facilitate the rapid manipulation of spin qubits in quantum computing.

[0060] Germanium, silicon, and other Group IV elements exhibit weak nuclear spin scattering, and the influence of nuclear spin can be further reduced through isotope purification techniques, resulting in long spin decoherence times. Germanium holes possess strong spin-orbit coupling while remaining unaffected by valley degeneracy and valley scattering. Furthermore, germanium materials benefit from well-established microelectronics processes. Therefore, hole-based quantum well systems have become a hot topic in semiconductor quantum computing. Currently, the fabrication, manipulation, and readout of four qubits in germanium quantum well systems have been achieved internationally. Notably, recent research indicates that the linear Rashba spin-orbit coupling effect of holes in germanium quantum wells can drive rapid flipping of spin qubits. High-quality spin qubits require fast spin manipulation rates, and improving these rates hinges on increasing the linear Rashba strength of holes.

[0061] The core idea of ​​this invention lies in improving the quantum well structure design by inserting one or more silicon atom layers at the interface between the potential well and the barrier in a traditional germanium quantum well, thereby achieving a significant enhancement of the hole Rashba effect. Using first-principles empirical pseudopotential methods, the electronic structure of germanium quantum wells with silicon-germanium alloy barriers of different compositions was calculated. It was found that the linear Rashba parameter decreases as the silicon content in the alloy barrier decreases. For the silicon-germanium alloy barrier with a commonly used silicon content of 20%, the linear Rashba parameter is only about one-tenth that of the pure silicon barrier. By inserting one or more silicon atom layers at the interface between the potential well and the barrier, it was found that the linear Rashba parameter can be increased to the level of Si. 0.2 Ge 0.8 The Rashba parameter of the alloy barrier is about ten times that of the pure silicon barrier.

[0062] Furthermore, this invention provides an even better solution, which replaces the original silicon-germanium alloy barrier with a silicon-germanium superlattice barrier. This better solution can further improve the hole linear Rashba parameter by two to three times based on the interface engineering approach. Since germanium quantum wells with pure silicon barriers are difficult to grow in reality due to lattice mismatch, the interface engineering approach proposed in this invention to improve the hole linear Rashba effect in quantum wells has a strong practical basis and significant demand orientation.

[0063] This invention is compatible with existing mature microelectronic CMOS processes and proposes a scheme to enhance the linear Rashba effect of holes in germanium quantum wells through interface enhancement, which is beneficial for realizing fast manipulation of spin qubits by utilizing this enhanced Rashba effect.

[0064] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0065] like Figure 1 As shown, one embodiment of this application proposes a method for enhancing the linear Rashba spin-orbit coupling effect of holes using a germanium quantum well interface, involving the key step of inserting one or more silicon atomic layers at the interface between the potential well and the potential barrier of the germanium quantum well, wherein the silicon atomic layers include one or more monoatom layers.

[0066] The preparation method of this quantum well mainly includes the following steps:

[0067] S1, A first silicon-germanium alloy layer 7 is grown on a silicon substrate 8 to reduce the lattice mismatch between germanium and silicon. The silicon content in the first silicon-germanium alloy layer 7 is between 10% and 50%, and the thickness of the first silicon-germanium alloy layer 7 is about tens of nanometers.

[0068] S2, a first silicon atomic layer 6 is epitaxially or deposited on the first silicon-germanium alloy layer 7, wherein the first silicon atomic layer 6 comprises 1-4 single atomic layers;

[0069] S3, a germanium layer 5 is grown on the first silicon atomic layer 6, the thickness of the germanium layer 5 being approximately 10 nanometers to 20 nanometers;

[0070] S4, a second silicon atomic layer 4 is epitaxially or deposited on the germanium layer 5, wherein the second silicon atomic layer 4 comprises 1-4 single atomic layers;

[0071] S5, a second silicon-germanium alloy layer 3 is grown on the second silicon atomic layer 4, wherein the silicon content in the second silicon-germanium alloy layer 3 is between 10% and 50%, and the thickness of the second silicon-germanium alloy layer 3 is about tens of nanometers.

[0072] S6, a dielectric layer 2 is grown on the second silicon-germanium alloy layer 3. The dielectric material of the dielectric layer 2 can be SiO2 or Al2O3, and the thickness of the dielectric layer 2 is between tens of nanometers and tens of nanometers.

[0073] S7. A metal electrode 1 is fabricated on dielectric layer 2. The material of metal electrode 1 can be Al or Au, and the thickness of metal electrode 1 is on the order of tens of nanometers. The Rashba spin-orbit coupling effect is generated and modulated by applying a gate voltage to metal electrode 1.

[0074] In the embodiments of the present invention, the germanium layer in the germanium quantum well has a thickness of 16 nanometers, and a vertical electric field with an intensity of 30 kV / cm is applied, that is, it is subjected to quantum binding effect in the direction perpendicular to the plane. The biaxial compressive strain of the silicon substrate on the germanium quantum well is 0.6%. Figure 2a and Figure 2bThis is a graph showing the relationship between the size of hole spin splitting and the wave vector in a germanium quantum well according to an embodiment of the present invention. Figure 3a and Figure 3b The graph shows the relationship between the corresponding linear Rashba parameter in the germanium quantum well of this invention and the changes in the silicon composition in the alloy barrier, as well as the changes in the number of silicon atomic layers at the interface. Figure 3a and Figure 3b The linear Rashba parameter α obtained from R can be Figure 2a and Figure 2b The heavy cavity spin splitting ΔE in the region near the center of the Brillouin zone is shown. SS =2α R k || Thus, the magnitude of the linear Rashba parameter can be used to characterize the strength of the Rashba effect. Figure 2a and Figure 3a The linear Rashba effect without an interfacial silicon atomic layer is described. When the silicon content in the alloy barrier is 20%, the linear Rashba parameter is only 0.21 meV; when the silicon content in the alloy barrier is 50%, the linear Rashba parameter is 0.96 meV; when the silicon content in the alloy barrier is 80%, the linear Rashba parameter is 1.36 meV; and for a pure silicon barrier, the linear Rashba parameter is 2.01 meV. Figure 2a and Figure 3a The calculation results show that the linear Rashba parameter gradually increases with the increase of silicon content in the alloy barrier.

[0075] However, in reality, to reduce the lattice mismatch between silicon and germanium, the silicon content in the alloy barrier is often between 10% and 50%, typically around 20%. The embodiments of this invention consider the presence of silicon in Si... 0.2 Ge 0.8 One or more silicon atom layers are inserted at the interface of the germanium quantum well with alloy barrier. Figure 2b and Figure 3b The results for the corresponding spin splitting and linear Rashba parameters show that inserting 1, 2, and 4 silicon atomic layers yields linear Rashba parameters of 1.75 meV, 2.06 meV, and 2.07 meV, respectively, which are close to the linear Rashba parameter values ​​of an ideal pure silicon barrier and are an order of magnitude larger than the linear Rashba parameter of a germanium quantum well without silicon atomic layers inserted at the interface.

[0076] like Figure 4 As shown, the present invention proposes a better solution based on the above solution, namely, using a silicon-germanium superlattice barrier to replace the silicon-germanium alloy barrier, while still ensuring one or more silicon atom layers at the germanium potential well interface.

[0077] The preparation method of this quantum well mainly includes the following steps:

[0078] S1, A first silicon-germanium superlattice 9 is epitaxially or deposited on a silicon substrate 8. The first silicon-germanium superlattice (Si) n / (Ge) n The number of single atomic layers n in silicon or germanium is between 1 and 4, and the thickness of the first silicon-germanium superlattice 9 is about tens of nanometers.

[0079] S2, a germanium layer 5 is grown on the first silicon-germanium superlattice 9, the thickness of the germanium layer 5 being approximately 10 nanometers to 20 nanometers.

[0080] S3, a second silicon-germanium superlattice 10 is epitaxially or deposited on the germanium layer 5, wherein the second silicon-germanium superlattice (Si) n / (Ge) n The number of single-atom layers n in the medium silicon or germanium is between 1 and 4, and the thickness of the second silicon-germanium superlattice 10 is about tens of nanometers.

[0081] S4. A dielectric layer 2 is grown on the second silicon-germanium superlattice 10. The dielectric material of the dielectric layer 2 can be SiO2 or Al2O3, and the thickness of the dielectric layer 2 is between tens of nanometers and tens of nanometers.

[0082] S5, a metal electrode 1 is fabricated on dielectric layer 2. The material of metal electrode 1 can be Al or Au, and the thickness of metal electrode 1 is on the order of tens of nanometers. The Rashba spin-orbit coupling effect is generated and modulated by applying a gate voltage to metal electrode 1.

[0083] In the embodiments of the present invention, the germanium layer in the germanium quantum well has a thickness of 16 nanometers, and a vertical electric field with an intensity of 30 kV / cm is applied, that is, it is subjected to quantum binding effect in the direction perpendicular to the plane. The biaxial compressive strain of the silicon substrate on the germanium quantum well is 0.6%. Figure 5 The diagram shows the relationship between the linear Rashba parameter and the number of silicon or germanium atomic layers in the silicon-germanium superlattice, representing a preferred embodiment of the present invention. For germanium quantum wells with (Si)1 / (Ge)1, (Si)2 / (Ge)2, and (Si)4 / (Ge)4 superlattice barriers, the corresponding linear Rashba parameters are 6.91 meV, 3.97 meV, and 2.35 meV, respectively. These are all larger than the linear Rashba parameters of germanium quantum wells with pure silicon barriers, and also two to three times larger than the linear Rashba parameters of the interface-alloy barrier system in the aforementioned embodiments of the present invention. Figure 5 This indicates that the linear Rashba parameter decreases as the number of silicon and germanium atomic layers in the silicon-germanium superlattice increases. Therefore, germanium quantum wells with (Si)1 / (Ge)1 superlattice barriers are superior to Si quantum wells without the currently commonly used interface silicon atomic layers. 0.2 Ge 0.8The germanium quantum well with alloy barrier exhibits an approximately 30-fold improvement in linear Rashba effect, resulting in the strongest linear Rashba effect.

[0084] Two-dimensional gated germanium quantum dots fabricated based on germanium quantum wells can be used for quantum computing, where the qubits are the spins at the lowest energy level of the holes in the quantum dot. The manipulation rate of spin qubits is proportional to the linear Rashba effect; therefore, the scheme provided in this invention for enhancing the linear Rashba effect at the germanium quantum well interface will help to further improve the manipulation rate of spin qubits.

[0085] In summary, this invention provides a method for enhancing the linear Rashba spin-orbit coupling effect of holes using the interface of a germanium quantum well. This method is compatible with CMOS technology and inserts one or more silicon atom layers at the interface on the basis of the traditional germanium quantum well structure, which can achieve an order of magnitude improvement in the linear Rashba spin splitting of holes and will help improve the manipulation rate of the spin qubits of two-dimensional gated germanium quantum dots.

[0086] In some specific embodiments, the substrate is not limited to a silicon substrate.

[0087] In some specific embodiments, a silicon-germanium superlattice (Si) n / (Ge) n It could also be (Ge) m / (Si) n Even if germanium and silicon have different numbers of single atomic layers (m≠n), the corresponding effect can still be achieved. That is, only one silicon atomic layer is needed at the interface to achieve the technical effect described in this invention.

[0088] In some specific embodiments, the bulk phases of germanium and silicon materials in the germanium quantum well are both crystal structures with tetrahedral covalent bonds.

[0089] In some specific embodiments, silicon atomic layers are grown on silicon-germanium alloy layers by molecular beam epitaxy or vapor deposition.

[0090] In some specific embodiments, the hole concentration of the germanium quantum well reaches 10-1. 10 cm -2 On the order of magnitude, the mobility of germanium quantum wells reaches 10-1. 5 cm 2 On the order of / (V·s).

[0091] Another embodiment of this application proposes a semiconductor structure, such as Figure 1As shown, the device includes a silicon substrate 8 and a germanium quantum well formed on the silicon substrate 8, wherein a silicon atom layer is formed at the interface between the potential well and the potential barrier of the germanium quantum well. Specifically, it includes, from bottom to top, the following layers: silicon substrate 8, first silicon-germanium alloy layer 7, first silicon atom layer 6, germanium layer 5, second silicon atom layer 4, second silicon-germanium alloy layer 3, dielectric layer 2, and metal electrode 1. The first silicon atom layer 6 and the second silicon atom layer 4 each consist of 1-4 monolayers. The silicon content in each silicon-germanium alloy layer is between 10% and 50%, and the thickness of each silicon-germanium alloy layer is tens of nanometers. The bulk phases of the germanium and silicon materials in the germanium quantum well are both crystalline structures with tetrahedral covalent bonds. The thickness of the germanium layer is 10 to 20 nanometers. The dielectric material of the dielectric layer is SiO2 or Al2O3, and the thickness of the dielectric layer is between tens of nanometers. The material of the metal electrode 1 is Al or Au, and the thickness of the metal electrode 1 is on the order of tens of nanometers.

[0092] A better semiconductor structure scheme is also proposed, such as... Figure 4 As shown, the structure includes, from bottom to top, a silicon substrate 8, a first silicon-germanium superlattice 9, a germanium layer 5, a second silicon-germanium superlattice 10, a dielectric layer 2, and a metal electrode 1. Both the first silicon-germanium superlattice 9 and the second silicon-germanium superlattice 10 contain 1-4 single-atom layers of silicon or germanium. The thickness of both the first silicon-germanium superlattice 9 and the second silicon-germanium superlattice 10 is tens of nanometers. The bulk phases of the germanium and silicon materials in the germanium quantum well are both crystalline structures with tetrahedral covalent bonds. The thickness of the germanium layer 5 is 10 to 20 nanometers. The dielectric material of the dielectric layer 2 is SiO2 or Al2O3, and the thickness of the dielectric layer 2 is between tens of nanometers. The material of the metal electrode 1 is Al or Au, and the thickness of the metal electrode 1 is on the order of tens of nanometers.

[0093] In some specific embodiments, both the first silicon-germanium superlattice 9 and the second silicon-germanium superlattice 10 may include at least one single-atom layer of silicon.

[0094] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0095] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0096] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0097] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0098] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0099] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for enhancing the hole linear Rashba spin-orbit coupling effect, characterized in that, include: Provide substrate; A germanium quantum well is formed on the substrate, wherein a silicon atomic layer is formed at the interface between the potential well and the potential barrier of the germanium quantum well, wherein the silicon atomic layer comprises one or more monoatom layers. Forming a germanium quantum well on the substrate includes: A first alloy layer is formed on the substrate; A first silicon atom layer is formed on the first alloy layer, wherein the first silicon atom layer comprises one or more monoatom layers; A germanium layer is formed on top of the first silicon atomic layer; A second silicon atomic layer is formed on the germanium layer, wherein the second silicon atomic layer comprises one or more monoatom layers; A second alloy layer is formed on top of the second silicon atomic layer; or Forming a germanium quantum well on the substrate includes: A first silicon-germanium superlattice is formed on the substrate, wherein the first silicon-germanium superlattice includes one or more silicon atom layers, and the silicon atom layers include one or more monoatom layers; A germanium layer is formed on the first silicon-germanium superlattice; A second silicon-germanium superlattice is formed on the germanium layer, wherein the second silicon-germanium superlattice includes one or more silicon atom layers, and the silicon atom layers include one or more monoatom layers.

2. The method as described in claim 1, characterized in that, Also includes: A dielectric layer is formed on the germanium quantum well; Electrodes are formed on the dielectric layer.

3. The method according to any one of claims 1-2, characterized in that, The substrate is a silicon substrate.

4. The method as described in claim 1, characterized in that, The germanium layer has a thickness of 10 nanometers to 20 nanometers.

5. The method as described in claim 1, characterized in that, The first alloy layer is a first silicon-germanium alloy layer, the second alloy layer is a second silicon-germanium alloy layer, the silicon content in each silicon-germanium alloy layer is between 10% and 50%, and the thickness of each silicon-germanium alloy layer is tens of nanometers.

6. The method as described in claim 1, characterized in that, The thickness of both the first silicon atomic layer and the second silicon atomic layer is 1 to 4 single atomic layers.

7. The method as described in claim 1, characterized in that, The thickness of both the first and second silicon-germanium superlattices is tens of nanometers, and the number of single-atom layers of silicon atoms is 1-4.

8. The method as described in claim 2, characterized in that, The dielectric material of the dielectric layer is SiO2 or Al2O3, and the thickness of the dielectric layer is between tens of nanometers and hundreds of nanometers.

9. The method as described in claim 2, characterized in that, The electrode is a metal electrode, and the material of the metal electrode is Al or Au. The thickness of the electrode is on the order of tens of nanometers.

10. The method as described in claim 1, characterized in that, The bulk phases of germanium and silicon materials in the germanium quantum well are both crystal structures with tetrahedral covalent bonds.

11. The method as described in claim 1, characterized in that, The hole concentration of the germanium quantum well reaches 10. 10 cm -2 On the order of magnitude, the mobility of germanium quantum wells reaches 10-1. 5 cm 2 / (V (s) magnitude.

12. A semiconductor structure, characterized in that, The semiconductor structure is prepared according to the method of any one of claims 1-11, and comprises: Substrate; A germanium quantum well is formed on the substrate, wherein a silicon atomic layer is formed at the interface between the potential well and the potential barrier of the germanium quantum well, wherein the silicon atomic layer comprises one or more monoatom layers.

13. The semiconductor structure as described in claim 12, characterized in that, The germanium quantum well comprises, from bottom to top, a substrate, a first alloy layer, a first silicon atomic layer, a germanium layer, a second silicon atomic layer, a second alloy layer, a dielectric layer, and a metal electrode, wherein the first silicon atomic layer and the second silicon atomic layer each comprise one or more monolayers.

14. The semiconductor structure as claimed in claim 12, characterized in that, The germanium quantum well comprises, from bottom to top, a substrate, a first silicon-germanium superlattice, a germanium layer, a second silicon-germanium superlattice, a dielectric layer, and a metal electrode, wherein the first silicon-germanium superlattice and the second silicon-germanium superlattice each include one or more silicon atom layers, and the silicon atom layers include one or more monoatom layers.

15. The semiconductor structure as described in claim 13 or 14, characterized in that, The substrate is a silicon substrate.

16. The semiconductor structure as described in claim 13, characterized in that, The first alloy layer is a first silicon-germanium alloy layer, the second alloy layer is a second silicon-germanium alloy layer, the silicon content in each silicon-germanium alloy layer is between 10% and 50%, and the thickness of each silicon-germanium alloy layer is tens of nanometers.

17. The semiconductor structure as claimed in claim 13, characterized in that, The thickness of both the first silicon atomic layer and the second silicon atomic layer is 1 to 4 single atomic layers.

18. The semiconductor structure as described in claim 14, characterized in that, The thickness of both the first and second silicon-germanium superlattices is tens of nanometers, and the number of single-atom layers of silicon atoms is 1-4.

19. The semiconductor structure as described in claim 13 or 14, characterized in that, The bulk phases of germanium and silicon materials in the germanium quantum well are both crystal structures with tetrahedral covalent bonds.

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