A method for remote epitaxial preparation of nitride thin films based on polarization effect

Abstract

The application discloses a preparation method of a nitride film based on a polarization effect, and relates to the technical field of semiconductor materials. 1‑x M x A polarization layer doped with N, wherein x is any value ranging from 0.15 to 0.45, and the polarization layer is grown on Al 1‑x M x A platinum electrode layer is prepared on the surface of the polarization layer doped with N, and a current and an external electric field are applied to the platinum electrode layer, so that the electric field acts on the polarization layer doped with N to regulate a ferroelectric polarization effect and adjust the polarization intensity of the polarization layer doped with N to be any value ranging from 0.1 muC / cm 2 -250 muC / cm 2 ; the platinum electrode layer is etched to expose the polarization layer doped with N in a polarization state; and a two-dimensional material layer and a nitride film layer are sequentially grown on the surface of the polarization layer doped with N to obtain a nitride film. The preparation method can significantly enhance the polarization intensity of a composite substrate and avoid the problem of crystal quality caused by weakening of the substrate polarity by the two-dimensional material layer.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and in particular to a remote epitaxial preparation method of a nitride film based on a polarization effect. Background Art

[0002] Remote epitaxy involves growing or transferring a few layers of graphene onto a substrate. The electrostatic potential of the substrate can act on the epitaxial layer through the graphene. When the force exerted by the substrate on the epitaxial layer is much greater than that exerted by the two-dimensional material, the orientation of the GaN epitaxial layer is no longer dominated by the inserted two-dimensional material, but is instead determined by the remote electrostatic force of the substrate, with the epitaxial layer strictly adhering to the lattice information of the substrate. The magnitude of the remote epitaxial force lies between van der Waals forces and covalent forces, which makes the crystal orientation in the GaN epitaxial layer more consistent, alleviating the problems of in-plane rotation angles and large-angle grain boundaries in van der Waals epitaxy, while retaining the advantages of van der Waals epitaxy in that the epitaxial layer can be peeled off and that the lattice and thermal mismatch between the substrate and the epitaxial layer can be alleviated. Remote epitaxy has become a very promising method for growing single-crystal electronics and optoelectronics.

[0003] Prior art typically utilizes ferroelectric materials with strong polarization effects as polar substrates to control the deposition quality of remote epitaxial nitride films. Examples of these materials include LiNbO3, BaTiO3, SrTiO3, KNbO3, or PZT. However, the high deposition temperature during the preparation of the GaN epitaxial layer within the nitride film can cause the ferroelectric polarization of some ferroelectric materials to disappear, thereby affecting the quality of the subsequent nitride epitaxial layer growth. Summary of the Invention

[0004] One purpose of the present invention is to provide a remote epitaxial preparation method for nitride thin films based on the polarization effect, so as to solve the technical problem in the prior art that the polarity of the polar substrate in the remote epitaxial preparation process of nitride thin films is weak and the two-dimensional material layer cannot be avoided, which leads to poor crystal quality.

[0005] Another object of the present invention is to prevent the polarization performance from being affected during the deposition of nitride films.

[0006] According to the purpose of the present invention, the present invention provides a remote epitaxial preparation method of a nitride thin film based on the polarization effect, comprising:

[0007] Growth of Al on pretreated substrates 1-x M x N-doped polarization layer, x is any value in the range of 0.15-0.45, and the element M is any one of Sc, Y, La, Nd, Gd, Dy, Er, Yb, and Lu;

[0008] In the Al 1-x M xA platinum electrode layer with a thickness of 50 nm to 100 nm is prepared on the surface of the N-doped polarization layer, and a current density of 10 mA / cm is applied to the platinum electrode layer. 2 -30mA / cm 2 The electric field is any value in the range of -10MV / cm to 10MV / cm, so that the electric field acts on the Al 1-x M x The N-doped polarization layer regulates the ferroelectric polarization effect and adjusts the Al 1-x M x The polarization strength of the N-doped polarization layer is 0.1 μC / cm 2 -250μC / cm 2 Any value in

[0009] The platinum electrode layer is etched to expose the Al in a polarized state. 1-x M x N-doped polarization layer;

[0010] In the polarized state of the Al 1-x M x A two-dimensional material layer and a nitride film layer are sequentially grown on the surface of the N-doped polarization layer to prepare the nitride thin film. The growth temperature of the nitride film layer is any value between 600°C and 1200°C.

[0011] Optionally, the step of etching the platinum electrode layer further includes:

[0012] The platinum electrode layer is removed by wet etching, wherein the wet etching solution comprises potassium iodide with a concentration of any value between 0.5 mol / L and 1.0 mol / L and iodine element with a concentration of any value between 0.05 mol / L and 0.1 mol / L.

[0013] Optionally, the etching time of the wet etching is any value between 30s and 90s.

[0014] Optionally, the substrate is made of any one of sapphire, silicon, silicon carbide, diamond, aluminum nitride, gallium nitride or molybdenum.

[0015] Optionally, the Al 1-x M x The N-doped polarization layer is grown by any one of metal organic chemical vapor deposition, molecular beam epitaxy or magnetron sputtering.

[0016] Optionally, the Al 1-x M xThe growth temperature of the N-doped polarization layer is any value between 450° C. and 550° C., the growth pressure is any value between 0.5 Pa and 2.0 Pa, and the radio frequency power is any value between 100 W and 200 W.

[0017] Optionally, the two-dimensional material layer is made of any one of graphene, hexagonal boron nitride or transition metal sulfide.

[0018] Optionally, the two-dimensional material layer is grown by chemical vapor deposition or molecular beam epitaxy.

[0019] Optionally, the thickness of the two-dimensional material layer is any value between 0.34 nm and 1 nm.

[0020] The present invention utilizes Al 1-x M x The N-doped polarization layer is used as the polarization substrate, and the Al 1- x M x The piezoelectric coefficient d of aluminum nitride material 33 , and then to the Al with ferroelectric polarization effect 1-x M x The platinum electrode layer on the surface of the N-doped polarization layer applies a certain current density and an external electric field to regulate the Al 1-x M x The ferroelectric polarization effect of the N-doped polarization layer is achieved by adjusting the Al 1-x M x The center offset of positive and negative ions in the N-doped polarization layer produces a larger polarization electric field to regulate the polarization intensity of the ferroelectric polarization effect, thereby enhancing the overall polarity of the composite substrate, so that the polarity of the composite substrate penetrates the two-dimensional material layer and acts on the epitaxial growth process of the nitride film, avoiding the crystal quality problem caused by the two-dimensional material layer weakening the polarity of the substrate, which is conducive to obtaining low stress, low defect density, and strippable high-quality nitride films.

[0021] Furthermore, the present invention removes the platinum electrode layer by wet etching, and sets the concentrations of potassium iodide and iodine in the etching solution used for etching the platinum electrode layer within the above range. The KI / I2 etching solution has a high etching selectivity for metal platinum, which can ensure that the platinum electrode layer is etched rather than the doped polarization layer is damaged. The complex reaction formed by KI / I2 controls the etching rate to be moderate, which can avoid excessively high concentrations causing excessive etching and damaging the underlying Al layer. 1-x M x N-doped polarization layer, or too low concentration leads to incomplete etching or residual platinum electrode, thereby preventing the subsequent polarization performance from being affected.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0024] Figure 1 is a schematic flow chart of a nitride film according to one embodiment of the present invention;

[0025] Figure 2 is the relationship between the polarization intensity and u value of the AlN unit cell;

[0026] Figure 3 This is the relationship between the interface binding energy and u value of the single-layer graphene / AlN heterojunction structure;

[0027] Figure 4 This is the relationship between the change in graphene charge and the u value in the single-layer graphene / AlN heterojunction structure;

[0028] Figure 5 is a schematic structural diagram of a nitride film according to one embodiment of the present invention;

[0029] Figure 6 is an Al according to an embodiment of the present invention 1-x Sc x Hysteresis loops of N at different Sc compositions.

[0030] Reference numerals:

[0031] 100-nitride thin film, 10-substrate, 20-doped polarization layer, 30-two-dimensional material layer, 40-nitride film layer. DETAILED DESCRIPTION

[0032] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0033] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, specific embodiments of the present application are described in detail below with reference to the accompanying drawings. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the purpose of description, only the parts related to the present application are shown in the drawings, rather than all the structures. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0034] The terms "comprising" and "having" and any variations thereof herein are intended to cover a non-exclusive inclusion. For example, a process, method, system, product or apparatus that comprises a list of steps or units is not limited to the listed steps or units, but can optionally further include other steps or units not listed or can optionally further include other steps or units inherent to such processes, methods, products or apparatus.

[0035] In this document, reference to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that any of the embodiments described herein can be combined with any of the other embodiments unless specifically noted otherwise.

[0036] Figure 1 is a schematic flow chart of a nitride film according to an embodiment of the present application, Figure 2 is a graph of the polarization intensity of an AlN primitive cell versus u value, Figure 3 is a graph of the interface binding energy of a single-layer graphene / AlN heterojunction structure versus u value, Figure 4 is a graph of the graphene charge variation of a single-layer graphene / AlN heterojunction structure versus u value, Figure 5 is a schematic structural diagram of a nitride film according to an embodiment of the present application, Figure 6 is an Al 1-x Sc x N hysteresis loops at different Sc components.

[0037] It should be noted that in the analysis of the polarity strength of the substrate 10, the substrate 10 made of AlN material is taken as an example for analysis. Based on the AlN unit cell, the bond length in the C-axis direction is determined to be uc, the length of the unit cell c-axis is c, and the ratio of the two is u. u < 0.382 is metal polarity, and u > 0.382 is nitrogen polarity. The polarization strength is caused by the offset of the positive and negative charge centers in the unit cell. By moving the atomic positions, AlN units with different u values ​​are established, and they are divided into Al polarity and N polarity according to the polarization direction, and their polarization strengths are calculated accordingly. By simulating and optimizing the heterojunction structure of single-layer graphene / AlN with different polarization strengths, the interface binding energy between single-layer graphene and AlN is calculated, and the Bader charge is calculated at the same time, and the change in graphene charge after the interaction is obtained.

[0038] like Figures 2 to 4 As shown in Figure 2, as the u value changes, the trends of polarization intensity, heterojunction interface binding energy, and graphene charge change are basically consistent. Figure 2 It can be seen that as the u value increases, the polarization intensity first increases and then weakens when the metal polarity is high, and the turning point is at u=0.4, that is, when u>0.4, it is nitrogen polarity, and the polarity intensity continues to increase. Figure 3 and Figure 4 It can be seen that the interfacial binding energy between the monolayer graphene and substrate 10 and the change in graphene charge also increase first and then decrease at metal polarity, while continuing to increase at nitrogen polarity. This indicates that as the polarization strength increases, the interaction between substrate 10 and graphene strengthens, and the charge transferred from substrate 10 to graphene increases, indicating that stronger polarization strength is more conducive to remote epitaxy.

[0039] like Figure 1 As shown, the present invention provides a remote epitaxial growth method for a nitride film 100 based on a polarization effect, comprising:

[0040] Step S100: growing Al on the pre-treated substrate 10 1-x M x N-doped polarization layer 20 (refer to Figure 5 ), x is any value in the range of 0.15-0.45, and the element M is any one of Sc, Y, La, Nd, Gd, Dy, Er, Yb, and Lu;

[0041] Step S200: In Al 1-x M x A platinum electrode layer with a thickness of 50 nm to 100 nm is prepared on the surface of the N-doped polarization layer 20, and a current density of 10 mA / cm is applied to the platinum electrode layer. 2 -30mA / cm 2 The electric field is any value between -10MV / cm and 10MV / cm, so that the electric field acts on Al 1-x M xThe N-doped polarization layer 20 regulates the ferroelectric polarization effect and adjusts the Al 1-x M x The polarization intensity of the N-doped polarization layer 20 is 0.1 μC / cm 2 -250μC / cm 2 Any value in

[0042] Step S300: Etching the platinum electrode layer to expose the polarized Al 1-x M x N-doped polarization layer 20;

[0043] Step S400: Al in a polarized state 1-x M x The surface of the N-doped polarization layer 20 is sequentially grown with a two-dimensional material layer 30 and a nitride film layer 40 to prepare a nitride film 100. The growth temperature of the nitride film 40 is any value between 600°C and 1200°C. Here, the substrate 10 and the Al 1-x M x The N-doped polarization layer 20 forms a composite substrate.

[0044] In the method for preparing the nitride film 100 in this embodiment, firstly, Al with ferroelectric polarization effect is grown on the pre-treated substrate 10. 1-x M x N-doped polarization layer 20, then Al 1-x M x A platinum electrode layer is prepared on the surface of the N-doped polarization layer 20, and an electric field is applied to the platinum electrode layer to control the Al 1-x M x The polarization strength of the N-doped polarization layer 20 is then removed, and the platinum electrode layer is exposed again. 1-x M x The surface of the N-doped polarization layer 20 is sequentially grown with a two-dimensional material layer 30 and a nitride film layer 40, thereby preparing a nitride film 100. Here, the composition x of the doping element can be 0.15, 0.2, 0.25, 0.3, 0.35, 0.4 or 0.45, or any other value between 0.15 and 0.45. 1-x M x The polarization strength of the N-doped polarization layer 20 may be 0.1 μC / cm 2 , 1.0μC / cm 2 、10μC / cm 2 , 50μC / cm 2 、100μC / cm 2 、150μC / cm 2 , 200μC / cm 2 or 250μC / cm 2, or 0.1μC / cm 2 -250μC / cm 2 The growth temperature of the nitride film 100 is 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C or 1200°C, or any other value between 600°C and 1200°C.

[0045] In this embodiment, Al 1-x M x The doping element M of the N-doped polarization layer 20 can be any one of Sc, Y, La, Nd, Gd, Dy, Er, Yb, and Lu. When the composition of different doping elements M is within the above range, Al 1-x M x The piezoelectric material of the N-doped polarization layer 20 also has a ferroelectric polarization effect. That is, when the doping element M is Sc, x is any value between 0.22 and 0.43; when the doping element M is Y, x is any value between 0.20 and 0.35; when the doping element M is La, x is any value between 0.15 and 0.25; when the doping element M is Nd, x is any value between 0.18 and 0.3; when the doping element M is Gd, x is any value between 0.20 and 0.35; when the doping element M is Dy, x is any value between 0.22 and 0.38; when the doping element M is Er, x is any value between 0.25 and 0.4; when the doping element M is Yb, x is any value between 0.28 and 0.42; and when the doping element M is Lu, x is any value between 0.30 and 0.45.

[0046] In this embodiment, Al 1-x M x The N-doped polarization layer is used as the polarization substrate, and the Al 1-x M x The piezoelectric coefficient d of aluminum nitride material 33 , and then to the Al with ferroelectric polarization effect 1-x M x The platinum electrode layer on the surface of the N-doped polarization layer 20 applies a certain current density and an external electric field to regulate the Al 1-x M x The ferroelectric polarization effect of the N-doped polarization layer 20 is achieved by adjusting the Al 1-x M xThe center offset of positive and negative ions in the N-doped polarization layer 20 generates a larger polarization electric field to regulate the polarization intensity of the ferroelectric polarization effect, thereby enhancing the overall polarity of the composite substrate, so that the polarity of the composite substrate penetrates the two-dimensional material layer 30 and acts on the epitaxial growth process of the nitride film 100, avoiding the crystal quality problem caused by the two-dimensional material layer 30 weakening the polarity of the substrate 10, thereby facilitating the acquisition of low stress, low defect density, and strippable high-quality nitride film 100.

[0047] In this embodiment, the thickness of the platinum electrode layer can be 50nm, 60nm, 70nm, 80nm, 90nm or 100nm, or any other value between 50nm and 100nm, and the current density can be 10mA / cm 2 , 15mA / cm 2 , 20mA / cm 2 , 25mA / cm 2 or 30mA / cm 2 , or 10mA / cm 2 -30mA / cm 2 The applied electric field can be any other value in the range of -10MV / cm, -5MV / cm, -1MV / cm, 1MV / cm, 5MV / cm or 10MV / cm, or any other value in the range of -10MV / cm to 10MV / cm. That is, by setting the thickness of the platinum electrode layer, the current density and the applied electric field within the above range, the ferroelectric polarization can be effectively controlled while facilitating the subsequent etching process to remove the platinum electrode layer. The current density of the electric field and the setting of the applied electric field can work synergistically with the thickness of the platinum electrode layer to control the Al 1-x M x The ferroelectric polarization effect of the N-doped polarization layer 20 makes the Al 1-x M x The polarization intensity of the N-doped polarization layer 20 is 0.1 μC / cm 2 -250μC / cm 2 Any value in .

[0048] In a further embodiment, the step of etching the platinum electrode layer further includes:

[0049] The platinum electrode layer is removed by wet etching, and the wet etching solution includes potassium iodide (KI) with a concentration of any value between 0.5 mol / L and 1.0 mol / L and iodine (I2) with a concentration of any value between 0.05 mol / L and 0.1 mol / L. Here, the concentration of potassium iodide in the etchant for wet etching the platinum electrode layer can be 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L or 1.0 mol / L, or any other value between 0.5 mol / L and 1.0 mol / L, and the concentration of iodine can be 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L or 0.1 mol / L, or any other value between 0.05 mol / L and 0.1 mol / L.

[0050] In this embodiment, by using wet etching to remove the platinum electrode layer, and setting the concentrations of potassium iodide and iodine in the etching solution used for etching the platinum electrode layer within the above range, the KI / I2 etching solution has a high etching selectivity for metal platinum, which can ensure that the platinum electrode layer is etched rather than Al. 1-x M x The N-doped polarization layer 20 is damaged, and the complex reaction formed by KI / I2 controls the etching rate to be moderate, which can avoid excessive etching caused by excessive concentration and damage to the underlying Al layer. 1-x M x The N-doped polarization layer 20 may have an N-doped polarization layer 20, or the concentration may be too low, resulting in incomplete etching or residual platinum electrode, thereby preventing the subsequent polarization performance from being affected.

[0051] In this embodiment, the etching solution within the above concentration range can form a stable and uniform I3 - The complex is beneficial for achieving consistent etching of the platinum electrode layer on a large surface area, avoiding adverse effects such as edge residue and surface roughness after etching, and preventing the subsequent deposition quality of the two-dimensional material layer 30 from being affected.

[0052] In this embodiment, the pretreatment method of the substrate 10 includes chemical cleaning, ultrasonic cleaning, surface activation, standard RCA cleaning, mechanical polishing or electrolytic polishing to remove surface contamination and oxide layer, avoid interface reaction and defect generation during epitaxial growth, enhance nucleation consistency and crystallization quality, improve the stability and reliability of the heterostructure, and enhance the polarization field coupling capability.

[0053] In a further embodiment, the wet etching time is any value between 30s and 90s, that is, during the etching process of the platinum electrode layer, the wet etching time can be 30s, 40s, 50s, 60s, 70s, 80s or 90s, or any other value between 30s and 90s. In this embodiment, in a KI / I2 solution with a moderate concentration, the etching time within the above range is sufficient to completely remove the platinum electrode layer with a thickness of 50nm-100nm, avoid surface conductivity, interface reaction or polarization disturbance caused by residual electrode, and ensure that the polarization strength is stably retained at Al 1-x M x N doped polarization layer 20, and can also avoid etching time too long resulting in etching solution and Al 1-x M x The risk of chemical reaction or diffusion between the materials of the N-doped polarization layer 20 increases, thereby effectively preventing the Al 1-x M x The N-doped polarization layer 20 causes corrosion or stress damage, increasing the Al 1-x M x The structural integrity of the N-doped polarization layer 20.

[0054] In a further embodiment, the material of the substrate 10 is any one of sapphire, silicon, silicon carbide, diamond, aluminum nitride, gallium nitride or molybdenum. In this embodiment, since the Al 1-x M x The polarization strength of the N-doped polarization layer 20 is used to actively control the polarity of the heterojunction interface, making the polarization control no longer dependent on the crystal polarity or spontaneous polarization properties of the underlying substrate 10. This allows for epitaxial growth of high-quality nitride thin films 100 on non-polar or low-polarity substrates 10, significantly reducing dependence on the polarity of the underlying substrate 10. In other words, even when using non-polar or weakly polar silicon or sapphire as the substrate 10, high-quality, directional epitaxial growth can be achieved through polarization control, thus breaking the reliance on high-polarity substrates 10 in traditional epitaxial growth and significantly expanding the types and sources of optional substrates 10.

[0055] In a further embodiment, Al 1-x M x The growth method of the N-doped polarization layer 20 is any one of metal organic chemical vapor deposition, molecular beam epitaxy or magnetron sputtering. In this embodiment, by adopting a variety of highly controllable growth techniques, the uniform doping degree and crystal orientation of the doping elements in the AlN lattice can be effectively controlled to ensure the uniformity of the AlN lattice. 1-x M x The crystal quality and thickness accuracy of the N-doped polarization layer 20 can improve the stability and adjustable range of the polarization response. 1-x Mx The N-doped polarization layer 20 is compatible with multiple growth methods and can coordinate with the key steps of electrode deposition, electric field regulation, and polarization strength solidification, thereby improving the overall process integration and the stability of the epitaxial growth of the nitride film 100.

[0056] In a further embodiment, Al 1-x M x The growth temperature of the N-doped polarization layer 20 is any value between 450°C and 550°C, the growth pressure is any value between 0.5Pa and 2.0Pa, and the RF power is any value between 100W and 200W, i.e., Al 1-x M x The growth temperature during the preparation of the N-doped polarization layer 20 can be 450°C, 470°C, 490°C, 500°C, 510°C, 530°C or 550°C, or any other value between 450°C and 550°C; the growth pressure can be 0.5Pa, 1.0Pa, 1.5Pa or 2.0Pa, or any other value between 0.5Pa and 2.0Pa; the RF power can be 100W, 120W, 140W, 160W, 180W or 200W, or any other value between 100W and 200W. In this embodiment, by increasing the Al 1-x M x The growth temperature, growth pressure and RF power of the N-doped polarization layer 20 are set within the above ranges. The coordinated regulation of the growth temperature, growth pressure and RF power is conducive to the uniform distribution of the doping elements in the AlN lattice, reducing stress accumulation, reducing the probability of dislocation density and vacancy defect formation, and preparing AlN with uniform thickness and adjustable polarization strength. 1-x M x N-doped polarization layer 20 .

[0057] In this embodiment, Al 1-x M x The growth temperature of the N-doped polarization layer 20 is set at any value between 450°C and 550°C, which helps to enhance the surface mobility of the reactants, avoid lattice defects or impurity aggregation caused by overheating, and ensure the uniform distribution of doping elements in the AlN lattice, thereby improving the Al 1-x M x The crystal integrity of the N-doped polarization layer 20 .

[0058] In this embodiment, Al 1-x M x The growth pressure of the N-doped polarization layer 20 is any value between 0.5Pa and 2.0Pa, which can effectively control the reactant flux and plasma intensity, reduce the stress accumulation in the film, reduce the probability of forming defects such as dislocations and vacancies, and improve the Al 1-x M xThe structural stability of the N-doped polarization layer 20 is improved.

[0059] In this embodiment, Al 1-x M x The RF power of the N-doped polarization layer 20 is set to any value between 100W and 200W, which can ensure a stable deposition rate and moderate ion bombardment intensity, thereby achieving high polarization intensity while avoiding damage to the lattice structure or causing surface roughness.

[0060] In a further embodiment, the two-dimensional material layer 30 is made of any one of graphene, hexagonal boron nitride, or transition metal sulfide. In this embodiment, the two-dimensional material has an atomically flat surface and a dangling bond-free structure, which can effectively shield the defect transmission caused by the lattice mismatch on the surface of the substrate 10, reducing the adverse effects of lattice mismatch on the crystal quality of the nitride film 100 during heteroepitaxial growth, thereby promoting the remote epitaxial growth of high-quality, low-defect density nitride film 100. By selecting the appropriate material, the ability to transmit an applied electric field or polarization field can be controlled, thereby enhancing the influence of polarization control on the nucleation and growth behavior of the upper nitride film 100.

[0061] In this embodiment, the two-dimensional materials exhibit excellent thermal stability and chemical inertness, making them suitable for high-temperature epitaxial growth environments. Furthermore, they exhibit good peelability and interface engineering feasibility in subsequent device structures, facilitating subsequent applications such as thin film transfer and flexible electronics.

[0062] In a further embodiment, the two-dimensional material layer 30 is grown by chemical vapor deposition (CVD) or molecular beam epitaxy (MBE). In this embodiment, by depositing the two-dimensional material layer 30 using CVD or MBE, not only can its crystal quality and uniformity be guaranteed, but the accuracy and controllability of the interface engineering can also be improved, thereby enhancing the feasibility and process flexibility of the present invention in constructing a high-quality nitride film 100 remote epitaxial structure.

[0063] In a further embodiment, the thickness of the two-dimensional material layer 30 is any value between 0.34 nm and 1 nm, that is, the thickness of the two-dimensional material layer 30 can be 0.34 nm, 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, or 1 nm, or any other value between 0.34 nm and 1 nm. In this embodiment, effective penetration of the polarization electric field, control of the interface stress, preservation of the two-dimensional material properties, and structural exfoliation capability are all taken into account, thereby further improving the overall performance of the remote epitaxial structure of the high-quality nitride film 100 in this embodiment.

[0064] The present application will be further described in detail below with reference to specific embodiments.

[0065] In some embodiments, in the remote epitaxial growth method of the nitride film 100, Al is first deposited on a substrate 10 made of sapphire, silicon, silicon carbide, diamond, aluminum nitride, gallium nitride or molybdenum. 1-x M x N-doped polarization layer 20, the composition x of doping element M is any value in the range of 0.15-0.45, and the doping element M is any one of Sc, Y, La, Nd, Gd, Dy, Er, Yb, and Lu. 1-x M x A platinum electrode layer with a thickness of 50 nm to 100 nm is prepared on the surface of the N-doped polarization layer 20, and a current density of 10 mA / cm is applied to the platinum electrode layer. 2 -30mA / cm 2 The applied electric field is any value between -10MV / cm and 10MV / cm, so that the applied electric field acts on Al 1-x M x The N-doped polarization layer 20 regulates the ferroelectric polarization effect and adjusts the Al 1-x M x The polarization intensity of the N-doped polarization layer 20 is 0.1 μC / cm 2 -250μC / cm 2 The platinum electrode layer is then removed by wet etching. The wet etching solution includes potassium iodide with a concentration of 0.5 mol / L-1.0 mol / L and iodine with a concentration of 0.05 mol / L-0.1 mol / L. The etching time is any value from 30 s to 90 s. Then, the Al2O3 exposed after the platinum electrode layer is removed is removed. 1-x M x A two-dimensional material layer 30 and a nitride film layer 40 are sequentially deposited on the surface of the N-doped polarization layer 20 to prepare a nitride thin film 100 .

[0066] Example 1

[0067] In the remote epitaxial preparation method of the nitride film 100, a 500nm thick Al2O3 film is grown on the sapphire substrate 10 using MOCVD technology. 0.76 Sc 0.27 N-doped polarization layer 20, on Al 0.76 Sc 0.27 The surface of the N-doped polarization layer 20 is plated with a platinum electrode layer with a thickness of 50 nm, and an external electric field strength of -7 MV / cm and a current density of 25 mA / cm are applied. 2 , Al 0.76 Sc 0.27 The polarization intensity of the N-doped polarization layer 20 is about -175 μC / cm 2 , then use wet etching to remove Al 0.76 Sc 0.27A platinum electrode layer is formed on the surface of the N-doped polarization layer 20, and then a 0.34 nm graphene layer is directly grown in situ on the surface. Finally, a 2 μm GaN film is directly epitaxially grown at 1050°C in one step.

[0068] Example 2

[0069] Using a silicon carbide substrate 10, an Al2O3 layer with a thickness of 100 nm is grown on the substrate 10 using MBE technology. 0.7 Sc 0.32 N-doped polarization layer 20, on Al 0.7 Sc 0.32 The surface of the N-doped polarization layer 20 is plated with a platinum electrode layer with a thickness of 50 nm, and an external electric field strength of -6 MV / cm and a current density of 25 mA / cm are applied. 2 , at this time Al 0.7 Sc 0.32 The polarization intensity of the N-doped polarization layer 20 is about -150 μC / cm 2 , then use wet etching to remove Al 0.7 Sc 0.32 A platinum electrode layer is formed on the surface of the N-doped polarization layer 20, and then a single-layer graphene with a thickness of 0.34 nm is transferred on the surface. Finally, a 2 μm GaN film is directly grown in one step at 1050°C.

[0070] Example 3

[0071] Using gallium nitride as substrate 10, MBE technology is used to epitaxially grow 200nm of Al on the substrate 10. 0.76 Sc 0.27 N-doped polarization layer 20, on Al 0.76 Sc 0.27 After the surface of the N-doped polarization layer 20 is plated with a platinum electrode layer having a thickness of 50 nm, an external electric field strength of 7 MV / cm and a current density of 25 mA / cm is applied. 2 , at this time Al 0.76 Sc 0.27 The polarization strength of the N-doped polarization layer 20 is about 155 μC / cm 2 , then use wet etching to remove Al 0.76 Sc 0.27 A platinum electrode layer is formed on the surface of the N-doped polarization layer 20, and then a 1 nm thick amorphous boron nitride is directly grown on the surface using MBE technology. Finally, a 1 μm polarity-reversed AlN film is directly epitaxially grown in one step at 1100°C.

[0072] Comparative Example 1

[0073] The only difference between the comparative example and Example 1 is that the platinum electrode layer is not prepared and no external electric field and current are applied.

[0074] Comparative Example 2

[0075] The only difference between Comparative Example 2 and Example 2 is that AlN is epitaxially grown on the substrate 10 as the doped polarization layer 20 .

[0076] Comparative Example 3

[0077] The only difference between Comparative Example 3 and Example 3 is that AlN is directly epitaxially grown on the substrate 10 as the doped polarization layer 20, and no platinum electrode layer is prepared and no external electric field or current is applied.

[0078] The dislocation density of the nitride film layer 40 in the nitride thin films 100 prepared in Examples 1-3 and Comparative Examples 1-3 was tested, and the test results shown in Table 1 were obtained.

[0079]

[0080] As shown in Table 1, under the same preparation process conditions, the dislocation density of Example 1 and Example 2 is significantly lower than that of the corresponding Comparative Example 1 and Comparative Example 2, indicating that Al 1-x M x The N-doped polarization layer 20 cooperates with the platinum electrode layer and the external electric field and current density to improve the Al 1-x M x The polarization strength of the N-doped polarization layer 20 significantly reduces the dislocation density of the nitride film 100 grown by remote epitaxy and based on the polarization effect, significantly improving the growth quality of the nitride film 100 grown by remote epitaxy. In Comparative Example 3, however, only AlN was used as the doped polarization layer 20. The polarity of the AlN-doped polarization layer 20 was unable to penetrate 1 nm of amorphous boron nitride, indicating that AlN as the doped polarization layer 20 lacks a ferroelectric polarization effect and has extremely low polarization strength, making it unsuitable for use as a polarization layer in the remote epitaxial growth of the nitride film 100.

[0081] like Figure 6 As shown, curve a, curve b and curve c are respectively the Al with Sc component x of 0.27, 0.32 and 0.36 1-x Sc x N hysteresis loop. Figure 6 It can be seen that curves a, b and c are standard rectangular loops, indicating that the Sc component has a ferroelectric polarization effect within the above range, and can realize the polarity control of the doped polarization layer 20 under the control of the electric field. In addition, with the increase of the Sc element doping component, the Al 1-x Sc x The coercive electric field (Ec) and remnant polarization (Pr) of N gradually decrease, further indicating that the Sc component can achieve polarization regulation within the above range.

[0082] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The above-described embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that a person skilled in the art would be able to make numerous modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A remote epitaxial growth method for nitride thin films based on polarization effect, characterized in that: include: Growth of Al on pretreated substrates 1-x M x N-doped polarization layer, x is any value in the range of 0.15-0.45, and the element M is any one of Sc, Y, La, Nd, Gd, Dy, Er, Yb, and Lu; In the Al 1-x M x A platinum electrode layer with a thickness of 50 nm to 100 nm is prepared on the surface of the N-doped polarization layer, and a current density of 10 mA / cm is applied to the platinum electrode layer. 2 -30mA / cm 2 The electric field is any value in the range of -10MV / cm to 10MV / cm, so that the electric field acts on the Al 1-x M x The N-doped polarization layer regulates the ferroelectric polarization effect and adjusts the Al 1-x M x The polarization strength of the N-doped polarization layer is 0.1 μC / cm 2 -250μC / cm 2 Any value in The platinum electrode layer is etched to expose the Al in a polarized state. 1-x M x N-doped polarization layer; In the polarized state of the Al 1-x M x A two-dimensional material layer and a nitride film layer are sequentially grown on the surface of the N-doped polarization layer to prepare the nitride thin film, wherein the growth temperature of the nitride film layer is any value between 600° C. and 1200° C.; The step of etching the platinum electrode layer further comprises: Removing the platinum electrode layer by wet etching, wherein the wet etching solution includes potassium iodide with a concentration of any value between 0.5 mol / L and 1.0 mol / L and iodine with a concentration of any value between 0.05 mol / L and 0.1 mol / L; The etching time of the wet etching is any value between 30s and 90s.

2. The remote epitaxial preparation method according to claim 1, characterized in that: The substrate is made of any one of sapphire, silicon, silicon carbide, diamond, aluminum nitride, gallium nitride or molybdenum.

3. The remote epitaxial preparation method according to claim 2, characterized in that: The Al 1-x M x The N-doped polarization layer is grown by any one of metal organic chemical vapor deposition, molecular beam epitaxy or magnetron sputtering.

4. The remote epitaxial preparation method according to claim 3, characterized in that: The Al 1-x M x The growth temperature of the N-doped polarization layer is any value between 450°C and 550°C, the growth pressure is any value between 0.5Pa and 2.0Pa, and the radio frequency power is any value between 100W and 200W.

5. The remote epitaxial preparation method according to claim 4, characterized in that: The material of the two-dimensional material layer is any one of graphene, hexagonal boron nitride or transition metal sulfide.

6. The remote epitaxial preparation method according to claim 5, characterized in that: The two-dimensional material layer is grown by chemical vapor deposition or molecular beam epitaxy.

7. The remote epitaxial preparation method according to claim 1, characterized in that: The thickness of the two-dimensional material layer is any value between 0.34 nm and 1 nm.

Images