AlSiC composite material and its preparation method and application

Abstract

The present invention discloses an AlSiC composite material, a preparation method thereof, and an application thereof. The AlSiC composite material includes a substrate, the substrate includes a silicon carbide carrier, the silicon carbide carrier includes a silicon layer located on the surface, and aluminum in the gaps of the silicon carbide carrier, the silicon layer is provided with grooves; and carbon nanomaterials are arranged in the grooves. Since the activity of the carbon nanomaterials arranged in the grooves is greater than that of silicon atoms, the probability of binding between the carbon nanomaterials and aluminum atoms is greater than the probability of binding between carbon atoms and silicon atoms, thereby increasing the migration amount of aluminum atoms, especially on the silicon carbide surface embedded with atoms. At a certain temperature, the carbon nanomaterials embedded in the grooves disperse the density of aluminum to a certain extent and increase the aggregation of atoms near the center line of symmetry of the droplet, thereby further improving the wettability during the preparation of the composite material.

Description

Technical Field

[0001] The present invention relates to the field of metal matrix composite materials, and in particular to an AlSiC composite material and a preparation method and application thereof. Background Art

[0002] Aluminum-based silicon carbide (aluminum silicon carbon, hereinafter referred to as AlSiC) composite materials have excellent mechanical and physical properties. The composite materials have high specific strength and specific stiffness, low thermal expansion coefficient, low density, high micro-yield strength, good dimensional stability, thermal conductivity, as well as wear resistance and fatigue resistance. They are widely used in aerospace, automobile, military, electronics, sports equipment and other fields.

[0003] AlSiC is an advanced metal-ceramic composite material. Actively brazed silicon carbide ceramic circuit boards offer high reliability and heat dissipation, making them the preferred packaging material for IGBT semiconductor devices in harsh environments. Aluminum silicon carbide, a composite material of aluminum particles and silicon carbide, is prone to poor wettability between the ceramic and substrate phases during its preparation. Summary of the Invention

[0004] The main purpose of the present invention is to provide an AlSiC composite material and its preparation method and application, aiming to provide a composite material with good wettability between the ceramic phase and the substrate phase.

[0005] To achieve the above object, the present invention provides an AlSiC composite material, comprising:

[0006] A substrate comprising a silicon carbide carrier, the silicon carbide carrier comprising a silicon layer on the surface and aluminum in the gaps of the silicon carbide carrier, the silicon layer being provided with grooves; and

[0007] The carbon nanomaterial is disposed in the groove.

[0008] Optionally, the width of the groove is 0.438-2.49 nm; and / or,

[0009] The depth of the groove is 0.131-1.595 nm.

[0010] Optionally, there are multiple grooves.

[0011] Optionally, there are a plurality of grooves, and the spacing between adjacent grooves is 0.15-10 nm.

[0012] Optionally, the groove comprises a wedge-shaped groove or a rectangular groove, wherein the slope of the wedge-shaped groove is less than 0.5.

[0013] Optionally, the carbon nanomaterial includes any one of graphite, graphene and carbon nanotubes.

[0014] The present invention also provides a method for preparing the above-mentioned AlSiC composite material, which comprises the following steps:

[0015] S10, providing a substrate, wherein the substrate is set as a silicon carbide carrier, the silicon carbide carrier includes a silicon layer located on the surface, and partially removing silicon atoms in the silicon layer to obtain a substrate with a silicon carbide layer having grooves;

[0016] S20, adding carbon nanomaterials into the groove to obtain substrate A;

[0017] S30, diffusing liquid aluminum into the substrate A to obtain an AlSiC composite material.

[0018] Optionally, step S10 includes: providing a substrate, wherein the substrate is set as a silicon carbide carrier, the silicon carbide carrier includes a silicon layer located on the surface, and adjusting the pulse energy of the laser to remove part of the silicon atoms in the silicon layer on the surface of the silicon carbide to obtain a silicon carbide substrate with grooves.

[0019] Optionally, in step S30, the liquid aluminum includes aluminum droplets or aluminum columns.

[0020] The present invention also provides a semiconductor device, comprising a packaging material, wherein the packaging material is an AlSiC composite material, wherein the AlSiC composite material is the AlSiC composite material according to any one of the above claims or is prepared by the preparation method of the AlSiC composite material according to any one of the above claims.

[0021] In the technical solution provided by the present invention, the AlSiC composite material includes a substrate and a carbon nanomaterial. The substrate includes a silicon carbide carrier, and the silicon carbide carrier includes a silicon layer located on the surface. The silicon layer is provided with grooves, and carbon nanomaterial is added to the grooves. Aluminum is also provided in the gaps of the silicon carbide carrier. Because the activity of the carbon nanomaterial provided in the grooves is greater than that of silicon atoms, the probability of binding between the carbon nanomaterial and aluminum is greater than the probability of binding between carbon atoms and silicon atoms. Therefore, the migration of aluminum atoms is increased, especially on the silicon carbide surface embedded with carbon atoms. At a certain temperature, the carbon nanomaterial embedded in the grooves disperses the density of the aluminum to a certain extent and intensifies the aggregation of atoms near the center line of symmetry of the droplet, thereby further improving the wettability during the preparation process of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of a unit cell box according to one embodiment of the preparation process of the AlSiC composite material provided by the present invention;

[0024] Figure 2 This is a schematic diagram of the system during the preparation process of Comparative Example 1 of the present invention;

[0025] Figure 3 This is a partial schematic diagram of the preparation process of Example 1 of the present invention.

[0026] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0028] It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0029] As an advanced metal-ceramic composite material with excellent thermal conductivity, AlSiC is the preferred packaging material for IGBT semiconductor devices in harsh environments. However, as a composite material of aluminum particles and silicon carbide, AlSiC is prone to problems during its preparation, such as mismatched processing and mechanical properties, uneven distribution of reinforcing particles, and poor wettability.

[0030] In view of this, the present invention provides an AlSiC composite material and a preparation method thereof.

[0031] The present invention proposes an AlSiC composite material, which includes a substrate and a carbon nanomaterial. The substrate includes a silicon carbide carrier, the silicon carbide carrier includes a silicon layer located on the surface, and aluminum in the gaps of the silicon carbide carrier, the silicon layer is provided with grooves; and the carbon nanomaterial is arranged in the grooves.

[0032] It should be noted that the AlSiC composite material of the present invention requires silicon carbide as a carrier, and the silicon carbide contains both a silicon layer and a carbon layer, but its surface layer is a silicon layer. The present invention diffuses molten aluminum into the gaps between carbon atoms and silicon atoms. In fact, the gaps can be gaps between carbon atoms and carbon atoms or silicon atoms, or gaps between silicon atoms and silicon atoms. Furthermore, the present invention provides grooves on the silicon layer of its surface layer and arranges carbon nanomaterials in the grooves. Since the activity of the carbon nanomaterials arranged in the grooves is greater than that of the silicon atoms, the probability of binding between the carbon nanomaterials and aluminum atoms is greater than the probability of binding between carbon atoms and silicon atoms. Therefore, the migration of aluminum atoms is increased, especially on the surface of silicon carbide embedded with atoms. At a certain temperature, the carbon nanomaterials embedded in the grooves disperse the density of aluminum to a certain extent and enhance the aggregation of atoms near the center line of symmetry of the aluminum droplet, thereby further improving the wettability of the composite material during preparation. Wetting is infiltration. Infiltration or non-infiltration are two mutually exclusive physical phenomena. If the liquid infiltrates the solid and there are capillaries inside the solid, the liquid will penetrate into the interior of the solid under the action of capillary force.

[0033] It should be noted that the grooves can be etched on the silicon layer on the surface of the silicon carbide by selecting specific laser parameters. In this way, the grooves can subsequently induce the diffusion of aluminum atoms in the grooves from a microscopic perspective, and with the help of deposited carbon, make wetting easier to occur at the interface of the composite material.

[0034] Furthermore, the width of the groove is 0.438-2.49 nm, for example, it can be 0.438 nm, 0.448 nm, 0.547 nm, 0.625 nm, 0.657 nm, 0.748 nm, 0.825 nm, 0.925 nm, 1.37 nm, 2.35 nm, 2.49 nm, etc. Within the above range, the size is obtained by expanding the cell according to the lattice constant, which will make the wettability of AlSiC best. In actual operation, if an integer is taken, some atoms are easily cut off, which affects the force between atomic bonds and causes a certain degree of damage to the physical properties of AlSiC.

[0035] Furthermore, the depth of the groove is 0.131-1.595 nm, for example, it can be 0.131 nm, 0.157 nm, 0.258 nm, 0.36 nm, 0.394 nm, 0.83 nm, 1.35 nm, 1.57 nm, 1.595 nm, etc. Within the above range, the wettability of AlSiC is the best.

[0036] Furthermore, the groove is provided with a plurality of grooves. Figure 2 and Figure 3 , it is only necessary to keep multiple grooves consistent in the Y-axis direction, which is more conducive to laser processing.

[0037] Furthermore, there are multiple grooves, and the spacing between adjacent grooves is 0.15-10nm, for example, it can be 0.15nm, 0.5nm, 0.8nm, 1nm, 3nm, 5nm, 8nm, 10nm, etc. Within the above range, the contents in the groove are not disturbed by the bonding force of other grooves, so that the wettability of AlSiC is best.

[0038] Furthermore, the groove includes a wedge-shaped groove or a rectangular groove, wherein the slope of the wedge-shaped groove is less than 0.5.

[0039] It should be noted that, in fact, the groove can be other grooves, such as V-grooves, wedge-shaped grooves or rectangular grooves, preferably wedge-shaped grooves. The present invention is set as a wedge-shaped groove, then the width of the wedge-shaped groove is 0.438-2.49nm, the depth of the wedge-shaped groove is 0.131-1.595nm and the slope of the wedge-shaped groove is less than 0.5. Here, the slope refers to the ratio of the vertical height to the horizontal width of the wedge-shaped groove. The larger this value is, the steeper the slope is. For grooves within this range of values, the difference between the two forces on the inclined wall exerted on the aluminum droplet is significantly greater than that of the vertical rectangular groove, which further increases the surface migration of aluminum atoms, making the prepared composite material more wettable.

[0040] Furthermore, in some embodiments, the carbon nanomaterial includes any one of graphite, graphene and carbon nanotubes, that is, the nanomaterial can be graphite, or graphene or carbon nanotubes, all of which can improve the wettability of the present invention. This is mainly because the activity of carbon atoms is greater than that of silicon atoms, and the probability of carbon atoms combining with aluminum atoms is greater than the probability of carbon atoms combining with silicon atoms, which increases the surface migration of aluminum atoms and is more conducive to the subsequent diffusion of aluminum atoms, thereby further improving the wettability.

[0041] See also Figure 1 In this embodiment, the preparation method of the AlSiC composite material includes the following steps:

[0042] S10, providing a substrate, wherein the substrate is set as a silicon carbide carrier, the silicon carbide carrier includes a silicon layer located on the surface, and partially removing silicon atoms in the silicon layer to obtain a substrate with a groove in the silicon carbide layer;

[0043] S20, adding carbon nanomaterials into the groove to obtain substrate A;

[0044] S30, diffusing liquid aluminum into the substrate A to obtain an AlSiC composite material.

[0045] By adopting the above method, liquid aluminum is diffused into the gap of the silicon carbide substrate with grooves, and the obtained composite material has better wettability.

[0046] Furthermore, step S10 also includes: providing a substrate, wherein the substrate is set as a silicon carbide carrier, the silicon carbide carrier includes a silicon layer located on the surface, and adjusting the pulse energy of the laser to remove part of the silicon atoms in the silicon layer on the surface of the silicon carbide to obtain a silicon carbide substrate with grooves.

[0047] Specifically, when performing step S10, the following steps can be followed: adjust the pulse energy of the laser to remove part of the silicon atoms in the surface layer of the silicon carbide to obtain a silicon carbide substrate with grooves, wherein the selected laser includes: at least one of: a femtosecond laser, a picosecond laser, a diode-pumped Nd:YAG laser and a fiber laser.

[0048] Specifically, in actual operation, the following steps can be followed: by adjusting the laser pulse energy to determine the material removal depth and width, a laser marking method is used to remove part of the silicon surface atoms. The present invention uses a vector scanning laser marking system to operate.

[0049] It should be noted that the size parameters such as the width or depth of the groove can be achieved by adjusting the parameters of the laser marking system. For example, the width of the groove can be expanded by expanding the spot range and reducing the laser scanning speed. The pits on the silicon carbide surface can be processed to a certain depth by reducing the spot range and increasing the number of pulses. In this way, the required grooves can be processed in the silicon layer on the silicon carbide surface.

[0050] In S20 , a carbon nanomaterial is added into the groove to obtain a substrate A.

[0051] Specifically, when performing step S20, the following steps may be performed: using mechanical force to press the carbon nanomaterial into the processed groove, wherein the mechanical force is applied without destroying the Si-C bond on the SiC surface.

[0052] In some embodiments, the specific operation is as follows: without destroying the Si-C bonds on the SiC surface, a carbon material such as graphite is pressed into the groove on the SiC surface using a mechanical force of 10-15 MPa.

[0053] S30, diffusing liquid aluminum into the substrate A to obtain an AlSiC composite material.

[0054] Specifically, when performing step S30, the process may be carried out through the following steps: solid aluminum is melted into liquid aluminum at a high temperature, and the liquid aluminum is suspended on the substrate A and diffused into the gap.

[0055] Furthermore, the liquid aluminum here is aluminum droplets or aluminum liquid columns, which are generally aluminum in a molten state formed by solid aluminum at a temperature of 900 to 1450K. The combination of silicon atoms and aluminum atoms under the substrate is more conducive to the diffusion of aluminum droplets on the silicon carbide surface, further increasing wettability.

[0056] It should be noted that the diffusion of the droplets is due to the breaking of the Si-C bond. At this time, a dispersed aluminum phase A is produced in the interfacial reaction, thereby promoting interfacial wetting. In actual operation, the wetting in the Al-SiC system is easily affected by the interfacial reaction after the oxide film and the oxide film rupture. These two stages partially overlap and have no clear boundary. Increasing the temperature is conducive to the deoxidation of the oxide film and accelerates the reaction between aluminum and silicon carbide. After adding silicon to aluminum, if the silicon is separated at the solid-liquid interface and a strong chemical bond is formed, the free energy of the interface will be significantly reduced, thereby greatly improving the wettability.

[0057] The present invention also provides a semiconductor device, which includes a packaging material, wherein the packaging material is an AlSiC composite material, and the AlSiC composite material is the AlSiC composite material provided above or is prepared by the AlSiC composite material preparation method provided above.

[0058] The semiconductor device may include any one of components or devices such as a rectifier, an oscillator, a light emitter, an amplifier, a photometer, etc., but is not limited thereto.

[0059] An exemplary device may be any of a diode and a transistor.

[0060] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0061] The relevant parameters of the composite materials of Examples 1 to 5 and Comparative Examples 1 to 3 are shown in Table 1 below.

[0062] Table 1 Relevant parameter values of composite materials

[0063] Groove width (nm) Groove depth (nm) Groove slope Groove filler Remark Example 1 0.438 0.131 0.299 graphite wedge-shaped groove Example 2 0.657 0.175 0.266 carbon nanotubes wedge-shaped groove Example 3 0.657 0.219 0.333 carbon nanotubes wedge-shaped groove Example 4 0.657 0.175 carbon nanotubes Rectangular slot Example 5 0.657 0.219 carbon nanotubes Rectangular slot Example 6 2.49 0.876 0.4 graphite wedge-shaped groove Example 7 4.38 1.595 0.25 Fullerene wedge-shaped groove Comparative Example 1 0.438 0.131 0.299 wedge-shaped groove Comparative Example 2 0.438 0.131 Rectangular slot Comparative Example 3 No groove

[0064] Example 1

[0065] The AlSiC composite material includes a silicon carbide carrier with a silicon layer on the surface, and a wedge-shaped groove is punched on the silicon layer with a laser, and graphite is added to the groove. The wedge-shaped groove has a width of 0.438 nm, a depth of 0.131 nm, and a slope of 0.299.

[0066] Example 2

[0067] The AlSiC composite material includes a silicon carbide carrier with a silicon layer on the surface, and a wedge-shaped groove is punched on the silicon layer with a laser, and carbon nanotubes are added to the groove. The rectangular groove has a width of 0.657nm, a depth of 0.175nm, and a slope of 0.266.

[0068] Example 3

[0069] The AlSiC composite material includes a silicon carbide carrier with a silicon layer on the surface, and a wedge-shaped groove is punched on the silicon layer with a laser, and carbon nanotubes are added to the groove. The rectangular groove has a width of 0.657nm, a depth of 0.219nm, and a slope of 0.333.

[0070] Example 4

[0071] The AlSiC composite material includes a silicon carbide carrier with a silicon layer on the surface, and rectangular grooves are punched on the silicon layer with a laser, and carbon nanotubes are added to the grooves, and the rectangular grooves have a width of 0.657 nm and a depth of 0.175 nm.

[0072] Example 5

[0073] The AlSiC composite material includes a silicon carbide carrier with a silicon layer on the surface, and rectangular grooves are punched on the silicon layer using a laser, and carbon nanotubes are added to the grooves, and the rectangular grooves have a width of 0.657 nm and a depth of 0.219 nm.

[0074] Example 6

[0075] The AlSiC composite material includes a silicon carbide carrier with a silicon layer on the surface, and a wedge-shaped groove is punched on the silicon layer with a laser, and graphite is added to the groove. The wedge-shaped groove has a width of 2.49 nm, a depth of 0.876 nm, and a slope of 0.4.

[0076] Example 7

[0077] The AlSiC composite material includes a silicon carbide carrier with a silicon layer on the surface, and a wedge-shaped groove is punched on the silicon layer with a laser, and fullerene is added to the groove. The wedge-shaped groove has a width of 4.38nm, a depth of 1.595nm, and a slope of 0.25.

[0078] Example 8

[0079] (1) Using laser to punch wedge-shaped grooves in the silicon layer on the surface of silicon carbide;

[0080] (2) Pressing the graphite material into the wedge-shaped groove by mechanical indentation to obtain substrate A;

[0081] (3) Melting solid aluminum into aluminum droplets at a high temperature of 1200K, suspending the aluminum droplets on substrate A, and waiting for the aluminum to diffuse into the gaps in substrate A to obtain an AlSiC composite material; separating the reaction liquid into a solid-liquid separation to obtain a precipitate, washing and drying the precipitate to obtain a composite material.

[0082] Example 9

[0083] (1) Using laser to punch rectangular grooves in the silicon layer on the surface of silicon carbide;

[0084] (2) Pressing the graphite material into the rectangular groove by mechanical indentation to obtain substrate A;

[0085] (3) Melting solid aluminum at a high temperature of 1200K to form an aluminum liquid column, suspending the aluminum liquid column on substrate A, and waiting for the aluminum to diffuse into the gaps in substrate A to obtain an AlSiC composite material; separating the reaction liquid into a precipitate through solid-liquid separation, and washing and drying the precipitate to obtain a composite material.

[0086] Comparative Example 1

[0087] Except that graphite is not added into the wedge-shaped groove, the remaining steps and conditions are the same as those in Example 1.

[0088] Comparative Example 2

[0089] Except that carbon nanotubes are not added into the rectangular grooves, the remaining steps and conditions are the same as those in Example 4.

[0090] Comparative Example 3

[0091] No grooves were formed, and therefore no other carbon nanomaterials were added into the grooves. The remaining steps and conditions were the same as those in Example 1.

[0092] The composite materials obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were subjected to performance tests, and the testing methods were as follows:

[0093] It should be noted that molecular dynamics simulations typically use Newtonian mechanics to model the motion of molecular systems. Sample data is extracted from the system's molecular states and the system's configuration integral is calculated. The time step is 1 fs, and the density distribution of the aluminum droplet is collected every 1 ps for the last 100 ps. The integrated results are used to further derive thermodynamic quantities of the system, such as interaction energy, self-diffusion coefficient, and contact angle. During the calculations, temperature control was used, with the aluminum droplet temperature varying between 900 and 1450 K. From the initial state to the steady state, there was no atomic overlap or loss. Therefore, no unit cell optimization or energy minimization was used in the simulations. Because the system contains both aluminum metal atoms and silicon and carbon solid non-metal atoms, the Tersoff, EAM, and 12-6LJ potential functions are used to calculate the atomic interactions. To avoid excessive energy loss and achieve stabilization as quickly as possible, the initial distance between the aluminum droplet and the silicon carbide substrate was set to 0.25 nm.

[0094] It should be noted that: For example, in the process of preparing the composite materials of Example 1 and Example 2, the present invention uses the system model established in LAMMPS software for subsequent testing. First, the region command is used to construct the 3C-SiC substrate and the spherical aluminum droplet respectively. Figure 1-3 As shown. Define a 3C-SiC single unit cell with three orthogonal unit vectors and a lattice length of approximately 0.438nm. At the same time, a list of base atoms placed in the unit cell is also defined. The position vectors of the base atoms in the unit cell are linear combinations of the three edge vectors of the unit cell. The single unit cell is expanded 20 times in the X, Y, and Z directions to create a unit cell box, as shown in Figure 1 As shown. The unit cell box is divided into two parts along the z direction. In region 1, all silicon atoms and carbon atoms within the area 19 times the height of the single unit cell are removed. In region 2, an area 1 times the height of the single unit cell is retained to construct a silicon carbide substrate whose upper surface is entirely made of silicon atoms. Then, a face-centered cubic (fcc) single crystal aluminum droplet with a lattice constant of 0.405nm is generated in region 1. The fcc lattice contains four base atoms, one at the corner of the cubic surface and the other three at the center of the cubic surface. The center of mass of the aluminum droplet coincides with the center of the aluminum atom lattice, and the cell expansion is repeated 10 times, 20 times and 4 times in the X, Y and Z directions, respectively, and the droplet radius is 2.5 times the lattice spacing.

[0095] On the upper surface of the silicon end system (Si), some atoms are removed to form a wedge-shaped groove surface and a wedge-shaped groove is established. This system is referred to as the WG system. Figure 2 Then, carbon atoms are filled into the wedge-shaped grooves to construct a system of atoms embedded in the wedge-shaped grooves (WA), as shown in Figure 3 In the same way, some atoms are removed to form a rectangular groove surface (RG) and a system of atoms embedded in the rectangular groove (RA).

[0096] This paper uses molecular dynamics analysis to first obtain the performance test results of Examples 1 to 7 and Comparative Examples 1 to 3 at 1250 K, as shown in Table 2. Next, the wetting angle, interfacial energy, and self-diffusion coefficient of the aluminum droplets in Example 1 and Comparative Examples 1 to 3 were obtained at temperatures between 900 and 1450 K, as shown in Tables 3-5.

[0097] It should be noted that the wetting angle refers to the angle between the liquid-solid interface and the tangent of the liquid surface at the contact point between the liquid phase and the solid phase. When the angle is less than 90°, it indicates wetting, and greater than 90° indicates non-wetting. The smaller the angle, the better the wetting effect.

[0098] Interface energy: Interface energy refers to the increment of internal energy per unit interface system under constant temperature and pressure conditions. The existence of an interface usually affects all thermodynamic parameters of the system. There are two commonly used models to demonstrate interface phenomena: Gibbs ideal interface model and Guggenheim model. In order to use the Gibbs model to demonstrate the thermodynamics of an interface system, the system can be divided into three parts: two with volume V α and V β immiscible liquids, and an infinitely thin boundary layer, called the Gibbs partition plane (σ), separating the two volumes. The smaller the absolute value of the interfacial energy coefficient, the smaller the increase in the internal energy of the system, and the easier it is to reach thermodynamic equilibrium.

[0099] Self-diffusion coefficient: The self-diffusion coefficient refers to the mean square displacement of a substance when the chemical potential gradient is zero, and can be expressed by the following formula:

[0100]

[0101] Among them, r i (t) and r i (0) are the position vectors of the i-th atom at any time t and the initial time, N is the number of atoms in the system, and <…> is the ensemble average.

[0102] Table 2 Performance test results of Examples 1 to 7 and Comparative Examples 1 to 3 at 1250K

[0103] Wetting angle (°) Interfacial energy (kJ / mol) <![CDATA[Self-diffusion coefficient (nm 2 )]]> Example 1 72.5 -14.75 <![CDATA[8.90×10 -7 ]]> Example 2 65.3 -17.52 <![CDATA[9.98×10 -5 ]]> Example 3 57.9 -19.04 <![CDATA[4.35×10 -5 ]]> Example 4 79.7 -18.70 <![CDATA[2.64×10 -5 ]]> Example 5 78.1 -17.66 <![CDATA[9.71×10 -5 ]]> Example 6 71.6 -42.39 <![CDATA[2.64×10 -4 ]]> Example 7 75.4 -45.40 <![CDATA[3.33×10 -4 ]]> Comparative Example 1 92.375 -10.80 <![CDATA[8.25×10 -5 ]]> Comparative Example 2 83.125 -10.91 <![CDATA[1.43×10 -4 ]]> Comparative Example 3 82 -10.42 <![CDATA[1.69×10 -4 ]]>

[0104] Compared with Examples 4 and 5, Examples 1 and 2 have higher wettability. This is because the aluminum droplets in Example 4 are hindered by the vertical groove wall in the x-axis direction, resulting in the intermolecular liquid-gas tension σ SL Less than solid-gas tension σ SGHowever, on the inclined wall of the wedge-shaped groove in Examples 1 and 2, the difference between the two forces on the Al droplet is significantly greater than that in the rectangular groove, further increasing the surface migration of aluminum atoms. Therefore, in Examples 4 and 5, the diffusion of the aluminum droplet is more hindered to a certain extent.

[0105] Examples 1 to 7 and Comparative Examples 1 and 2 show that by providing grooves in the surface silicon layer of silicon carbide and adding carbon nanomaterials to the grooves, a highly wettable composite material can be obtained. Wedge-shaped grooves offer the best results, followed by rectangular grooves. This is because, on the one hand, the liquid-solid interface between the aluminum droplet and the carbon atoms is smaller than the liquid-gas interface before the atoms are embedded, reducing the potential barrier for droplet diffusion. On the other hand, in the LJ potential function, the potential well depth between Al-C atoms is 0.0309 eV, while the potential well depth between Al-Si atoms is 0.0195 eV. Therefore, the bonding between aluminum atoms and carbon atoms requires greater potential energy. These two factors further reduce the interfacial energy of the system where carbon atoms are embedded in the grooves. While Comparative Example 1 did not add carbon nanomaterials into the wedge-shaped grooves, and Comparative Example 2 did not add carbon nanomaterials into the rectangular grooves, the effects of Examples 1-7 were all better than those of Comparative Examples 1-2, indicating that the carbon nanomaterials were added into the grooves. Since the probability of the carbon nanomaterials combining with aluminum atoms is greater than the probability of the carbon nanomaterials combining with silicon atoms, the migration of aluminum atoms is increased, making the silicon carbide surface with embedded atoms more prone to droplet displacement, thereby obtaining high wettability.

[0106] Examples 1 to 7 show that the size of the grooves in the silicon carbide layer can also influence the experimental results. In Examples 1 to 7, the grooves ranged from 0.438 to 2.49 nm in width and 0.131 to 1.595 nm in depth. For wedge-shaped grooves, a slope of at least 0.5 was sufficient, resulting in the best wettability for the AlSiC composite. However, if the groove slope exceeded this value, the effect was slightly less favorable. This is because a larger slope increases the steeper the slope, and the difference between the two forces acting on the aluminum droplet in the oblique wall direction is significantly closer to that of a rectangular groove with perpendicular walls. This reduces the surface migration of aluminum atoms and results in poor wettability of the resulting composite.

[0107] It can be seen from Examples 1-7 to Comparative Example 3 that by laser punching grooves in a silicon carbide material with a silicon layer on the surface, compared with Comparative Example 3 in which no grooves are punched, or in which grooves are punched but non-carbon nanomaterials are inside the grooves, the effects of Examples 1-5 are significantly better than Comparative Example 3. This is because the activity of carbon atoms is greater than that of silicon atoms, and the probability of carbon atoms combining with aluminum atoms is greater than the probability of carbon atoms combining with silicon atoms, which increases the surface migration of aluminum atoms and is more conducive to the subsequent diffusion of aluminum atoms, thereby further improving wettability.

[0108] The performance of Example 1 (WA system) and Comparative Examples 1, 2 and 3 was tested at 900-1450K in the wetting stage. The experimental results are shown in Table 3:

[0109] Table 3 Wetting angle (°) results of Example 1 and Comparative Examples 1-3 at different temperatures

[0110] Temperature (K) Si R RA W WA 900 90.375 92.125 79.75 81.5 74.75 950 75 83 79.875 96.25 77.75 1000 80 81.25 87 84.875 79.75 1050 83.875 84.25 79.25 86 79.25 1100 83.875 85.5 75.625 87.875 83.5 1150 76 85.375 87.375 87.5 86.125 1200 73.875 88.125 87.125 86.375 86.875 1250 82 83.125 88.375 92.375 72.5 1300 83.5 89.5 73.625 96.1 84.25 1350 78.5 92.625 91 88.875 84.75 1400 85.375 83.25 77.375 86.75 74.625 1450 80 85.75 89.5 86.5 79.5

[0111] Table 3 shows that the wetting angles of the aluminum droplet in the wedge-shaped groove with embedded atoms are all less than 90.0°, indicating complete wetting of the droplet between 900 and 1450 K. The wetting angle is lowest at 1250 K, approximately 72.5°. A comparison of the wetting angles of the wedge-shaped groove system before and after the embedded atoms reveals that the wetting angle of the embedded system is smaller than that of the unembedded system at most temperatures. Only at 1200 K is the wetting angle slightly larger, approximately 0.5°, than that of the unembedded system. This phenomenon indicates that the embedding of carbon atoms significantly improves the wettability of the wedge-shaped groove system.

[0112] Table 4 Interfacial energy (kJ / mol) results of Example 1 and Comparative Examples 1-3 at different temperatures

[0113]

[0114] Table 4 shows that at the same temperature, the interfacial energy of the rectangular and wedge-shaped groove systems with embedded atoms is significantly lower than that of the rectangular and wedge-shaped groove systems without embedded atoms. In particular, at 1050 K, the interfacial energy of the rectangular groove system with embedded atoms is approximately -19.9 kJ / mol, the lowest of the five systems. On the one hand, the liquid-solid contact interface between the aluminum droplet and the carbon atoms is smaller than the liquid-gas interface before the atoms are embedded, reducing the potential barrier for droplet diffusion. On the other hand, in the LJ potential function, the potential well depth between Al-C atoms is 0.0309 eV, and the potential well depth between Al-Si atoms is 0.0195 eV, requiring greater potential energy for bonding between aluminum and carbon atoms. These two factors further reduce the interfacial energy of the system with embedded carbon atoms in the groove.

[0115] Table 5 Self-diffusion coefficients (nm) of Example 1 and Comparative Examples 1-3 at different temperatures 2 )result

[0116]

[0117] From Table 5, we can see that at 1400K, the diffusion coefficient of the wedge-shaped groove system is 7.3×10 -4 nm 2, the largest of all systems. The diffusion rate of the aluminum droplet in the wedge-shaped groove system did not change significantly before and after the atoms were embedded, and the wetting angle after the atoms were embedded was significantly smaller than the wetting angle without the atoms. Compared with the rectangular groove system with embedded atoms, the diffusion coefficient of the wedge-shaped groove system with embedded atoms was slightly larger, except at 1150K and 1200K. This indicates that although the wedge-shaped groove hinders the diffusion of aluminum atoms to a certain extent, the embedding of carbon atoms in the wedge-shaped groove and the combination of carbon atoms with aluminum atoms greatly enhances the diffusion of the aluminum droplet, thereby reducing the wetting angle of the droplet and increasing its wettability.

[0118] In summary, in the AlSiC composite material proposed in this application, grooves are provided on the surface silicon layer of the silicon carbide carrier; and carbon nanomaterials are provided in the grooves. Since the activity of the carbon nanomaterials provided in the grooves is greater than that of silicon atoms, the probability of binding between the carbon nanomaterials and aluminum atoms is greater than the probability of binding between carbon atoms and silicon atoms. Therefore, the migration of aluminum atoms is increased, especially on the silicon carbide surface embedded with atoms. At a certain temperature, the aluminum droplets located in the grooves will be in a wetting stage, so that the carbon nanomaterials embedded in the grooves disperse the density of the aluminum droplets to a certain extent and enhance the aggregation of atoms near the center line of symmetry of the droplets, thereby further improving the wettability of the composite material.

[0119] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of the present invention.

Claims

1. An AlSiC composite material, characterized in that: The AlSiC composite material comprises: A substrate comprising a silicon carbide carrier, the silicon carbide carrier comprising a silicon layer on a surface thereof and aluminum in gaps within the silicon carbide carrier, the silicon layer being provided with grooves; and The carbon nanomaterial is disposed in the groove.

2. The AlSiC composite material according to claim 1, wherein The width of the groove is 0.438-2.49 nm; and / or, The depth of the groove is 0.131-1.595 nm.

3. The AlSiC composite material according to claim 1, wherein There are a plurality of grooves.

4. The AlSiC composite material according to claim 1 or 2, characterized in that There are a plurality of grooves, and the spacing between adjacent grooves is 0.15-10 nm.

5. The AlSiC composite material according to claim 1, wherein The groove includes a wedge-shaped groove or a rectangular groove, wherein the slope of the wedge-shaped groove is less than 0.

5.

6. The AlSiC composite material according to claim 1, wherein The carbon nanomaterial includes any one of graphite, graphene and carbon nanotubes.

7. A method for preparing the AlSiC composite material according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: S10, providing a substrate, wherein the substrate is set as a silicon carbide carrier, the silicon carbide carrier includes a silicon layer located on the surface, and partially removing silicon atoms in the silicon layer to obtain a substrate with a silicon carbide layer having grooves; S20, adding carbon nanomaterials into the groove to obtain substrate A; S30, diffusing liquid aluminum into the substrate A to obtain an AlSiC composite material.

8. The method for preparing the AlSiC composite material according to claim 7, wherein: Step S10 includes: providing a substrate, wherein the substrate is set as a silicon carbide carrier, the silicon carbide carrier includes a silicon layer located on the surface, and adjusting the pulse energy of the laser to remove part of the silicon atoms in the silicon layer on the surface of the silicon carbide to obtain a silicon carbide substrate with grooves.

9. The method for preparing the AlSiC composite material according to claim 7, wherein: In step S30, the liquid aluminum includes aluminum droplets or aluminum columns.

10. A semiconductor device, characterized in that: The semiconductor device includes a packaging material, and the packaging material is an AlSiC composite material, wherein the AlSiC composite material is the AlSiC composite material according to any one of claims 1 to 6 or is prepared by the preparation method of the AlSiC composite material according to any one of claims 7 to 9.

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