CN117165806A - AlSiC composite material and preparation method and application thereof - Google Patents

Abstract

The application discloses an AlSiC composite material and a preparation method and application thereof, wherein the AlSiC composite material comprises a substrate, the substrate comprises a silicon carbide carrier, the silicon carbide carrier comprises a silicon layer positioned on the surface and aluminum in a gap of the silicon carbide carrier, and the silicon layer is provided with a groove; and disposing a carbon nanomaterial in the recess. Because the activity of the carbon nanomaterial arranged in the groove is greater than that of the silicon atom, the bonding probability between the carbon nanomaterial and the aluminum atom is greater than that between the carbon atom and the silicon atom, so that the migration quantity of the aluminum atom is increased, and the carbon nanomaterial is particularly arranged on the surface of the silicon carbide embedded with the atoms. At a certain temperature, the carbon nanomaterial embedded in the groove disperses the density of aluminum to a certain extent and increases the atom aggregation near the center line of symmetry of the liquid drop, thereby further improving the wettability in the preparation process of the composite material.

Description

AlSiC composite materials and their preparation methods and applications

Technical field

The invention relates to the field of metal matrix composite materials, and in particular to an AlSiC composite material and its preparation method and application.

Background technique

Aluminum-based silicon carbide (aluminum silicon carbon, hereafter referred to as AlSiC) composite materials have excellent mechanical properties and physical properties. The composite materials have high specific strength and specific stiffness, low thermal expansion coefficient, low density, high micro-yield strength, and good Due to its excellent mechanical and physical properties such as dimensional stability, thermal conductivity, wear resistance and fatigue resistance, it is widely used in aerospace, automotive, military, electronics, sports equipment and other fields.

AlSiC is an advanced metal-ceramic composite material, in which active soldered silicon carbide ceramic circuit boards have high reliability and heat dissipation capabilities. They are the preferred packaging materials for IGBT semiconductor devices in harsh environments. As a composite material of aluminum particles and silicon carbide, aluminum silicon carbon is prone to problems such as poor wettability between the ceramic phase and the substrate phase during the preparation process.

Contents of the invention

The main purpose of the present invention is to propose 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.

In order to achieve the above object, the present invention proposes an AlSiC composite material. The AlSiC composite material includes:

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

Carbon nanomaterials are arranged in the grooves.

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

The depth of the groove is 0.131-1.595nm.

Optionally, there are multiple grooves.

Optionally, there are multiple grooves, and the distance between adjacent grooves is 0.15-10 nm.

Optionally, the groove includes a wedge-shaped groove or a rectangular groove, wherein the slope of the wedge-shaped groove is less than 0.5.

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

The present invention also provides a method for preparing the above-mentioned AlSiC composite material. The preparation method includes the following steps:

S10. Provide a substrate. The substrate is a silicon carbide carrier. The silicon carbide carrier includes a silicon layer on the surface. Silicon atoms in the silicon layer are partially removed to obtain a silicon carbide layer with grooves. substrate;

S20. Add carbon nanomaterials into the groove to obtain substrate A;

S30. Diffuse liquid aluminum toward the substrate A to obtain an AlSiC composite material.

Optionally, step S10 includes: providing a substrate, the substrate being a silicon carbide carrier, the silicon carbide carrier including a silicon layer on the surface, adjusting the pulse energy of the laser to remove part of the silicon carbide layer on the surface silicon atoms to obtain a grooved silicon carbide substrate.

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

The present invention also provides a semiconductor device. The semiconductor device includes a packaging material. The packaging material is an AlSiC composite material. The AlSiC composite material is an AlSiC composite material according to any one of the above claims or is made of any of the above. Prepared by the preparation method of AlSiC composite material described in one item.

In the technical solution provided by the present invention, the AlSiC composite material includes a substrate and carbon nanomaterials. 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 nanomaterials are added to the grooves, and aluminum is provided in the silicon carbide carrier gap. Since the activity of the carbon nanomaterials disposed in the grooves is greater than the activity of silicon atoms, the carbon nanomaterials and The bonding probability between aluminum is greater than the bonding probability between carbon atoms and silicon atoms. Therefore, the migration amount of aluminum atoms is increased, especially on the surface of silicon carbide embedded with carbon atoms. At a certain temperature, the carbon nanomaterials embedded in the grooves disperse the density of aluminum to a certain extent and intensify the aggregation of atoms near the symmetry center line of the droplets, thus further improving the wetting during composite preparation. sex.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only For some embodiments of the present invention, those of ordinary skill in the art can also obtain other related drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic diagram of a unit cell box in an embodiment of the preparation process of the AlSiC composite material provided by the present invention;

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

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

The realization of the purpose, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

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 instructions or instructions. implying its relative importance or implicitly specifying the quantity of the technical feature indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In addition, the meaning of "and/or" appearing in the entire text includes three parallel solutions. Taking "A and/or B" as an example, it includes solution A, or solution B, or a solution that satisfies both A and B at the same time. In addition, the technical solutions in various embodiments can be combined with each other, but it must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that such a combination of technical solutions does not exist. , nor within the protection scope required by the present invention.

As an advanced metal-ceramic composite material, AlSiC has excellent thermal conductivity and is the preferred packaging material for IGBT semiconductor devices in harsh environments. As a composite material of aluminum particles and silicon carbide, AlSiC is prone to problems such as mismatch in processing and mechanical properties, uneven distribution of reinforced particles, and poor wettability during the preparation process.

In view of this, the present invention proposes an AlSiC composite material and a preparation method thereof.

The invention proposes an AlSiC composite material. The AlSiC composite material includes a substrate and carbon nanomaterials. The substrate includes a silicon carbide carrier. The silicon carbide carrier includes a silicon layer located on the surface, and a gap between the silicon carbide carrier. The aluminum in the silicon layer is provided with grooves; and the carbon nanomaterial is provided in the grooves.

It should be noted that the AlSiC composite material of the present invention needs to use 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. In the present invention, molten aluminum is diffused into the carbon layer. Among the gaps between atoms and silicon atoms, in fact, the gap can be a gap between carbon atoms and carbon atoms or silicon atoms, or a gap between silicon atoms and silicon atoms. Furthermore, the present invention has a surface layer A groove is provided on the silicon layer, and the carbon nanomaterial is placed in the groove. Since the activity of the carbon nanomaterial placed in the groove is greater than the activity of the silicon atoms, the probability of the combination between the carbon nanomaterial and the aluminum atom is greater than The bonding probability between carbon atoms and silicon atoms, therefore, increases the amount of migration of aluminum atoms, especially on the silicon carbide surface where the atoms are embedded. 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 symmetrical center line of the aluminum droplets, thus further improving the efficiency of the composite material preparation process. Wettability, where wetting means wetting. Wetting or non-wetting are two mutually exclusive physical phenomena. If a liquid infiltrates a solid and there are capillaries inside the solid, the liquid will penetrate into the solid under the action of capillary force.

It should be noted that the grooves can be etched on the silicon layer of the silicon carbide surface by selecting specific laser parameters. In this way, the grooves can subsequently induce aluminum atoms in the grooves based on the microstructure. The diffusion, and with the help of deposited carbon, makes wetting more likely to occur at the composite interface.

Further, the width of the groove is 0.438-2.49nm, for example, it can be 0.438nm, 0.448nm, 0.547nm, 0.625nm, 0.657nm, 0.748nm, 0.825nm, 0.925nm, 1.37nm, 2.35nm, 2.49 nm, etc., within the above range, expanding the cell according to the lattice constant to obtain the size will make the wettability of AlSiC the best. In actual operation, if you take an integer, it is easy to cut off some atoms, which will affect the force between atomic bonds. It has an impact, causing the physical properties of AlSiC to be damaged to a certain extent.

Further, the depth of the groove is 0.131-1.595nm, for example, it can be 0.131nm, 0.157nm, 0.258nm, 0.36nm, 0.394nm, 0.83nm, 1.35nm, 1.57nm, 1.595nm, etc., within the above range Within, AlSiC has the best wettability effect.

Further, there are multiple grooves. Specifically, referring to Figures 2 and 3, multiple grooves only need to be consistent in the Y-axis direction, which is more conducive to laser processing.

Further, there are multiple grooves, and the distance 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 interfered by the bonding force of other grooves, making the AlSiC wettability effect the best.

Further, the groove includes a wedge-shaped groove or a rectangular groove, wherein the slope of the wedge-shaped groove is less than 0.5.

It should be noted that, in fact, the groove can have other grooves, such as V-shaped groove, wedge-shaped groove or rectangular groove, preferably a wedge-shaped groove. If the present invention is set to a wedge-shaped groove, 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. The slope here refers to the ratio of the vertical height and horizontal width of the wedge-shaped groove. The larger the value, the steeper the slope. In this range For grooves within the value, since the difference between the two forces on the inclined wall experienced by the aluminum droplets is significantly larger than that of the vertical rectangular grooves, the surface migration of aluminum atoms is further increased, making the prepared composite material better wettable.

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

Please refer to Figure 1. In this embodiment, the preparation method of the AlSiC composite material includes the following steps:

S10. Provide a substrate. The substrate is a silicon carbide carrier. The silicon carbide carrier includes a silicon layer on the surface. The silicon atoms in the silicon layer are partially removed to obtain a substrate with grooves in the silicon carbide layer. ;

S20. Add carbon nanomaterials into the groove to obtain substrate A;

S30. Diffuse liquid aluminum toward the substrate A to obtain an AlSiC composite material.

Using the above method, liquid aluminum is diffused into the gap of the grooved silicon carbide substrate, and the wettability of the composite material obtained is better.

Further, step S10 also includes: providing a substrate, the substrate being a silicon carbide carrier, the silicon carbide carrier including a silicon layer on the surface, adjusting the pulse energy of the laser to remove the silicon layer on the surface of the silicon carbide. part of the silicon atoms to obtain a grooved silicon carbide substrate.

Specifically, when performing step S10, the following steps can be performed: adjust the pulse energy of the laser to remove some silicon atoms in the surface layer of silicon carbide to obtain a silicon carbide substrate with grooves. The selected laser includes: At least one of second laser, picosecond laser, diode pumped Nd:YAG laser and fiber laser.

Specifically, in actual operation, the following steps can be followed: by adjusting the pulse energy of the laser to determine the removal depth and width of the material, and using laser marking to remove some atoms on the silicon-based surface. The present invention adopts a vector scanning mode laser marking system to operate.

It should be noted that the size parameters such as the width or depth of the groove can be realized 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. Reduce the spot range and increase the number of pulses to process the pits on the surface of silicon carbide to a certain depth, so that the required grooves can be processed in the silicon layer on the surface of silicon carbide.

In S20, carbon nanomaterials are added into the groove to obtain substrate A.

Specifically, when performing step S20, the following steps can be performed: using mechanical force to press the carbon nanomaterial into the processed groove, where the mechanical force is subject to the premise that the Si-C bond on the SiC surface is not destroyed. .

In some embodiments, the specific operation is as follows: without destroying the Si-C bonds on the SiC surface, a mechanical force of 10-15 MPa is used to press carbon materials such as graphite into the grooves on the SiC surface.

S30. Diffuse liquid aluminum toward the substrate A to obtain an AlSiC composite material.

Specifically, when step S30 is performed, the following steps can be performed: solid aluminum is melted at high temperature into liquid aluminum, suspended on the substrate A and diffused into the gap.

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

It should be noted that the diffusion of droplets is due to the breakage of the Si-C bond. At this time, the dispersed A aluminum phase is produced in the interface reaction, thereby promoting interface wetting. In actual operation, wetting in the Al-SiC system is easily affected by the oxide film and the interfacial reaction after the oxide film breaks. These two stages partially overlap and there is no clear boundary. Increasing the temperature is beneficial 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 forms a strong chemical bond, the free energy of the interface will be significantly reduced, thereby greatly improving the wettability.

The present invention also provides a semiconductor device. The semiconductor device includes a packaging material. The packaging material is an AlSiC composite material. The AlSiC composite material is the AlSiC composite material provided above or prepared by the AlSiC composite material preparation method provided above. of.

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.

Example devices may be either diodes or transistors.

The technical solution of the present invention will be further described in detail below with reference to specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

The relevant parameters of the composite materials of the above-mentioned Examples 1 to 5 and Comparative Examples 1 to 3 are shown in Table 1 below.

Table 1 Relevant parameter values of composite materials

Groove width(nm) Groove depth(nm) groove slope groove filler Remark Example 1 0.438 0.131 0.299 graphite Wedge groove Example 2 0.657 0.175 0.266 carbon nanotubes Wedge groove Example 3 0.657 0.219 0.333 carbon nanotubes Wedge 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 groove Example 7 4.38 1.595 0.25 Fullerene Wedge groove Comparative example 1 0.438 0.131 0.299 Wedge groove Comparative example 2 0.438 0.131 Rectangular slot Comparative example 3 No groove

Example 1

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

Example 2

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

Example 3

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

Example 4

The AlSiC composite material includes a silicon carbide carrier with a silicon layer on the surface, and a laser is used to create rectangular grooves on the silicon layer, and carbon nanotubes are added to the grooves. The width of the rectangular grooves is 0.657nm and the depth is 0.175nm.

Example 5

The AlSiC composite material includes a silicon carbide carrier with a silicon layer on the surface, and a laser is used to create rectangular grooves on the silicon layer, and carbon nanotubes are added to the grooves. The width of the rectangular grooves is 0.657nm and the depth is 0.219nm.

Example 6

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

Example 7

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

Example 8

(1) Use a laser to create wedge-shaped grooves in the silicon layer on the surface of silicon carbide;

(2) Press the graphite material into the wedge-shaped groove using mechanical indentation to obtain substrate A;

(3) Melt the solid aluminum into aluminum droplets at a high temperature of 1200K, suspend the aluminum droplets on the substrate A, wait for the aluminum to diffuse into the gaps in the substrate A, and obtain the precipitate from the solid-liquid separation of the reaction liquid described in the AlSiC composite material. , wash and dry the precipitate to obtain a composite material.

Example 9

(1) Use a laser to create rectangular grooves in the silicon layer on the surface of silicon carbide;

(2) Press the graphite material into the rectangular groove using mechanical indentation to obtain substrate A;

(3) Melt the solid aluminum into a liquid column of aluminum at a high temperature of 1200K, suspend the liquid column of aluminum on the substrate A, wait for the aluminum to diffuse into the gaps in the substrate A, and obtain the precipitate from the solid-liquid separation of the reaction liquid described in the AlSiC composite material. , wash and dry the precipitate to obtain a composite material.

Comparative example 1

Except that graphite is not added to the wedge-shaped groove, the remaining steps and conditions are the same as in Example 1.

Comparative example 2

Except that carbon nanotubes are not added to the rectangular grooves, the remaining steps and conditions are the same as in Example 4.

Comparative example 3

No grooves are made, so other carbon nanomaterials are not added to the grooves. The remaining steps and conditions are the same as in Example 1.

Conduct performance tests on the composite materials prepared in Examples 1 to 7 and Comparative Examples 1 to 3. The measurement methods are as follows:

It should be noted that molecular dynamics simulation usually uses Newtonian mechanics principles to simulate the motion of molecular systems, extract sample data from the system composed of molecular states, and calculate the configuration integral of the system. The time step is 1fs, and the aluminum droplet density distribution of the last 100ps is collected every 1ps. Based on the integration results, the thermodynamic physical quantities of the system are further obtained, such as interaction energy, self-diffusion coefficient, contact angle, etc. During the calculation process, temperature control simulation was used. The temperature of the aluminum droplets varied between 900 and 1450K, and there was no atomic overlap or loss from the initial time to the steady state. Therefore, no unit cell optimization or energy minimization was used in the simulations. Since there are both aluminum metal atoms and silicon and carbon solid non-metal atoms in the system, three potential functions, Tersoff, EAM and 12-6LJ, are used to calculate the interaction between atoms. In order to avoid excessive energy loss in the system and achieve stability as soon as possible, the initial distance between the aluminum droplets and the silicon carbide matrix was set to 0.25 nm.

It should be noted that: for example, to model the process of preparing the composite materials of Example 1 and Example 2, the present invention uses LAMMPS software to establish a system model for subsequent testing. First, use the region command to build 3C-SiC respectively. The substrate and spherical aluminum droplets are shown in Figures 1-3. 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 within the unit cell is also defined. The position vector of the base atoms in the unit cell is a linear combination of the three edge vectors of the unit cell. Expand the single unit cell 20 times along the X, Y, and Z directions to establish a unit cell box, as shown in Figure 1. The unit cell box is divided into two parts along the z direction. In Region 1, all silicon atoms and carbon atoms in the area 19 times the height of the single unit cell are removed. In area 2, an area 1 times the height of the single unit cell is reserved to construct a silicon carbide substrate whose upper surface is entirely composed of silicon atoms. Then, face-centered cubic (fcc) single crystal aluminum droplets with a lattice constant of 0.405 nm were generated in region 1. The fcc lattice contains four basis atoms, one at the corner of the cubic surface and three at the center of the cubic surface. The center of mass of the aluminum droplet coincides with the center of the aluminum atomic lattice, and the cell expansion is repeated 10 times, 20 times, and 4 times in the X, Y, and Z directions respectively. The droplet radius is 2.5 times the lattice spacing.

On the upper surface of the silicon terminal 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, as shown in Figure 2. Subsequently, carbon atoms are filled into the wedge-shaped grooves to construct a system of embedded atoms in the wedge-shaped grooves (WA), as shown in Figure 3. In the same method, some atoms are removed to form a rectangular groove surface (RG) and a system with atoms embedded in the rectangular groove (RA).

This article uses molecular dynamics methods to first obtain the performance test results of Examples 1 to 7 and Comparative Examples 1 to 3 at 1250K, as shown in Table 2. Next, at a temperature of 900 to 1450 K, the wetting angle, interfacial energy and self-diffusion coefficient of the aluminum droplets in Example 1 and Comparative Examples 1 to 3 were obtained, as shown in Table 3-5.

It should be noted that: the wetting angle refers to the angle between the liquid-solid interface and the tangent line of the liquid surface at the contact point between the liquid phase and the solid phase. When the angle is less than 90°, it means wetting, and when it is greater than 90°, it means not wetting. The angle The smaller it is, the better the wetting effect is.

Interface energy: Interface energy refers to the increment of internal energy per unit interface system under constant temperature and constant pressure conditions. The presence of an interface generally affects all thermodynamic parameters of the system. There are two commonly used models to demonstrate interface phenomena: the Gibbs ideal interface model and the Guggenheim model. To demonstrate the thermodynamics of an interface system using the Gibbs model, the system can be divided into three parts: two immiscible liquids with volumes V _α and V _β , and an infinitely thin boundary layer called the Gibbs dividing plane (σ), which separates the two volumes, the smaller the absolute value of the interface energy coefficient, the smaller the increase in internal energy of the system, and the easier it is to reach thermodynamic equilibrium.

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:

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 respectively, N is the number of atoms in the system, and <...> is the ensemble average.

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

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

Compared with Examples 4 and 5, the wettability of Examples 1 and 2 is higher. This is because the aluminum droplets in Example 4 will be hindered by the vertical groove wall in the x-axis direction, causing the aluminum liquid to The intermolecular liquid-gas tension σ _SL of the drop is smaller than the solid-gas tension σ _SG , and on the inclined walls of the wedge-shaped grooves in Examples 1 and 2, the difference between the two forces experienced by the Al droplets is significantly greater than that of the rectangular grooves. , further increases the surface migration of aluminum atoms, therefore, there is a greater obstacle to the diffusion of aluminum droplets to a certain extent in Examples 4 and 5.

It can be seen from Examples 1 to 7 and Comparative Examples 1 and 2 that by setting grooves in the surface silicon layer of silicon carbide and adding carbon nanomaterials in the grooves, a composite material with high wettability can be obtained, in which the wedge-shaped concave The effect of grooves is the best, followed by rectangular grooves. This is because on the one hand, the liquid-solid contact interface between aluminum droplets and carbon atoms is smaller than the liquid-gas interface before embedded atoms, which reduces the potential barrier for droplet diffusion; on the other hand, , in the LJ potential function, the potential well depth between Al-C atoms is 0.0309eV, and the potential well depth between Al-Si atoms is 0.0195eV. The bonding between aluminum atoms and carbon atoms requires greater potential energy. . These two reasons further reduce the system interface energy of carbon atoms embedded in the trench. In Comparative Example 1, no carbon nanomaterial was added into the wedge-shaped groove, and in Comparative Example 2, no carbon nanomaterial was added into the rectangular groove. The effects of Examples 1-7 are better than those of Comparative Example 1-2, indicating that the above-mentioned carbon nanomaterials are added into the groove. Carbon nanomaterials, because the probability of carbon nanomaterials combining with aluminum atoms is greater than the probability of carbon nanomaterials combining with silicon atoms, therefore, the migration of aluminum atoms is increased, making the silicon carbide surface with embedded atoms more susceptible to droplet displacement, thus obtaining High wettability.

It can be seen from Examples 1 to 7 that the experimental results can also be affected by setting the size of the groove in the silicon carbide layer. The width of the groove in Examples 1 to 7 is 0.438-2.49nm and the depth is 0.131-1.595nm. If it is a wedge-shaped groove, the slope must be no less than 0.5. The AlSiC composite material obtained in this way has the best wettability. If the groove slope exceeds this value, the effect will be slightly worse. This is because the larger the value, the steeper the slope, and the difference between the two forces in the direction of the inclined wall experienced by the aluminum droplet is obviously closer to a rectangular groove with a vertical wall. The surface migration of aluminum atoms is reduced, making the wettability of the prepared composite material worse.

From Examples 1-7 to Comparative Example 3, it can be seen that by laser drilling grooves in the silicon carbide material with a silicon layer on the surface, compared with Comparative Example 3, no grooves are made, and grooves are made but non-carbon nanometers are made in the grooves. Comparing materials, the effect of Examples 1-5 is significantly better than that of Comparative Example 3. This is because the activity of carbon atoms is greater than the activity of silicon atoms, and the probability of combining carbon atoms with aluminum atoms is greater than the probability of combining carbon atoms with silicon atoms, which increases It reduces the surface migration of aluminum atoms and is more conducive to the subsequent diffusion of aluminum atoms, thereby further improving the wettability.

Perform performance tests on Example 1 (WA system) and Comparative Examples 1, 2 and 3 in the wetting stage at 900-1450K. The experimental results are shown in Table 3:

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

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

It can be seen from Table 3 that the wetting angles of aluminum droplets in the system with atoms embedded in the wedge-shaped grooves are all less than 90.0°, indicating that the droplets are completely wetted at 900 to 1450K. Among them, the wetting angle is the smallest at 1250K, about 72.5°. Comparing the wetting angles of the wedge-shaped groove system before and after embedded atoms, it was found that the wetting angle of the system after embedded atoms was smaller than that of the system without embedded atoms at most temperatures. Only at 1200K, the wetting angle of the system after embedded atoms was slightly smaller than that of the system without embedded atoms. It is about 0.5° larger than the unembedded atomic system. This phenomenon shows that after embedding carbon atoms, the wettability of the wedge-shaped groove system is significantly improved.

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

It can be seen from Table 4 that at the same temperature, the interface energy of the rectangular groove and wedge-shaped groove systems with embedded atoms is significantly lower than that of the rectangular groove and wedge-shaped groove systems without embedded atoms. Especially at 1050K, the interface energy of the rectangular groove system with embedded atoms is about -19.9kJ/mol, which is the lowest among the five systems. On the one hand, the liquid-solid contact interface between aluminum droplets and carbon atoms is smaller than the liquid-gas interface before embedded atoms, which reduces the potential barrier for droplet diffusion; on the other hand, in the LJ potential function, the potential between Al-C atoms The well depth is 0.0309eV, the potential well depth between Al-Si atoms is 0.0195eV, and the bonding between aluminum atoms and carbon atoms requires greater potential energy. These two reasons further reduce the system interface energy of carbon atoms embedded in the trench.

Table 5 Self-diffusion coefficient (nm ² ) results of Example 1 and Comparative Examples 1-3 at different temperatures

It can be seen from Table 5 that at 1400K, the diffusion coefficient of the wedge-shaped groove system is 7.3×10 ^-4 nm ² , which is the largest among all systems. Before and after embedding atoms, the diffusion rate of aluminum droplets in the wedge-shaped groove system does not change significantly, and the wetting angle after embedding atoms is significantly smaller than that without embedding atoms. Compared with the rectangular groove system with embedded atoms, the diffusion coefficient of the wedged groove system with embedded atoms is slightly larger except at 1150K and 1200K, indicating that although the wedged grooves will hinder the diffusion of aluminum atoms to a certain extent, when carbon atoms are embedded in the wedged grooves And after the carbon atoms are combined with the aluminum atoms, the diffusion of the aluminum droplets will be greatly improved, so the wetting angle of the droplets will be reduced and its wettability will be increased.

To sum up, 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 placed in the grooves. Since the activity of the carbon nanomaterial disposed in the groove is greater than the activity of silicon atoms, the bonding probability between the carbon nanomaterial and aluminum atoms is greater than the bonding probability between carbon atoms and silicon atoms, therefore, the migration amount of aluminum atoms is increased. , especially on the surface of silicon carbide with embedded atoms. At a certain temperature, the aluminum droplets located in the grooves will be in the wet stage, so that the carbon nanomaterials embedded in the grooves disperse the density of the aluminum droplets to a certain extent and enhance the atoms near the symmetry center line of the droplets. Aggregation, therefore, further improves the wettability of the composite.

The above are only preferred embodiments of the present invention, which do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the patent protection scope of the present invention.

Claims (10)

1. An AlSiC composite material, characterized in that the AlSiC composite material comprises:

a substrate comprising a silicon carbide carrier comprising a silicon layer on a surface, and aluminum in the silicon carbide carrier gap, the silicon layer being provided with a recess; the method comprises the steps of,

and the carbon nanomaterial is arranged in the groove.

2. The AlSiC composite material of claim 1,

the width of the groove is 0.438-2.49nm; and/or the number of the groups of groups,

the depth of the groove is 0.131-1.595nm.

3. The AlSiC composite of claim 1, wherein the recess is provided in plurality.

4. The AlSiC composite material of claim 1 or 2, characterized in that the grooves are provided in plural, and the interval between adjacent grooves is 0.15-10nm.

5. The AlSiC composite of claim 1, wherein the groove comprises a wedge groove or a rectangular groove, wherein the slope of the wedge groove is less than 0.5.

6. The AlSiC composite material of claim 1, wherein the carbon nanomaterial comprises any one of graphite, graphene, and carbon nanotubes.

7. A method of producing the AlSiC composite material of any one of claims 1 to 6, characterized by comprising the steps of:

s10, providing a substrate, wherein the substrate is set as a silicon carbide carrier, the silicon carbide carrier comprises a silicon layer positioned on the surface, and silicon atoms in the silicon layer are partially removed to obtain a substrate with grooves on the silicon carbide layer;

s20, adding the carbon nanomaterial into the groove to obtain a substrate A;

and S30, diffusing liquid aluminum to the substrate A to obtain the AlSiC composite material.

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

9. The method of producing AlSiC composite material of claim 7, wherein in step S30, the liquid aluminum comprises aluminum liquid droplets or aluminum liquid column.

10. A semiconductor device comprising an encapsulation material, the encapsulation material being an AlSiC composite, wherein the AlSiC composite is an AlSiC composite as claimed in any one of claims 1 to 6 or is produced by a method of producing an AlSiC composite as claimed in any one of claims 7 to 9.