Previous Article in Journal
Fano Resonant Sensing in MIM Waveguide Structures Based on Multiple Circular Split-Ring Resonant Cavities
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Micromachines
Volume 16
Issue 2
10.3390/mi16020184
micromachines-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Mechanism of OH*-Modified 4H-SiC Surface with Scratches Based on ReaxFF MD Simulation

by
Dongxiao Yan
1,2,
Hui Huang
1,2,3,
Mingpu Xue
1,2 and
Nian Duan
1,3,*
1
Institute of Manufacturing Engineering, Huaqiao University, Xiamen 361021, China
2
State Key Laboratory of High-Performance Tools, Huaqiao University, Xiamen 361021, China
3
College of Mechanical Engineering and Automation, Huaqiao University, Xiamen 361021, China
*
Author to whom correspondence should be addressed.
Micromachines 2025, 16(2), 184; https://doi.org/10.3390/mi16020184
Submission received: 9 January 2025 / Revised: 25 January 2025 / Accepted: 28 January 2025 / Published: 3 February 2025
(This article belongs to the Section E：Engineering and Technology)
Browse Figures
Versions Notes

Abstract

:
OH* generated through plasma catalysis offers several advantages, including a long survival time, high modification efficiency, and environmental friendliness. Consequently, a plasma-assisted polishing technology has rapidly developed. Previous studies exploring the interaction mechanism between OH* and 4H-SiC have often assumed flat surfaces. However, in the surface modification experiments on 4H-SiC, the actual surface morphology was not flat but contained numerous scratches. Therefore, this study investigated the interaction mechanism of OH* on an uneven surface using reactive force field molecular dynamics (ReaxFF MD) simulations. The results show that in the low-speed OH* modification process, the adsorption effect leads to a thicker modified layer at higher locations than at lower locations. The resulting modified layer can be removed by soft abrasive mechanical polishing to achieve surface flatness, but there will be a modified layer on the surface, which needs to be modified and polished several times. In contrast, during high-speed OH* modification, high-speed particle bombardment causes more Si-O bonds to diffuse into the scratches, resulting in the formation of a flat bonding layer with surface planarization achieved after a single polishing step. The interaction mechanism of OH* with the uneven surface at different speeds, as obtained through ReaxFF MD, provides a theoretical foundation for subsequent polishing experiments.
Keywords:
plasma; ReaxFF MD; 4H-SiC; OH*

1. Introduction

Currently, among more than 200 crystal types of silicon carbide (SiC), the most used include 3C-SiC, 4H-SiC, and 6H-SiC. Among these materials, 4H-SiC is notable, owing to its high electron mobility, superior breakdown field strength, enhanced thermal conductivity, and better lattice matching [1,2,3], which enable heterogeneous integration with other materials, such as gallium nitride (GaN). These outstanding characteristics make 4H-SiC ideal for a wide range of applications, including new energy vehicles, power transmission systems, and wireless communication technologies [4,5]. In these industrial applications, the 4H-SiC substrate has extremely high-quality requirements. Its total thickness deviation should not exceed 3 μm, the curvature and warpage should be within 25 μm, and its surface roughness must not surpass 0.5 nm. Moreover, the surface must be free of scratches and without any subsurface damage. These all fall into the realm of high-precision machining demands.
Although 4H-SiC offers numerous advantages, its high hardness and chemical inertness pose significant challenges to its processing. The processing of 4H-SiC wafers typically involves several stages, including slicing, grinding, and polishing [6,7,8]. As the final step in wafer processing, polishing is crucial for determining the quality of subsequent SiC device fabrication. Currently, chemical-mechanical polishing (CMP) is widely used to polish 4H-SiC wafers [9,10]. This process achieves surface flattening through a combination of the chemical reactions of chemical agents (KOH and KMnO₄) and mechanical removal by soft abrasives. However, the use of chemical agents complicates waste treatment and contributes to environmental pollution [11]. In contrast to chemical reagents such as strong acids and bases, OH*, the second most potent oxidizer (oxidation potential of 2.80 V) in nature after fluoride, reacts more readily with 4H-SiC, reducing its surface hardness. Consequently, OH* is widely [12,13,14] used in polishing 4H-SiC.
The main methods for polishing 4H-SiC using catalytically produced OH* include plasma-assisted polishing [15,16,17], photocatalysis [18,19], and the Fenton reaction [20,21,22]. In plasma-assisted polishing, OH* is generated by the ionization and excitation of water molecules by high-energy electrons. The 4H-SiC surface after OH* modification is softened, with its hardness lower than that of the original 4H-SiC. The modified layer is mechanically removed using a soft abrasive, resulting in a flattened surface. The OH* generated via plasma catalysis exists in gaseous form, which offers several advantages over the OH* produced in solution by photocatalysis or the Fenton reaction, such as longer survival time, higher modification efficiency, and a more environmentally friendly catalytic process, consequently leading to the rapid development of plasma-assisted polishing techniques. Yamamura et al. [23] employed a capacitively coupled discharge (CCP) to ionize helium (He) and water-mixed gas, which produced a plasma jet containing OH* that assisted in polishing 4H-SiC, achieving a surface roughness (Ra) value of 0.423 nm. Similarly, Deng et al. [24] obtained a smooth surface with a p-v of 1.889 nm and a root mean square (rms) value of 0.280 nm using plasma-catalyzed OH* polishing. Deng et al. [25] conducted a plasma modification rate experiment and compared it with the thermal oxidation rate at 1100 °C. The plasma modification rate was six times higher than that of thermal oxidation. The above experimental research on plasma-assisted polishing shows that plasma can modify SiC at a relatively high rate. In a previous study, we explored the interaction mechanism between OH* and 4H-SiC at the atomic scale using ReaxFF MD simulations [26]. During the OH* modification of 4H-SiC, C atoms leave the surface as gaseous compounds, leaving Si atoms to form Si-O bonds with O atoms, which reduces the surface hardness. After reducing the surface hardness, it can be mechanically polished by soft abrasive particles to achieve surface flatness. Free radicals produced by plasma-induced ionization were used to replace strong acids and bases in the process of chemical-mechanical polishing.
However, in our previous studies, the surface was assumed to be flat. Considering surfaces often contain numerous scratches, exploring the interaction mechanism between OH* and a scratched surface instead of a flat surface would offer more valuable insights into subsequent polishing experiments. In summary, this study investigated the mechanism of OH* interaction with an uneven 4H-SiC surface based on ReaxFF MD simulations, providing theoretical guidance for future polishing experiments.

2. Simulation

2.1. Deposition Velocity

Plasma is a collection of electrically neutral substances comprising electrons, ions, and neutral particles [27,28]. OH* is a neutral particle; its velocity is not influenced by the electric field. Typically, their velocities are determined by thermal motion and follow a Maxwell distribution function. Plasma can be categorized into high- and low-temperature types based on temperature [29,30,31]. Low-temperature plasmas can be further subdivided into hot (<10,000 K), warm (<3000 K), and cold plasmas (<1000 K). Different types of plasma exhibit varying temperatures. For instance, warm plasma is frequently employed in fields such as surface modification and film deposition, while cold plasma is often utilized in biomedicine, environmental protection, and surface modification owing to its low-temperature characteristics [32,33].
By taking the warm plasma temperature of 3000 K as an example, the OH* velocity distribution function is shown in Figure 1. The x axis is the velocity distribution of OH*, and the y axis is the probability of occurrence of pair velocity. When the OH* velocity exceeded the peak value, the probability of OH* appearing at the corresponding velocity decreased with increasing velocity. Currently, atmospheric pressure discharge is the most common form of plasma used in polishing processes. Under atmospheric pressure, the number density of OH* in plasma typically ranges from 1015 to 1017 m−3 [34]. The OH* velocity distribution under these conditions ranged from 0 to 10,000 m/s. The kinetic energies of OH* at 10 and 100 m/s are relatively small, and the number of particles at these velocities is low; thus, they are negligible. Although the number of high-speed OH* particles was small, their kinetic energy was significant, and their contributions could not be disregarded. Therefore, the deposition simulations were primarily conducted at three different speeds: 1000 m/s, 5500 m/s, and 10,000 m/s.

2.2. Simulation Model

A straight-edge scratch morphology was established on the surface via the pairwise removal of Si-C atoms. The simulation model is shown in Figure 2. The simulation process was described from three perspectives: bottom, side, and top. The model consisted of a deposition layer and a fixed layer. Periodic boundary conditions were applied in the X-and Y-directions, whereas the Z-direction was constrained by non-periodic and fixed boundary conditions. The elements involved in the potential function [35,36] are C, H, O, and Si. The size of the 4H-SiC model is 80 × 21 × 43 Å, containing 4956 particles. OH* radicals were randomly generated in the deposition layer and vertically deposited onto the 4H-SiC surface. The time step for the simulation was 0.25 fs, and 600,000 steps were executed. During plasma irradiation of 4H-SiC, in addition to the chemical interaction between OH* and the surface, inert gas particles physically bombard the surface, generating extremely high instantaneous temperatures. Therefore, setting the temperature of 4H-SiC to 2000 K simulates the effect of inert gas particles in generating high instantaneous temperatures and accelerates surface chemical reactions, allowing for better observation of the OH*-modified surface phenomena.

3. Simulation Result

3.1. The Deposition Results of OH* at Different Times When Deposited at 1000 m/s

The deposition results at different times and at a speed of 1000 m/s are shown in Figure 3. Specifically, for deposition times of 5 ps, 25 ps, 75 ps, and 150 ps, the corresponding numbers of running steps are 20,000, 100,000, 300,000, and 600,000, respectively.
At 5 ps, as shown in Figure 3a, the number of OH* deposited on the top surface is significantly greater than that deposited on the bottom surface. At 25 ps, as shown in Figure 3b, owing to the higher number of OH* groups at the top, the 4H-SiC surface at the top began to exhibit clear reactions, forming more Si-O bonds. In contrast, the number of OH* groups at the bottom was small, and only a few OH* groups reacted with the 4H-SiC surface. At 75 ps, as shown in Figure 3c, the top surface begins reacting with the third layer of 4H-SiC, whereas the bottom surface continues reacting with only the first layer. As the modified reaction progressed, the original straight-edge scratch began to show a slight bevel, and the Si-O bonds gradually diffused into the scratch.
At 150 ps, as shown in Figure 3d, the thickness of the modified layer at the top is 15 Å, while the thickness at the bottom is 7 Å. The modified layer at the top was thicker than that at the bottom. Owing to particle bombardment, the original straight-edged side of the scratch becomes inclined. The step thickness at the interface between the modified layer and the 4H-SiC surface was significantly reduced compared to that of the initial surface, facilitating subsequent mechanical removal.

3.2. The Deposition Results of OH* at Different Time When Deposited at 5500 m/s

The deposition results at different times and at a speed of 5500 m/s are shown in Figure 4.
At 5 ps, as shown in Figure 4a, the number of OH* molecules deposited at the bottom surface significantly increased compared to Figure 3a. At 25 ps, as shown in Figure 4b, the higher deposition speed resulted in more OH* entering the scratch. The number of OH* groups at the top and bottom was similar, resulting in a more uniform surface modification. At 75 ps, as shown in Figure 4c, with an increase in the deposition speed and kinetic energy, the number of Si-O bonds bombarded into the scratch also increased. Compared with Figure 3d, the surface exhibited an inclined edge 75 ps earlier.
At 150 ps, as shown in Figure 4d, the thickness of the modified layer within the scratch is 20 Å, while the thickness on both sides is 16 Å. The thickness of the modified layer at the bottom was greater than that on the sides, which is the opposite of the result obtained at 1000 m/s. During deposition, the modified layer within the scratch consists of the layer generated by the reaction between the deposited OH* and 4H-SiC and the layer formed by diffusion. Only the modified layer generated by the reaction between OH* and the 4H-SiC surface was present on both sides. Consequently, the modified layer within the scratch was thicker than that on the sides. However, at 1000 m/s, the step thickness between the modified layer and 4H-SiC remained similar to that of the initial surface and was significantly reduced.

3.3. The Deposition Results of OH* at Different Times When Deposited at 10,000 m/s

The deposition results at different times and at a speed of 10,000 m/s are shown in Figure 5.
At 5 ps, as shown in Figure 5a, owing to the increased velocity, no OH* offset was observed along the X and Y axes during the simulation. The higher velocity accelerates the reaction rate, and C atoms leave the surface as gaseous compounds. At 25 ps, as shown in Figure 5b, the deposition result is similar to that in Figure 4c; the straight-edge scratch becomes inclined, and the Si-O bonds diffuse into the scratch. At 75 ps, as shown in Figure 5c, the deposition result is similar to that shown in Figure 4d, with the thickness of the modified layer within the scratch being higher than that on both sides. The thickness of the modified layer within the scratch is 21 Å, while that on the sides is 15 Å.
At 150 ps, as shown in Figure 5d, a flat bonding layer formed between the modified layer and 4H-SiC. At 75 ps, the thickness of the modified layer on the scratch was greater than that on either side of the scratch. This increased thickness within the scratch led to a lower modification rate compared with that on the sides. Owing to the difference in the reaction rates, a dynamic equilibrium will eventually be reached between the two, and a flat bonding layer will form between the modified layer and 4H-SiC. During the simulation, C atoms aggregated to form carbon chains. This carbon chain formation phenomenon was also observed by Sun et al. [37] during oxidation of 3C-SiC.

3.4. Results of Different Speeds at an Inclined-Edge Scratch

In addition to straight-edge scratches, inclined-edge scratches may occur on the surface. Therefore, a simulation model for inclined-edge scratches was developed, as shown in Figure 6a. Simulations were performed at three different speeds, with the results shown in Figure 6b–d. The deposition result at 1000 m/s, as shown in Figure 6b, is similar to that of the scenario with a straight-edge scratch. The modified layer formed on both sides was thicker than that formed in the scratch, with some Si-O bonds diffusing into the scratch. When the deposition speed is increased to 5500 m/s, the result in Figure 6c indicates that the situation is similar to the straight-edge scratch case, with a thicker modified layer on the scratch than on the sides. At a deposition speed of 10,000 m/s, as shown in Figure 6d, a relatively flat modified layer was formed above the 4H-SiC, similar to the straight-edge scratch results. However, in the inclined-edge scratch, the number of C atoms increased, whereas the rate at which C atoms left the surface remained constant, leading to a higher number of carbon chains. Overall, the surface modification by OH* was not significantly affected by scratch morphology.

4. Discussion

During low-speed deposition, the OH* approach of 4H-SiC was influenced by chemical adsorption forces. Consequently, the OH* originally directed toward the bottom of the scratch alters its trajectory and is adsorbed on the sides or the top. The deposition process is shown in Figure 7a. Owing to the larger number of OH* groups on both sides, the thickness of the modified layer formed on the sides was greater than that in the scratch. As the deposition speed increased, the influence of the adsorption forces on the deposition direction of OH* decreased, as shown in Figure 7b. The minimum speed threshold required for OH* to reach the bottom is shown for different distances of OH* from the sides. However, as the speed increased, the bombardment effect of the particles accelerated the modification reaction and the diffusion rate of the Si-O bonds into the scratch, causing the modified layer in the scratch to become thicker than that on the sides during the process. At this point, the large thickness of the modified layer in the scratch limited the modification rate. As the reaction progressed, a flat modified layer formed.
Based on the above simulations and the varying morphologies of the modified layer obtained at different deposition speeds, two distinct polishing mechanisms are proposed: high-speed OH* and low-speed OH*. The first mechanism is low-speed OH*, with the interaction mechanism between the low-speed OH* and 4H-SiC illustrated in Figure 8. The irradiated surfaces are also irregular. Owing to the influence of the adsorption forces, the thickness of the modified layer formed on the sides was greater than that formed in the scratch. Through nano-indentation tests, we previously demonstrated [26] that the hardness of the modified layer was lower than that of unmodified 4H-SiC. After plasma modification, a surface without subsurface damage can be obtained by the mechanical removal of soft abrasive particles without strong acid or alkali reagents; however, a small amount of the modified layer remains on the surface. At this point, a second plasma irradiation step was applied. The modified layer formed in the scratch during the first plasma exposure limited the modification rate, causing the modification rate in the scratch to be lower than that on the sides. This difference in the modification rate led to the eventual formation of a flat modified layer across the surface. Subsequent mechanical removal using a soft abrasive resulted in a flat surface without any residual modified layer. The number of cycles required depended on the thickness of each modification and the scratch depth.
The polishing mechanism between the high-speed OH* and the surface is illustrated in Figure 9. This interaction is relatively complex and can be divided into three stages. In the first stage, owing to the high-speed movement of OH*, the influence of the adsorption force decreased during deposition, resulting in the formation of a uniform modification layer on the surface. In the second stage, the reaction continues, and the modified layer in the scratch is composed of OH* deposited through its reaction with 4H-SiC and Si-O bonds that diffuse into the scratch due to particle bombardment. Consequently, the modified layer at the bottom was thicker than that at the top. In the third stage, the increased thickness of the modified layer at the bottom limits the modification rate. Therefore, the modification rate at the top is higher than that at the bottom. As the reaction progressed, the modification rates at both the top and bottom eventually reached a dynamic equilibrium, leading to the formation of a flat modified layer across the surface. After the flat modified layer was formed, it was removed by soft abrasive polishing, resulting in a smooth, flattened surface.

5. Conclusions

In this paper, the mechanism of OH* deposition at different speeds on 4H-SiC surfaces with varying morphologies using ReaxFF MD is analyzed. The following conclusions were drawn:
1. During low-speed deposition, owing to surface adsorption, the modified layer formed at the top was larger than that formed at the bottom. Surface flattening can be achieved by modifying the polishing cycles.
2. During high-speed deposition, an increase in speed reduces surface adsorption; however, high-speed deposition accelerates the diffusion of Si-O bonds into the scratch, causing a difference in the modification rates between the bottom and top. Finally, a flat bonding layer was formed on the surface; this layer was flattened using a single polishing step.
3. When the OH* modified the 4H-SiC surface, two different scratch morphologies could obtain a similar, modified layer, indicating that the surface morphology had little effect on the modification result.

Author Contributions

Conceptualization, D.Y. and N.D.; methodology, D.Y.; software, D.Y.; validation, D.Y., H.H., M.X. and N.D.; formal analysis, D.Y.; investigation, D.Y.; resources, H.H. and N.D.; data curation, D.Y.; writing—original draft preparation, D.Y. and M.X.; writing—review and editing, D.Y.; visualization, D.Y.; supervision, H.H. and N.D.; project administration, H.H and N.D.; funding acquisition, H.H. and N.D. All authors have read and agreed to the published version of the manuscript.

Funding

This work has been partially funded by the National Natural Science Foundation of China (U22A20198), the Changjiang Scholars and Innovative Research Team in University (IRT_17R41) and the 111 Project of China (Grant No. B23011), the National Natural Science Foundation of China (Grant No. 52375427), and the Natural Science Foundation General Project in Fujian Province (Grant No. 2022J01299).

Data Availability Statement

Data will be made available on request.

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

  1. Wang, P.R.; Liu, F.Q.; Wang, H.; Li, H.; Gou, Y.Z. A review of third generation SiC fibers and SiCf/SiC composites. J. Mater. Sci. Technol. 2019, 35, 2743–2750. [Google Scholar] [CrossRef]
  2. Chen, S.L.; Li, W.J.; Li, X.X.; Yang, W.Y. One-dimensional SiC nanostructures: Designed growth, properties, and applications. Prog. Mater. Sci. 2019, 104, 138–214. [Google Scholar] [CrossRef]
  3. Wu, R.B.; Zhou, K.; Yue, C.Y.; Wei, J.; Pan, Y. Recent progress in synthesis, properties and potential applications of SiC nanomaterials. Prog. Mater. Sci. 2015, 72, 1–60. [Google Scholar] [CrossRef]
  4. DiMarino, C.; Wang, J.; Burgos, R.; Boroyevich, D. A high-power-density, high-speed gate driver for a 10 kV SiC MOSFET module. In Proceedings of the 2017 IEEE Electric Ship Technologies Symposium (ESTS), Arlington, VA, USA, 14–17 August 2017; pp. 629–634. [Google Scholar] [CrossRef]
  5. Lee, H.; Smet, V.; Tummala, R. A Review of SiC Power Module Packaging Technologies: Challenges, Advances, and Emerging Issues. IEEE J. Emerg. Sel. Top. Power Electron. 2020, 8, 239–255. [Google Scholar] [CrossRef]
  6. Gao, Y.F.; Chen, Y. Sawing stress of SiC single crystal with void defect in diamond wire saw slicing. Int. J. Adv. Manuf. Technol. 2019, 103, 1019–1031. [Google Scholar] [CrossRef]
  7. Liu, J.T.; Kang, R.K.; Dong, Z.G.; Zheng, F.F.; Zeng, Y.F.; Bao, Y. Experimental investigation of damage formation and material removal in ultrasonic assisted grinding of RBSiC. Mater. Res. Express 2020, 7, 125202. [Google Scholar] [CrossRef]
  8. Lai, Z.; Huang, H.; Hu, Z.; Liao, X. Dynamic model and machining mechanism of wire sawing. J. Mater. Process Technol. 2023, 311, 117820. [Google Scholar] [CrossRef]
  9. Wang, W.; Lu, X.; Wu, X.; Zhang, Y.; Wang, R.; Yang, D.; Pi, X. Chemical-Mechanical Polishing of 4H Silicon Carbide Wafers. Adv. Mater. Interfaces 2023, 10, 2202369. [Google Scholar] [CrossRef]
  10. Hsieh, C.-H.; Chang, C.-Y.; Hsiao, Y.-K.; Chen, C.-C.A.; Tu, C.-C.; Kuo, H.-C. Recent Advances In Silicon Carbide Chemical Mechanical Polishing Technologies. Micromachines 2022, 13, 1752. [Google Scholar] [CrossRef] [PubMed]
  11. Ji, J.W.; Yamamura, K.; Deng, H. Plasma-assisted polishing for atomic surface fabrication of single crystal SiC. Acta Phys. Sin. 2021, 70. [Google Scholar] [CrossRef]
  12. Kawaguchi, K.; Wang, Y.; Xu, J.; Ootani, Y.; Higuchi, Y.; Ozawa, N.; Kubo, M. Cooperative roles of chemical reactions and mechanical friction in chemical mechanical polishing of gallium nitride assisted by OH radicals: Tight-binding quantum chemical molecular dynamics simulations. Phys. Chem. Chem. Phys. 2021, 23, 4075–4084. [Google Scholar] [CrossRef] [PubMed]
  13. Yuan, Z.W.; Tang, M.L.; Wang, Y.; Sun, J.T.; He, Y. Atomistic removal mechanisms of nano polishing single-crystal SiC in hydroxyl free radical aqueous solution. Phys. Scr. 2023, 98, 085404. [Google Scholar] [CrossRef]
  14. Sun, R.; Kinoshita, R.; Aoki, K.; Hayakawa, S.; Hori, K.; Yasuda, K.; Ohkubo, Y.; Yamamura, K. Oxidation mechanism of 4H-SiC in slurry-less ECMP with weak alkaline electrolyte. CIRP Ann.-Manuf. Technol. 2024, 73, 277–280. [Google Scholar] [CrossRef]
  15. Deng, H.; Endo, K.; Yamamura, K. Damage-free finishing of CVD-SiC by a combination of dry plasma etching and plasma-assisted polishing. Int. J. Mach. Tools Manuf. 2017, 115, 38–46. [Google Scholar] [CrossRef]
  16. Deng, H.; Ueda, M.; Yamamura, K. Characterization of 4H-SiC (0001) surface processed by plasma-assisted polishing. Int. J. Adv. Manuf. Technol. 2014, 72, 1–7. [Google Scholar] [CrossRef]
  17. Shen, X.; Tu, Q.; Deng, H.; Jiang, G.; Yamamura, K. Mechanism analysis on finishing of reaction-sintered silicon carbide by combination of water vapor plasma oxidation and ceria slurry polishing. Opt. Eng. 2015, 54, 055106. [Google Scholar] [CrossRef]
  18. He, Y.; Yuan, Z.; Tang, M.; Sun, J.; Liu, C.; Gao, X. Mechanism of chemical and mechanical mutual promotion in photocatalysis-assisted chemical mechanical polishing for single-crystal SiC. Proc. Inst. Mech. Eng. Part C-J. Mech. Eng. Sci. 2022, 236, 11464–11478. [Google Scholar] [CrossRef]
  19. Yan, Q.; Wang, X.; Xiong, Q.; Lu, J.; Liao, B. The influences of technological parameters on the ultraviolet photocatalytic reaction rate and photocatalysis-assisted polishing effect for SiC. J. Cryst. Growth 2020, 531, 125379. [Google Scholar] [CrossRef]
  20. Deng, J.Y.; Pan, J.S.; Zhang, Q.X.; Yan, Q.S.; Lu, J.B. The mechanism of Fenton reaction of hydrogen peroxide with single crystal 6H-SiC substrate. Surf. Interfaces 2020, 21, 100730. [Google Scholar] [CrossRef]
  21. Lu, J.B.; Chen, R.; Liang, H.Z.; Yan, Q.S. The influence of concentration of hydroxyl radical on the chemical mechanical polishing of SiC wafer based on the Fenton reaction. Precis. Eng.-J. Int. Soc. Precis. Eng. Nanotechnol. 2018, 52, 221–226. [Google Scholar] [CrossRef]
  22. Hu, D.; Li, H.; Lu, J.; Yan, Q.; Xiong, Q.; Huang, Z.; Zhang, F. Study on heterogeneous Fenton reaction parameters for pol-ishing single-crystal SiC using magnetorheological elastomers polishing pads. Smart Mater. Struct. 2023, 32, 025003. [Google Scholar] [CrossRef]
  23. Yamamura, K.; Takiguchi, T.; Ueda, M.; Deng, H.; Hattori, A.N.; Zettsu, N. Plasma assisted polishing of single crystal SiC for obtaining atomically flat strain-free surface. CIRP Ann. 2011, 60, 571–574. [Google Scholar] [CrossRef]
  24. Deng, H.; Takiguchi, T.; Ueda, M.; Hattori, A.N.; Zettsu, N.; Yamamura, K. Damage-Free Dry Polishing of 4H-SiC Combined with Atmospheric-Pressure Water Vapor Plasma Oxidation. Jpn. J. Appl. Phys. 2011, 50, 08JG05. [Google Scholar] [CrossRef]
  25. Deng, H.; Endo, K.; Yamamura, K. Comparison of thermal oxidation and plasma oxidation of 4H-SiC (0001) for surface flattening. Appl. Phys. Lett. 2014, 104, 101608. [Google Scholar] [CrossRef]
  26. Yan, D.; Huang, H.; Huang, Y.; Yang, H.; Duan, N. Study on OH radical oxidation of 4H-SiC in plasma based on ReaxFF molecular dynamics simulation. J. Mol. Liq. 2024, 400, 124573. [Google Scholar] [CrossRef]
  27. Bruggeman, P.J.; Iza, F.; Brandenburg, R. Foundations of atmospheric pressure non-equilibrium plasmas. Plasma Sources Sci. Technol. 2017, 26, 123002. [Google Scholar] [CrossRef]
  28. Pelletier, J.; Anders, A. Plasma-blased ion implantation and deposition: A review of physics, technology, and applications. IEEE Trans. Plasma Sci. 2005, 33, 1944–1959. [Google Scholar] [CrossRef]
  29. Liu, J.Y.; Li, Y.H.; Chen, Y.; Zhou, Y.Y.; Wang, S.S.; Yuan, Z.Z.; Jin, Z.J.; Liu, X. A review of low-temperature plasma-assisted machining: From mechanism to application. Front. Mech. Eng. 2023, 18, 18. [Google Scholar] [CrossRef]
  30. Dowling, D.P.; Stallard, C.P. Achieving enhanced material finishing using cold plasma treatments. Trans. Inst. Met. Finish. 2015, 93, 119–125. [Google Scholar] [CrossRef]
  31. Kambara, M.; Kawaguchi, S.; Lee, H.J.; Ikuse, K.; Hamaguchi, S.; Ohmori, T.; Ishikawa, K. Science-based, data-driven developments in plasma processing for material synthesis and device-integration technologies. Jpn. J. Appl. Phys. 2023, 62, SA0803. [Google Scholar] [CrossRef]
  32. Bonizzoni, G.; Vassallo, E. Plasma physics and technology; industrial applications. Vacuum 2002, 64, 327–336. [Google Scholar] [CrossRef]
  33. Reuter, S.; von Woedtke, T.; Weltmann, K.-D. The kINPen-a review on physics and chemistry of the atmospheric pressure plasma jet and its applications. J. Phys. D-Appl. Phys. 2018, 51, 233001. [Google Scholar] [CrossRef]
  34. Liu, Y.; Tan, Z.; Chen, X.; Li, X.; Wang, X. A Numerical Investigation on the Effects of Water Vapor on Electron Energy and OH Production in Atmospheric-Pressure He/H2O and Ar/H2O Plasma Jets. IEEE Trans. Plasma Sci. 2019, 47, 1593–1604. [Google Scholar] [CrossRef]
  35. Newsome, D.A.; Sengupta, D.; van Duin, A.C.T. High-Temperature Oxidation of SiC-Based Composite: Rate Constant Calculation from ReaxFF MD Simulations, Part II. J. Phys. Chem. C 2013, 117, 5014–5027. [Google Scholar] [CrossRef]
  36. Newsome, D.A.; Sengupta, D.; Foroutan, H.; Russo, M.F.; van Duin, A.C.T. Oxidation of Silicon Carbide by O2 and H2O: A ReaxFF Reactive Molecular Dynamics Study, Part I. J. Phys. Chem. C 2012, 116, 16111–16121. [Google Scholar] [CrossRef]
  37. Sun, Y.; Liu, Y.-J.; Xu, F. ReaxFF molecular dynamics study on oxidation behavior of 3C-SiC: Polar face effects. Chin. Phys. B 2015, 24, 096203. [Google Scholar] [CrossRef]
Micromachines 16 00184 g001
Figure 1. Thermal motion distribution function of OH* at 3000 K.
Figure 1. Thermal motion distribution function of OH* at 3000 K.
Micromachines 16 00184 g001
Micromachines 16 00184 g002
Figure 2. Schematic diagram of the simulation model.
Figure 2. Schematic diagram of the simulation model.
Micromachines 16 00184 g002
Micromachines 16 00184 g003
Figure 3. Results at different times of deposition at 1000 m/s. (a) 5 ps; (b) 25 ps; (c) 75 ps; (d) 150 ps.
Figure 3. Results at different times of deposition at 1000 m/s. (a) 5 ps; (b) 25 ps; (c) 75 ps; (d) 150 ps.
Micromachines 16 00184 g003
Micromachines 16 00184 g004
Figure 4. Results at different times of deposition at 5500 m/s. (a) 5 ps; (b) 25 ps; (c) 75 ps; (d) 150 ps.
Figure 4. Results at different times of deposition at 5500 m/s. (a) 5 ps; (b) 25 ps; (c) 75 ps; (d) 150 ps.
Micromachines 16 00184 g004
Micromachines 16 00184 g005
Figure 5. Results at different times of deposition at 10,000 m/s. (a) 10 ps; (b) 25 ps; (c) 75 ps; (d) 150 ps.
Figure 5. Results at different times of deposition at 10,000 m/s. (a) 10 ps; (b) 25 ps; (c) 75 ps; (d) 150 ps.
Micromachines 16 00184 g005
Micromachines 16 00184 g006
Figure 6. Result for an inclined-edge scratch. (a) Initial model; (b) 1000 m/s; (c) 5500 m/s; (d) 10,000 m/s
Figure 6. Result for an inclined-edge scratch. (a) Initial model; (b) 1000 m/s; (c) 5500 m/s; (d) 10,000 m/s
Micromachines 16 00184 g006
Micromachines 16 00184 g007
Figure 7. The details of the adsorption process: (a) the movement trajectory of OH*; (b) speed threshold at different distances.
Figure 7. The details of the adsorption process: (a) the movement trajectory of OH*; (b) speed threshold at different distances.
Micromachines 16 00184 g007
Micromachines 16 00184 g008
Figure 8. Polishing mechanism at low speed.
Figure 8. Polishing mechanism at low speed.
Micromachines 16 00184 g008
Micromachines 16 00184 g009
Figure 9. Polishing mechanism at high speed.
Figure 9. Polishing mechanism at high speed.
Micromachines 16 00184 g009
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Yan, D.; Huang, H.; Xue, M.; Duan, N. Mechanism of OH*-Modified 4H-SiC Surface with Scratches Based on ReaxFF MD Simulation. Micromachines 2025, 16, 184. https://doi.org/10.3390/mi16020184

AMA Style

Yan D, Huang H, Xue M, Duan N. Mechanism of OH*-Modified 4H-SiC Surface with Scratches Based on ReaxFF MD Simulation. Micromachines. 2025; 16(2):184. https://doi.org/10.3390/mi16020184

Chicago/Turabian Style

Yan, Dongxiao, Hui Huang, Mingpu Xue, and Nian Duan. 2025. "Mechanism of OH*-Modified 4H-SiC Surface with Scratches Based on ReaxFF MD Simulation" Micromachines 16, no. 2: 184. https://doi.org/10.3390/mi16020184

APA Style

Yan, D., Huang, H., Xue, M., & Duan, N. (2025). Mechanism of OH*-Modified 4H-SiC Surface with Scratches Based on ReaxFF MD Simulation. Micromachines, 16(2), 184. https://doi.org/10.3390/mi16020184

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Article metric data becomes available approximately 24 hours after publication online.
Back to TopTop