Processing simulation analysis method for hard and brittle semiconductor material under graphene lubrication

Abstract

The invention discloses a processing simulation analysis method for a hard and brittle semiconductor material under graphene lubrication. The method comprises the following main steps: S1, establishing a molecular dynamics simulation model for processing the hard and brittle semiconductor material under graphene lubrication by adopting LAMMPS software; s2, performing force field parameter setting on the molecular dynamics simulation model in the S1; and S3, after programming, performing energy minimization and molecular dynamics balance on the model in the S2 in LAMMPS software. The method has the beneficial effects that the molecular dynamics simulation model for processing the hard and brittle semiconductor material under graphene lubrication is established on the basis of a molecular dynamics simulation theory, and processing simulation is performed on the hard and brittle semiconductor silicon material covered by graphene by optimizing configuration and reasonably setting simulation parameters.

Description

Technical Field

[0001] The invention relates to the technical field of computer molecular simulation methods, in particular to a hard and brittle semiconductor material processing simulation analysis method under graphene lubrication. Background Art

[0002] At present, silicon (Si) is a commonly used semiconductor material, which is widely used in aerospace, electronic communications, microwave devices and other fields. It is the core material for independent innovation and development and transformation and upgrading of strategic industries such as new generation mobile communications, national defense and military industry, and new energy. Therefore, the industry's performance requirements are becoming increasingly stringent. However, many semiconductor materials also have the characteristics of ceramic materials, which are hard and brittle, which brings difficulties to their high-quality processing and application.

[0003] The microstructure of a material determines its macroscopic properties. Some scholars have found that the thickness of the amorphous silicon layer will affect its heat transfer when testing the thermal conductivity of silicon materials. Other scholars have found that the structural changes of silicon crystals during processing are related to their initial configuration. Indentation and scratching are common processes in the processing of silicon crystal materials, which also affect the subsequent processing of silicon crystals and the quality of products. However, in industrial large-scale preparation, its microstructure and its change process are difficult to observe; graphene has excellent mechanical strength, ultra-thin thickness, atomically smooth surface and high chemical stability, and is an effective solid lubricant. In recent years, more and more researchers have studied the role of graphene. However, due to experimental conditions, it is still difficult to explain the role of graphene at the atomic level. Under nanoscale processing, the structural changes of hard and brittle semiconductor ceramic silicon bulk materials covered with graphene are a complex process, so it is very meaningful to study the processing of hard and brittle semiconductor materials under graphene lubrication.

[0004] Nano-processing technology is widely used in modern manufacturing industry. Nano-materials are also a hot topic in academic research. Many researchers have studied the mechanism of nano-processing process experimentally and theoretically. However, in the nano-processing process, there are few atomic layers on the processing surface, and the processing workpiece and processing tool are regarded as aggregates of atoms or molecules, which are essentially discrete and discontinuous, which brings challenges to the experimental observation of the processing process. On the other hand, nano-processing experiments have very high requirements for the working environment and the precision of processing equipment, which are difficult to meet with existing experimental conditions.

[0005] Molecular dynamics mainly relies on Newtonian mechanics to simulate the motion of molecular systems, and can observe the motion of each atom at the nanoscale, and is widely used to study the deformation of materials at the nanoscale. Therefore, we propose a new simulation method for processing hard and brittle semiconductor materials under graphene lubrication, which has simple steps, high reliability, can accurately predict the structural changes of semiconductor silicon materials, and provide scientific guidance for the processing of hard and brittle semiconductor materials, so as to optimize the design of material processing technology and improve material performance and application level. The computing platform used in the present invention has Lammps open source software, Python program, Ovito visualization software and Origin data processing software, which is applicable to Windows system and Linux system, and the computing environment is flexible, saving experimental time and experimental cost. Summary of the invention

[0006] The purpose of the present invention is to provide a method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication, comprising the following steps:

[0008] S1. Use LAMMPS software to establish a molecular dynamics simulation model for the processing of hard and brittle semiconductor materials under graphene lubrication;

[0009] S2, setting the force field parameters for the molecular dynamics simulation model in S1;

[0010] S3, after programming, perform energy minimization and molecular dynamics equilibrium on the model in S2 in LAMMPS software;

[0011] S4. Set the simulation parameters of the molecular dynamics simulation model, including simulation dimension, boundary conditions, potential function, ensemble selection, system temperature control method, simulation temperature and time step, and simulate the processing process to obtain simulation results under different processing processes:

[0012] S5. Process the output simulation results to characterize the structural changes of the workpiece.

[0013] As a preferred solution of the present invention: the molecular dynamics simulation model of hard and brittle semiconductor material processing under graphene lubrication using LAMMPS software in S1 specifically includes the following steps:

[0014] S11. Use LAMMPS software to create a hard and brittle semiconductor ceramic silicon block workpiece covered with graphene. The workpiece size is 21.7×10.8×13.6nm 3 ;

[0015] S12, establish a tool. The radius of the tool is 2.5nm, and it is located 2nm above the workpiece surface.

[0016] As a preferred solution of the present invention: the workpiece in S11 is a rectangle, and a substrate of other shapes can be established; the graphene in S11 can be set as multiple layers as needed; the tool in S12 is a ball, and other shapes such as a prism or a rounded shape can also be established.

[0017] As a preferred solution of the present invention: the force field parameters of the molecular dynamics simulation model in S1 are set using multiple force fields in S2, including Tersoff potential, Morse potential, LJ potential and Airebo potential functions, and the diamond tool is considered to be a rigid body. As a preferred solution of the present invention: the command for setting the force field parameters in S2 is as follows:

[0018] pair_style hybrid tersoff morse 8.5lj / cut 2.5airebo 3.0

[0019] As a preferred solution of the present invention: the energy minimization and molecular dynamics equilibrium of the model in S2 in the LAMMPS software after programming in S3 mainly include the following steps:

[0020] S31, set the initial temperature to 300K and the time step to 1 femtosecond;

[0021] S32. The system is first relaxed for 100ps, and then the changes in the temperature and potential energy of the atoms in the system are used to determine whether the system is in equilibrium, so that the constructed model has a stable configuration.

[0022] As a preferred solution of the present invention: the data of the simulation results in S4 include the three-dimensional coordinates, velocity and force of each atom in the simulation system.

[0023] As a preferred solution of the present invention: the boundary layer is fixed in the processing simulation in S4, the isothermal layer of the simulation process in S4 simulates heat exchange through a velocity scaling algorithm, and in the nano-scratch simulation, the non-periodic boundary condition (n-PBC) is applied to the X and Z directions, the periodic boundary (PBC) is applied to the Y direction, the time step is 1fs, and the indenter is pressed into the workpiece at a speed of 20m / s until the depth in the Z direction reaches 1nm. After that, the indenter scratches 10nm along the X direction at a speed of 20m / s.

[0024] As a preferred solution of the present invention: the processing of the output simulation results in S5 to characterize the structural changes of the workpiece uses Ovito software, Python program and Origin software to visualize the simulation data.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: based on the theory of molecular dynamics simulation, the present invention establishes a molecular dynamics simulation model for the processing of hard and brittle semiconductor materials under graphene lubrication, optimizes the configuration and reasonably sets the simulation parameters to simulate the processing of hard and brittle semiconductor silicon materials covered with graphene, and establishes a method for simulating the processing of hard and brittle semiconductor materials under graphene lubrication by analyzing the atomic phase change, the surface morphology of the processed workpiece, the subsurface damage layer, and the force of the processing tool. The present invention is applicable to Windows systems and Linux systems, has a flexible computing environment, and saves experimental time and experimental costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flowchart of a method for simulating processing of hard and brittle semiconductor materials under graphene lubrication implemented in the present invention;

[0027] Figure 2 A molecular dynamics simulation model diagram for the simulated processing of the present invention;

[0028] Figure 3 Atomic phase transition curve diagram obtained by implementing the present invention;

[0029] Figure 4 A surface topography of a machined workpiece obtained by implementing the present invention;

[0030] Figure 5 A workpiece subsurface damage layer map obtained by implementing the present invention;

[0031] Figure 6 This is a force diagram of a machining tool obtained by implementing the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figures 1 to 6 The present invention provides a technical solution: a method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication, comprising the following steps:

[0034] S1. Use LAMMPS software to establish a molecular dynamics simulation model for the processing of hard and brittle semiconductor materials under graphene lubrication;

[0035] S2, setting the force field parameters for the molecular dynamics simulation model in S1;

[0036] S3, after programming, perform energy minimization and molecular dynamics equilibrium on the model in S2 in LAMMPS software;

[0037] S4, setting the simulation parameters of the molecular dynamics simulation model, including simulation dimension, boundary conditions, potential function, ensemble selection, system temperature control method, simulation temperature and time step, and performing machining process simulation to obtain simulation results under different machining processes. Based on the theory of molecular dynamics simulation, this step simulates the machining of hard and brittle semiconductor silicon materials covered with graphene by reasonably setting simulation parameters. The tool first presses the workpiece down to 1nm, and then scratches at this depth.

[0038] S5. Process the output simulation results to characterize the structural changes of the workpiece. This simulation result adopts the characterization strategy of atomic number mapping and structural feature coloring, an innovative characterization method, with clear priorities and clear levels as the principle, to characterize the structural changes of the workpiece in multiple dimensions, predict the structural changes of semiconductor silicon materials at the atomic level, and the simulation results are highly reliable;

[0039] First, a molecular dynamics simulation model for the processing of hard and brittle semiconductor materials under graphene lubrication was established, and then each model was simulated at different processing temperatures. It was found that with the increase of temperature, the damaged area after indentation became more and more sharp. The presence of graphene coating affected the morphology of the subsurface damage layer (SDL). The thickness of SDL tended to increase with the increase of scratch distance. Due to the inhibitory effect of graphene coating, there were few debris in front of the tool during the scratching process on the workpiece surface, but more debris was left on the surface where the tool passed, forming a stronger wrinkle morphology, making the processed surface rougher at higher temperatures. This provides an atomic-level understanding of the processing of hard and brittle materials under graphene coating, is conducive to clarifying the internal structure evolution of the workpiece during the processing, and provides scientific guidance for the processing of hard and brittle semiconductor materials, so as to optimize the design of material processing technology and improve material performance and application level. The computing environment of the present invention is flexible, saving experimental time and experimental costs.

[0040] Among them, the molecular dynamics simulation model of hard and brittle semiconductor material processing under graphene lubrication using LAMMPS software in S1 specifically includes the following steps:

[0041] S11. Use LAMMPS software to create a hard and brittle semiconductor ceramic silicon block workpiece covered with graphene. The workpiece size is 21.7×10.8×13.6nm 3 .

[0042] S12, establish a tool. The radius of the tool is 2.5nm, and it is located 2nm above the workpiece surface.

[0043] The workpiece in S11 is a rectangle, and can also be established as a matrix of other shapes; the graphene in S11 can be set as multiple layers as needed; the tool in S12 is a ball, and can also be established as other shapes, such as a prism or a rounded shape.

[0044] Among them, S2 uses multiple force fields to set the force field parameters of the molecular dynamics simulation model in S1, including Tersoff potential, Morse potential, LJ potential and Airebo potential function. The command for setting the mixed potential function is as follows:

[0045] pair_style hybrid tersoff morse 8.5lj / cut 2.5airebo 3.0

[0046] Among them, after programming in S3, energy minimization and molecular dynamics equilibrium of the model in S2 are performed in LAMMPS software, which specifically includes the following steps:

[0047] S31, set the initial temperature to 300K and the time step to 1 femtosecond;

[0048] S32. The system is first relaxed for 100ps, and then the changes in the temperature and potential energy of the atoms in the system are used to determine whether the system is in equilibrium, so that the constructed model has a stable configuration.

[0049] The simulation result data in S4 include the three-dimensional coordinates, velocity and force of each atom in the simulation system.

[0050] Among them, the boundary layer is fixed in the machining process simulation in S4, and the isothermal layer of the simulation process in S4 simulates heat exchange through the velocity scaling algorithm. In the nano-scratch simulation, the non-periodic boundary conditions (n-PBC) are applied to the X and Z directions, and the periodic boundary (PBC) is applied to the Y direction. The time step is 1fs, and the indenter is pressed into the workpiece at a speed of 20m / s until the depth in the Z direction reaches 1nm. After that, the indenter scratches 10nm along the X direction at a speed of 20m / s. The Newton layer is the main deformation area, where the movement of atoms follows Newton's laws of motion.

[0051] Among them, S5 uses Ovito software, Python programming and Origin software to visualize the simulation data in order to process the output simulation results to characterize the structural changes of the workpiece. The change in the atomic position brings about a change in the coordination number of the central atom, so atoms with different coordination numbers can be used to characterize the atomic phase change in the workpiece; the workpiece is colored in the vertical direction to characterize the surface morphology of the processed workpiece; structural coloring is used to characterize workpiece damage; and force analysis is used to characterize tool wear.

[0052] Figure 3The phase change of atoms in a silicon workpiece covered with graphene at different processing temperatures with processing time. The perfect coordination number (CN) of silicon is 4, (a): CN = 3; (b): CN = 5; (c): CN = 6; (d): CN = 4. The morphology of the processed workpiece is characterized by coloring the coordinates of the atoms in the Z direction using Ovito software. Figure 4 It simulates the surface morphology of the workpiece under different processing temperatures during the processing. Figure 5 (a)-(e): Subsurface damage layer of crystalline Si coated with single-layer graphene. When the scratch distance is 10nm and the pressure depth is 1.0nm, the atoms are colored according to the diamond structure, where the gray ones are damaged atoms (graphene atoms are removed from the surface layer); (f): The number of defective atoms at different given temperatures. Figure 6 Time evolution of tool tangential force (a) and normal force (b) at different initial temperatures.

[0053] A method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication comprises the following steps:

[0054] S1. The molecular dynamics simulation model of the processing of hard and brittle semiconductor ceramic silicon blocks covered with graphene is established using LAMMPS software. The shapes of the workpiece and the tool can be realized through programming modeling as needed; the graphene can also be set to different layers as needed.

[0055] S2. Set the force field parameters for the molecular dynamics simulation model in S1. The force fields used include Tersoff potential, Morse potential, LJ potential and Airebo potential functions. The command for setting the mixed force field is as follows:

[0056] pair_style hybrid tersoff morse 8.5lj / cut 2.5airebo 3.0

[0057] S3, after programming, perform energy minimization and molecular dynamics equilibrium on the model in S2 in LAMMPS software. By setting parameters such as initial temperature, time step, relaxation time, and then judging whether the system is in equilibrium based on the changes in temperature and potential energy of atoms in the system, the constructed model has a stable configuration;

[0058] S4. Set the simulation parameters of the molecular dynamics simulation model, including simulation dimension, boundary conditions, potential function, ensemble selection, system temperature control method, simulation temperature and time step, and simulate the processing process. The boundary layer needs to be fixed during the processing process simulation, and the constant temperature layer simulates heat exchange through the velocity scaling algorithm. In the simulation, non-periodic boundary conditions (n-PBC) are applied to the X and Z directions, and periodic boundaries (PBC) are applied to the Y direction. The time step is 1fs, and the indenter is pressed into the workpiece at a speed of 20m / s until the depth in the Z direction reaches 1nm. After that, the indenter scratches 10nm at a speed of 20m / s along the X direction. The data of the simulation results under different processing processes include the three-dimensional coordinates, velocity and force of each atom in the simulation system

[0059] S5. The output simulation results were processed to characterize the structural changes of the workpiece. Ovito software, Python program and Origin software were used to visualize the simulation data.

[0060] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication, characterized in that: The following steps are involved: S1. Use LAMMPS software to establish a molecular dynamics simulation model for the processing of hard and brittle semiconductor materials under graphene lubrication; S2, setting the force field parameters for the molecular dynamics simulation model in S1; S3, after programming, perform energy minimization and molecular dynamics equilibrium on the model in S2 in LAMMPS software; S4, setting simulation parameters of the molecular dynamics simulation model, the simulation parameters including simulation dimension, boundary conditions, potential function, ensemble selection, system temperature control method, simulation temperature and time step, and performing machining process simulation to obtain simulation results under different machining processes; S5. Process the output simulation results to characterize the structural changes of the workpiece.

2. The method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication according to claim 1, characterized in that: The molecular dynamics simulation model of hard and brittle semiconductor material processing under graphene lubrication established by using LAMMPS software in S1 specifically includes the following steps: S11. Use LAMMPS software to create a hard and brittle semiconductor ceramic silicon block workpiece covered with graphene. The workpiece size is 21.7×10.8×13.6nm 3 ; S12, establish a tool. The radius of the tool is 2.5nm, and it is located 2nm above the workpiece surface.

3. The method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication according to claim 2, characterized in that: The workpiece in S11 is a rectangle, and other shapes of substrates can also be established; the graphene in S11 can also be set as multiple layers as needed; the tool in S12 is a ball, and other shapes such as a prism or rounded tool shape can also be established.

4. The method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication according to claim 3, characterized in that: The force fields used in S2 to set the force field parameters of the molecular dynamics simulation model in S1 include Tersoff potential, Morse potential, LJ potential and Airebo potential functions, and the diamond tool is considered to be a rigid body.

5. The method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication according to claim 4, characterized in that: The model in S2 has multiple atoms and uses a mixed potential function to describe the interatomic forces: The command to set the mixed potential function is as follows: pair_style hybrid tersoff morse 8.5lj / cut 2.5airebo 3.

0.

6. The method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication according to claim 5, characterized in that: After programming in S3, performing energy minimization and molecular dynamics equilibrium on the model in S2 in LAMMPS software specifically includes the following steps: S31, set the initial temperature to 300K and the time step to 1 femtosecond; S32. The system is first relaxed for 100ps, and then the changes in the temperature and potential energy of the atoms in the system are used to determine whether the system is in equilibrium, so that the constructed model has a stable configuration.

7. The method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication according to claim 6, characterized in that: The simulation result data in S4 includes the three-dimensional coordinates, velocity and force of each atom in the simulation system.

8. The method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication according to claim 7, characterized in that: The boundary layer is fixed in the machining process simulation in S4, and the isothermal layer simulated in S4 simulates heat exchange through a velocity scaling algorithm. In the nano-scratch simulation, non-periodic boundary conditions are applied in the X and Z directions, and periodic boundaries are applied in the Y direction. The time step is 1 fs, and the indenter is pressed into the workpiece at a speed of 20 m / s until the depth in the Z direction reaches 1 nm. After that, the indenter scratches 10 nm along the X direction at a speed of 20 m / s.

9. The method for simulating and analyzing the processing of hard and brittle semiconductor materials under graphene lubrication according to claim 8, characterized in that: The output simulation results in S5 are processed to characterize the structural changes of the workpiece, and Ovito software, Python programming and Origin software are used to visualize the simulation data.

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