A method for changing the interfacial thermal characteristics of a gallium nitride layer by changing the twist angle

Abstract

This invention provides a method for predicting changes in interfacial thermal properties by altering the interlayer torsion angle of gallium nitride (GaN) layers, belonging to the field of microscale thermal transport technology. The method includes: using a GaN layer of a predetermined size as a substrate, and employing another, larger GaN layer aligned with the center of the substrate as an epitaxial layer on top of the substrate, establishing an initial molecular dynamics model; rotating the epitaxial layer according to a predetermined torsion angle, and trimming the epitaxial layer with the substrate size as a reference to obtain a computational model of the same size as the substrate interface, thus forming a GaN / GaN thermal conduction system; using molecular dynamics simulation to perform stepwise relaxation on the GaN / GaN thermal conduction system, and obtaining the energy and interface temperature during the steady-state simulation after the system reaches equilibrium; and obtaining the interfacial thermal resistance under different torsion angles based on the energy changes and interface temperature differences at different torsion angles. This invention reveals the influence of different interlayer torsion angles on GaN / GaN interlayer thermal conduction.

Description

Technical Field

[0001] This invention relates to the field of microscale thermal transport technology, and in particular to a method for predicting changes in interfacial thermal properties by altering the interlayer torsion angle of gallium nitride. Background Technology

[0002] Gallium nitride (GaN), as a material for high-power electronic devices, is widely used in high-mobility transistors, metal-oxide-semiconductor field-effect transistors, and other applications. The interfacial thermal resistance between GaN and its substrate is a bottleneck for heat dissipation, and this bottleneck should be optimally reduced to fully utilize the substrate's high thermal conductivity. To improve the heat dissipation efficiency of GaN-based high-power devices, researchers have implemented numerous strategies for thermal management optimization, which can be broadly categorized into two types. The first type of optimization involves using substrate materials with high thermal conductivity to enhance the overall thermal transfer efficiency of the structure. However, despite using substrate materials with high thermal conductivity, there is a mismatch between the lattice structure and the coefficient of thermal expansion (CTE) of GaN. This leads to high defect density in the GaN crystal structure during growth due to stress accumulation, causing a decrease in thermal conductivity and often limiting effective heat transfer. The second type of research focuses on improving the thermal conductivity of GaN itself. More importantly, it addresses GaN-GaN homoelectrode thermal conduction, as the ideal solution for obtaining high-quality GaN epitaxial layers is homoelectrode epitaxy, i.e., growing GaN layers on bulk GaN substrates. The main advantage of GaN grown epitaxially is its low dislocation density (10). 4 -10 6 / cm 2 ) and the lattice and thermal expansion coefficient that are inherently matched with the grown GaN layer.

[0003] During homoepitaxial growth, alignment errors in different GaN layers lead to a certain degree of torsion angle deviation between them. This phenomenon affects the thermal conduction between GaN / GaN layers. Research on this phenomenon is relatively lacking, and the mechanism by which the interface torsion angle affects thermal conduction is unclear. Summary of the Invention

[0004] This invention provides a method for predicting changes in interface thermal properties by altering the interlayer torsion angle of gallium nitride, thereby addressing the deficiencies in the prior art.

[0005] This invention provides a method for predicting changes in interface thermal properties by altering the interlayer torsion angle of gallium nitride (GaN), comprising: using a GaN of a preset size as a substrate, and employing another larger GaN layer aligned with the center of the substrate as an epitaxial layer above the substrate, establishing an initial state molecular dynamics model; rotating the epitaxial layer according to a preset torsion angle, and cutting the epitaxial layer with the substrate size as a reference to obtain a computational model of the same size as the substrate interface, thereby constituting a GaN / GaN thermal conduction system; using molecular dynamics simulation to perform stepwise relaxation on the GaN / GaN thermal conduction system, and obtaining the energy and interface temperature during the steady-state simulation process after the system reaches equilibrium; and obtaining the interface thermal resistance under different torsion angles based on the energy changes and interface temperature differences at different torsion angles of contact.

[0006] According to the method for predicting changes in interfacial thermal properties by altering the interlayer torsion angle of gallium nitride provided by the present invention, the substrate of the initial state molecular dynamics model consists of m1×n1×h unit cells, and the epitaxial layer consists of m2×n2×h unit cells, and satisfies the following quantitative relationship. , Where, M1 = m1 × a N1 = n1 × b, H = h × c a b and c are the lattice lengths of gallium nitride unit cells in the X, Y, and Z directions, respectively.

[0007] According to the method for predicting the change of interface thermal properties by changing the interlayer torsion angle of gallium nitride provided by the present invention, the initial state molecular dynamics model is divided into eight functional layers from top to bottom according to different functions: fixed layer, heat source layer, Newton layer, epitaxial layer interface, substrate layer interface, Newton layer, heat sink and fixed layer.

[0008] The method for predicting interface thermal property changes by changing the interlayer torsion angle of gallium nitride according to the present invention involves rotating the epitaxial layer according to a preset torsion angle, and cutting the epitaxial layer with the substrate size as a reference to obtain a calculation model of the same size as the substrate interface. The method includes: rotating the epitaxial layer in the range of 0° to 60° at 5° intervals; and cutting the epitaxial layer with the same size as the substrate interface with reference to the cross-sectional size and boundary of the gallium nitride substrate to form a calculation model of the same size as the substrate interface.

[0009] The method for predicting interface thermal property changes by altering the interlayer torsion angle of gallium nitride (GaN) provided by this invention utilizes molecular dynamics simulations to perform stepwise relaxation on a GaN / GaN thermal conduction system. After the system reaches equilibrium, the energy and interface temperature during the steady-state simulation are obtained. This includes: optimizing the atomic system energy to a minimum using a conjugate gradient algorithm; setting the initial temperature T0 of the system in an isothermal-isobaric ensemble (NPT), maintaining constant atomic number, volume, and temperature for relaxation to eliminate structural stress, thereby achieving thermodynamic equilibrium in the system's volume and pressure; fixing the system volume in a canonical ensemble (NVT) to stabilize the system temperature at a target value; and controlling the temperatures of the heat source and heat sink in a microcanonical ensemble (NVE) as follows: T h =T0×(1+δ)T s =T0×(1-δ;where T h T represents the temperature of the heat source. s δ represents the heat sink temperature and the normalized temperature difference factor. The steady-state heat conduction under different torsional angle contact states is analyzed by converting internal potential energy into kinetic energy. The system temperature is controlled by a Langevin thermostat, and energy and interface temperature are obtained during the steady-state heat transfer process.

[0010] The method for predicting interface thermal property changes by changing the interlayer torsion angle of gallium nitride according to the present invention further includes: when the gallium nitride / gallium nitride system relaxes in the NPT ensemble, setting non-periodic boundary conditions in the X-axis and Y-axis directions and setting periodic boundary conditions in the Z-axis direction; and during the relaxation of the NVT ensemble and the steady-state heat transfer process of the NVE ensemble, setting non-periodic boundary conditions in the X-axis and Y-axis directions and setting fixed boundary conditions in the Z-axis direction.

[0011] The method for predicting changes in interface thermal properties by altering the interlayer torsion angle of gallium nitride provided by the present invention further includes: the interaction between all nitrogen atoms and gallium atoms in the substrate and epitaxial layer is described by the Tersoff potential.

[0012] The method for predicting interface thermal property changes by changing the interlayer torsion angle of gallium nitride according to the present invention obtains the interface thermal resistance under different torsion angles based on the energy change and interface temperature difference when in contact at different torsion angles, including: calculating the heat flux based on the energy change when in contact at different torsion angles; and calculating the interface thermal resistance based on the heat flux and interface temperature difference.

[0013] According to the method for predicting changes in interfacial thermal properties by altering the interlayer torsion angle of gallium nitride provided by the present invention, the heat flux is calculated based on the energy changes at different torsion angles. Specifically: ; in, q The magnitude of heat flux; This refers to the total energy released by the heat source during a steady-state heat transport process. denoted as , where is the total energy absorbed by the heat sink; A is the atomic contact area at the interface.

[0014] According to the method for predicting changes in interfacial thermal properties by altering the interlayer torsion angle of gallium nitride provided by the present invention, the interfacial thermal resistance is calculated based on the heat flux and the interfacial temperature difference, specifically as follows: ; in, The magnitude of the interfacial thermal resistance, This represents the temperature difference between the two ends of the interface.

[0015] The method for predicting changes in interface thermal properties by altering the interlayer torsion angle of gallium nitride provided by this invention has the following advantages compared with existing methods: (1) In view of the fact that the influence of alignment error on interface thermal properties during gallium nitride homoepitaxial process has not been solved, this invention proposes a controllable structural modeling and interface thermal property analysis method, and uses low-cost molecular dynamics technology to calculate the changes in the thermal properties of gallium nitride / gallium nitride interface when contacted at different torsion angles.

[0016] (2) This invention combines the quantum analysis of interface energy change and further elucidates the reason for the different interface thermal resistance under different torsion angles on the basic mechanism. This is very helpful for the testing and analysis of gallium nitride devices when using multi-physics fields in practical applications. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the method for predicting changes in interfacial thermal properties by altering the interlayer torsion angle of gallium nitride provided by the present invention. Figure 2 This is a schematic diagram of the initial state molecular dynamics model provided by the present invention; Figure 3 This is a schematic diagram of the process of twisting and cutting the epitaxial layer provided by the present invention; Figure 4 This is a structural diagram of the interfacial atomic arrangement under different torsion angles provided by the present invention; Figure 5 This is a schematic diagram of energy acquisition and interface temperature during steady-state heat transfer provided by the present invention; Figure 6This is a schematic diagram showing the changes in total accumulated energy and the changes in the temperature difference at the gallium nitride / gallium nitride interface under different torsion angles, as provided by the present invention. Figure 7 This is a schematic diagram illustrating the changes in heat flux and the changes in thermal resistance at the gallium nitride / gallium nitride interface under different torsion angles provided by the present invention. Figure 8 This is a phonon spectrum curve of interface atoms under different torsion angles provided by the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] It should be noted that, in the description of the embodiments of the present invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0021] The following is combined with Figures 1-8 This invention describes a method for predicting changes in interface thermal properties by altering the interlayer torsion angle of gallium nitride, as provided in embodiments of the present invention.

[0022] Figure 1 This is a flowchart illustrating the method for predicting changes in interfacial thermal properties by altering the interlayer torsion angle of gallium nitride provided by the present invention. Figure 1 As shown, including but not limited to the following steps: Step 101: Using a gallium nitride of a preset size as a substrate, and using another gallium nitride of a larger size aligned with the center of the substrate as an epitaxial layer on top of the substrate, establish an initial state molecular dynamics model.

[0023] Specifically, taking a piece of size as A single-cell gallium nitride layer serves as the substrate; another gallium nitride layer, larger than the substrate, serves as the epitaxial layer, which is composed of… Composed of (unit cells), the orthogonalized gallium nitride unit cells have lattice lengths corresponding to the X, Y, and Z directions, respectively. a , b and c Then the lengths of the substrate in the X, Y, and Z directions are , and The lengths of the epitaxial layer in the X, Y, and Z directions are , and In the established model, the substrate and epitaxial layer have equal heights and are center-aligned. It is also necessary to ensure... and .

[0024] Step 102: Rotate the epitaxial layer according to a preset twist angle, and cut the epitaxial layer with the substrate size as a reference to obtain a computational model of the same size as the substrate interface, thereby forming a gallium nitride / gallium nitride thermal conduction system.

[0025] Specifically, the epitaxial layer is rotated at 5° intervals within a range of 0° to 60°. Then, referring to the cross-sectional size and boundary of the gallium nitride substrate, the epitaxial layer is cut to obtain an epitaxial layer with the same size as the substrate interface, forming a gallium nitride / gallium nitride thermal conduction system.

[0026] Step 103: Use molecular dynamics simulation to perform stepwise relaxation on the gallium nitride / gallium nitride thermal conduction system. After the system reaches equilibrium, obtain the energy and interface temperature during the steady-state simulation process.

[0027] Specifically, the system simulation first uses the conjugate gradient algorithm to optimize the energy of the atomic system to a minimum. Then, in an isothermal-isobaric ensemble (NPT), the initial temperature of the system is set to T0, and relaxation is performed while maintaining constant atomic number, volume, and temperature to eliminate structural stress, thereby achieving thermodynamic equilibrium in the system's volume and pressure. Further, in a canonical ensemble (NVT), the system volume is fixed to keep the system temperature stable at the target value. Finally, in a microcanonical ensemble (NVE), the temperatures of the heat source and heat sink are controlled to be T0 and T0, respectively. h =T0×(1+δ)T s =T0×(1-δ), where δ is the normalized temperature difference factor. The steady-state heat conduction under different torsional angle contact states is analyzed by the conversion of internal potential energy and kinetic energy. The system temperature is controlled by a Langevin thermostat, and energy and interface temperature are obtained during the steady-state heat transfer process.

[0028] Step 104: Obtain the interfacial thermal resistance under different torsion angles based on the energy change and interfacial temperature difference when in contact at different torsion angles.

[0029] Furthermore, in step 101, the modeling software used to establish the initial state molecular dynamics model can be Ovito or Lammps, and the established initial state molecular dynamics model is as follows: Figure 2 As shown, Figure 2 This is a schematic diagram of the initial state molecular dynamics model provided by the present invention.

[0030] Furthermore, in step 101, the initial state molecular dynamics model is divided into eight functional layers from top to bottom according to different functions: fixation layer, heat source layer, Newton layer, epitaxial layer interface, substrate layer interface, Newton layer, heat sink, and fixation layer.

[0031] Furthermore, in step 102, the substrate and the cut epitaxial layer in the system maintain the same 8 functional layers during heat conduction under different torsion angles.

[0032] Furthermore, in step 103, when the gallium nitride / gallium nitride system relaxes in the NPT ensemble, non-periodic boundary conditions are set in the X-axis and Y-axis directions, and periodic boundary conditions are set in the Z-axis direction. During the relaxation of the NVT ensemble and the steady-state heat transfer process of the NVE ensemble, non-periodic boundary conditions are set in the X-axis and Y-axis directions, and fixed boundary conditions are set in the Z-axis direction.

[0033] Furthermore, the interaction between all nitrogen and gallium atoms in the substrate and epitaxial layer of the system is achieved using the Tersoff interaction potential.

[0034] Furthermore, in step 104, the heat flux is calculated based on the energy change at different torsional angles in the system. The calculation relationship used is as follows:

[0035] in, q The heat flux is expressed in MW / m³. 2 ; The total energy released by the heat source during a steady-state heat transport process, expressed in eV; A is the total energy absorbed by the heat sink, in eV; A is the atomic contact area at the interface, in m². 2 .

[0036] Furthermore, in step 104, the interfacial thermal resistance is calculated based on the obtained heat flux and interfacial temperature difference. The calculation relationship used is as follows:

[0037] in: The temperature difference between the two ends of the interface is expressed in Kelvin (K).

[0038] Furthermore, based on the interface energy quantization, the fundamental mechanism of interface thermal resistance change is analyzed by deriving the interface phonon spectrum, and the phonon spectrum is calculated. The calculation relationships used are as follows:

[0039] in, It is the angular frequency of lattice vibrations during heat transfer. This represents the total steady-state heat transfer time. This is the velocity autocorrelation function, where <> indicates averaging. This represents the velocity vector of an atom at time t. This represents the velocity vector of an atom at the initial time (t=0).

[0040] In summary, this invention, combining molecular dynamics and quantum theory, proposes a method for predicting changes in interfacial thermal properties by altering the torsion angle between gallium nitride / gallium nitride layers. This method establishes a low-cost molecular dynamics model, calculates the interfacial thermal resistance at different torsion angles between gallium nitride / gallium nitride layers, and analyzes the reasons for the changes in interfacial thermal resistance from the perspective of energy quantization. To make the purpose, technical solution and advantages of this invention patent clearer, the invention will be further described in detail below with reference to the accompanying drawings and a complete embodiment.

[0041] 1. Establish an initial molecular dynamics model A gallium nitride (GaN) substrate with dimensions of 15×27×10 (unit cells) is used; another GaN layer, larger than the substrate, is used as the epitaxial layer, consisting of 24×42×10 (unit cells). The orthogonal GaN unit cells have lattice lengths corresponding to the X, Y, and Z directions, respectively. a= 5.5234 Å b= 3.1891 Å and c= 5.1923 Å, then the lengths of the substrate in the X, Y, and Z directions are... =82.851 Å, = 86.1057 Å and =51.923 Å, the length of the epitaxial layer in the X, Y and Z directions is =132.5616 Å, =133.9422 Å and =51.923 Å; the initial state model diagram is shown below. Figure 2 As shown, the model is divided into eight functional layers from top to bottom according to different functions: fixed layer, heat source layer, Newton layer, epitaxial layer interface, substrate layer interface, Newton layer, heat sink and fixed layer.

[0042] 2. Rotate by a specific angle to obtain the computational model. The epitaxial layer is rotated at 5° intervals within a range of 0° to 60°. Then, the epitaxial layer is cut according to the cross-sectional size and boundary of the gallium nitride substrate to obtain an epitaxial layer with the same size as the substrate interface. Figure 3 This is a schematic diagram of the process of twisting and cutting the epitaxial layer provided by the present invention, as shown in the figure. Figure 3 As shown, ① is a schematic diagram of the initial state, and ② is a schematic diagram of rotational clipping. In the figure, S1, S2, S3, and S4 are the reference planes for clipping the epitaxial layer. θ ③ represents the torsion angle, and ③ represents the final gallium nitride / gallium nitride thermal conductivity system model obtained by cutting. The epitaxial layer and the substrate have an interface of equal size; the relative position changes of the interface atoms when in contact at different torsion angles form, as shown in the figure. Figure 4 The interface structure shown is as follows: Figure 4 This is a structural diagram of the interfacial atomic arrangement under different torsion angles provided by the present invention.

[0043] 3. Run the molecular dynamics model In the Lammps software package, the interatomic interactions in the gallium nitride / gallium nitride system are expressed using the Tersoff potential. The conjugate gradient algorithm is used to optimize the energy of the atomic system to a minimum. Then, in an isothermal-isobaric ensemble (NPT), the initial temperature of the system is set to T0 = 330 K. Non-periodic boundary conditions are set in the X and Y axes, and periodic boundary conditions are set in the Z axis. Relaxation is performed while keeping the number of atoms, volume, and temperature constant to eliminate structural stress and bring the system to thermodynamic equilibrium in terms of volume and pressure. The system volume is further fixed in a canonical ensemble (NVT) to stabilize the system temperature at the target value. Finally, in a microcanonical ensemble (NVE), the normalized temperature difference factor is set to 0.1, and the temperatures of the heat source and heat sink are controlled to be T0 and T0, respectively. h =363 K, T s =297 K; Non-periodic boundary conditions are set in the X and Y axes, and fixed boundary conditions are set in the Z axis. The steady-state heat conduction process under different torsional angle contact states is analyzed by the conversion of internal potential energy and kinetic energy. The temperature is controlled by a Langevin thermostat. Figure 5 This is a schematic diagram of energy acquisition and interface temperature during steady-state heat transfer provided by the present invention. Figure 5 Figure (a) shows that at torsion angles of 0°, 30°, and 60°, the rates of energy release and absorption by the heat source and heat sink in the system differ significantly over time, with the energy absorption rate showing the order 0° > 60° > 30°. Figure 5 (b) shows the temperature changes in the system when the torsion angles are 0°, 30° and 60°. The results show that the temperature gradient does not change with the angle, and the temperature difference at the interface is 30°>60°>0°.

[0044] 4. Simulation Data Processing 4.1 Calculation of total accumulated energy and interface temperature difference under different torsion angles Figure 6 This is a schematic diagram illustrating the changes in total accumulated energy and the temperature difference at the gallium nitride / gallium nitride interface under different torsion angles, as provided by this invention; the total energy accumulated during steady-state simulation under different torsion angles is extracted, such as... Figure 6 As shown in part (a), the accumulated energy is minimal when the torsion angle is 30°; the interface temperature difference at different torsion angles is calculated based on the temperature gradient as follows: Figure 6 As shown in part (b), the interface temperature difference is the largest when the torsion angle is 30°.

[0045] 4.2 Calculation of heat flux and interfacial thermal resistance at different torsion angles Figure 7 This is a schematic diagram illustrating the changes in heat flux and the changes in the thermal resistance of the gallium nitride / gallium nitride interface under different torsion angles, as provided by the present invention.

[0046] The heat flux calculations for contact processes with different torsional angles yielded the following results: Figure 7 As shown in part (a) of the figure, the heat flux at the interface is minimum when the torsion angle is 30°.

[0047] Calculate the interfacial temperature difference between atoms in the interface layer when in contact with different torsion angles, such as... Figure 7 As shown in section (b) of the figure, the interfacial thermal resistance is the maximum when the torsion angle is 30°.

[0048] 4.3 Analysis of interfacial phonon spectra at different torsional angles The phonon spectra of interfacial atoms were analyzed when they were in contact at different torsional angles. Figure 8 This is a phonon spectrum curve of interface atoms at different torsion angles provided by the present invention, such as... Figure 8 As shown in the figure, when the torsion angle changes from 0° to 30°, the low-frequency peak of the PDOS curve gradually weakens and shifts to higher frequencies, resulting in a decrease in the interface heat transfer capability. When the torsion angle changes from 30° to 60°, the low-frequency peak of the PDOS curve becomes more significant and shifts to lower frequencies, thus enhancing the interface heat conduction capability.

[0049] In summary, the method for predicting interface thermal property changes by altering the interlayer torsion angle of gallium nitride provided by this invention has the following advantages compared with existing methods: (1) In view of the fact that the influence of alignment error on interface thermal properties during gallium nitride homoepitaxial process has not been solved, this invention proposes a controllable structural modeling and interface thermal property analysis method, and uses low-cost molecular dynamics technology to calculate the changes in the thermal properties of gallium nitride / gallium nitride interface when contacted at different torsion angles.

[0050] (2) This invention combines the quantum analysis of interface energy change and further elucidates the reason for the different interface thermal resistance under different torsion angles on the basic mechanism. This is very helpful for the testing and analysis of gallium nitride devices when using multi-physics fields in practical applications.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for predicting changes in interfacial thermal properties by altering the interlayer torsion angle of gallium nitride, characterized in that, include: Using a gallium nitride (GaN) substrate of a predetermined size, and an epitaxial layer of a larger GaN aligned with the center of the substrate, an initial-state molecular dynamics model is established. The substrate of this initial-state molecular dynamics model consists of m1×n1×h unit cells, and the epitaxial layer consists of m2×n2×h unit cells, satisfying the following quantitative relationships. , Where, M1 = m1 × a N1 = n1 × b, H = h × c a b and c are the lattice lengths of gallium nitride unit cells in the X, Y, and Z directions, respectively; The epitaxial layer is rotated according to a preset torsion angle, and the epitaxial layer is cut with the substrate size as a reference to obtain a computational model of the same size as the substrate interface, thereby forming a gallium nitride / gallium nitride thermal conduction system. The gallium nitride / gallium nitride thermal conduction system was subjected to stepwise relaxation using molecular dynamics simulation. After the system reached equilibrium, the energy and interface temperature during the steady-state simulation process were obtained. The interfacial thermal resistance under different torsion angles of contact was obtained based on the energy change and interfacial temperature difference when contacted at different torsion angles. The epitaxial layer is rotated according to a preset twist angle, and the epitaxial layer is cut using the substrate size as a reference to obtain a computational model of the same size as the substrate interface, including: Rotate the epitaxial layer in 5° increments within a range of 0° to 60°. Based on the cross-sectional size and boundary of the gallium nitride substrate, an epitaxial layer with the same size as the substrate interface is cut to form a computational model of the same size as the substrate interface.

2. The method for predicting interface thermal property changes by altering the interlayer torsion angle of gallium nitride according to claim 1, characterized in that, The established initial state molecular dynamics model is divided into eight functional layers from top to bottom according to different functions: fixation layer, heat source layer, Newton layer, epitaxial layer interface, substrate layer interface, Newton layer, heat sink and fixation layer.

3. The method for predicting interface thermal property changes by altering the interlayer torsion angle of gallium nitride according to claim 1, characterized in that, A stepwise relaxation of the gallium nitride / gallium nitride thermal conduction system was performed using molecular dynamics simulations. After the system reached equilibrium, the energy and interface temperature during the steady-state simulation were obtained, including: The conjugate gradient algorithm is used to optimize the energy of the atomic system to a minimum. In the isothermal and isobaric ensemble NPT, the initial temperature T0 of the system is set, and the atomic number, volume and temperature are kept constant for relaxation to eliminate the stress in the structure, so that the volume and pressure of the system reach thermodynamic equilibrium. In a canonical ensemble NVT, the system volume is kept constant to stabilize the system temperature at the target value; In the microcanonical ensemble NVE, the temperatures of the heat source and heat sink are controlled as follows: T h =T0×(1+δ)T s =T0×(1-δ;where T h T represents the temperature of the heat source. s δ represents the heat sink temperature, and δ is the normalized temperature difference factor. The steady-state heat transfer under different torsional angle contact states was analyzed by converting internal potential energy into kinetic energy. The system temperature was controlled by a Langevin thermostat, and energy and interface temperature were obtained during the steady-state heat transfer process.

4. The method for predicting interface thermal property changes by altering the interlayer torsion angle of gallium nitride according to claim 3, characterized in that, Also includes: When the gallium nitride / gallium nitride system relaxes in the NPT ensemble, non-periodic boundary conditions are set in the X-axis and Y-axis directions, and periodic boundary conditions are set in the Z-axis direction. During the relaxation of the NVT ensemble and the steady-state heat transfer process of the NVE ensemble, non-periodic boundary conditions are set in the X-axis and Y-axis directions, and fixed boundary conditions are set in the Z-axis direction.

5. The method for predicting interface thermal property changes by altering the interlayer torsion angle of gallium nitride according to claim 3, characterized in that, Also includes: The interactions between all nitrogen and gallium atoms in the substrate and epitaxial layer are described using the Tersoff interaction potential.

6. The method for predicting interface thermal property changes by altering the interlayer torsion angle of gallium nitride according to claim 1, characterized in that, The interfacial thermal resistance under different torsion angles is obtained based on the energy change and interfacial temperature difference during contact at different torsion angles, including: The heat flux can be calculated based on the energy changes at different torsional angles of contact. The interfacial thermal resistance is calculated based on the heat flux and the interfacial temperature difference.

7. The method for predicting changes in interfacial thermal properties by changing the interlayer torsion angle of gallium nitride according to claim 6, characterized in that, Based on the energy changes at different torsional angles of contact, the magnitude of the heat flux can be calculated, specifically: ； in, q The magnitude of heat flux; This refers to the total energy released by the heat source during a steady-state heat transport process. denoted as , where is the total energy absorbed by the heat sink; A is the atomic contact area at the interface.

8. The method for predicting changes in interfacial thermal properties by changing the interlayer torsion angle of gallium nitride according to claim 6, characterized in that, The interfacial thermal resistance is calculated based on the heat flux and the interfacial temperature difference, specifically as follows: ； in, The magnitude of the interfacial thermal resistance, This represents the temperature difference between the two ends of the interface.

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