高质量大尺寸单晶金刚石的亚纳米表面抛光工艺研究

江名鑫; 刘朝平; 王跃忠; 李赫; 江南; 西村一仁; 黎清宁; 袁其龙; 杨明阳

doi:10.16490/j.cnki.issn.1001-3660.2026.07.003

PDF(6279 KB)

表面技术 ›› 2026, Vol. 55 ›› Issue (7) : 27-34. DOI: 10.16490/j.cnki.issn.1001-3660.2026.07.003

精密与超精密加工

高质量大尺寸单晶金刚石的亚纳米表面抛光工艺研究

江名鑫^1,2,3, 刘朝平^1,2,4, 王跃忠^1,2, 李赫^1,2, 江南^1,2, 西村一仁^1,2, 黎清宁³, 袁其龙^1,2,*, 杨明阳^1,2,*

作者信息 +

Sub-nanometer Surface Polishing Process for High-quality Large-size Single-crystal Diamonds

JIANG Mingxin^1,2,3, LIU Chaoping^1,2,4, WANG Yuezhong^1,2, LI He^1,2, JIANG Nan^1,2, KAZUHITO Nishimura^1,2, LI Qingning³, YUAN Qilong^1,2,*, YANG Mingyang^1,2,*

Author information +

文章历史 +

摘要

目的针对大尺寸单晶金刚石表面加工质量难的问题,本研究采用外延生长结合抛光工艺,探讨抛光液组分和抛光时间对英寸级单晶金刚石表面形貌及粗糙度的影响,旨在实现亚纳米级加工表面。方法通过微波等离子体化学气相沉积法（MPCVD）制备英寸级单晶金刚石,利用共聚焦拉曼光谱（Raman）和高分辨X射线衍射（HRXRD）表征晶体质量。采用紫外光辅助化学机械抛光法（UV-CMP）,分别在含Fenton试剂、H₂O₂和仅含H₂O₂的抛光液下抛光。通过原子力显微镜（AFM）分析表面粗糙度和材料去除率,并利用傅里叶变换红外光谱仪（FTIR）测试抛光前后的红外光学透过率。结果通过400 h生长获得了尺寸为17 mm×17 mm×1.2 mm的高质量单晶金刚石,拉曼峰半高宽低至2.16 cm^‒1;UV-CMP结果显示,含Fenton试剂的抛光液的Fe²⁺催化产生的羟基自由基（∙OH）生成速率过快,与金刚石表面碳原子去除速率不匹配,不利于表面平滑化,而单一H₂O₂抛光液则可实现粗糙度低至0.40 nm的亚纳米级光滑表面。红外透过率测试揭示了金刚石在10.6 µm处的平均红外透过率由68.8%提升到72.4%。结论采用MPCVD法获得英寸级高质量单晶金刚石,通过抛光液组分调控金刚石抛光后的表面粗糙度,进而提升其红外光学透过率,该工作为大尺寸单晶金刚石的高质量表面加工及应用提供了工艺参考。

Abstract

The large single-crystal diamond with high surface quality is a key material for advanced applications such as deep-UV optoelectronic devices, high-power laser windows, heat-dissipation substrates, and quantum technologies. However, its extreme hardness and high chemical stability make it challenging to achieve ultra-smooth, sub-nanometer-level surfaces without inducing subsurface damage. Traditional mechanical polishing inevitably introduces deep subsurface damage such as microcracks and dislocations, severely compromising device performance and reliability. Meanwhile, non-contact techniques like plasma etching, while avoiding mechanical damage, struggle to simultaneously achieve exceptional surface flatness and atomic-level roughness requirements across large dimensions. These process bottlenecks significantly hinder the industrial-scale mass production of inch-sized single-crystal diamond wafers. To overcome this bottleneck, the work aims to develop an integrated approach that combines microwave plasma chemical vapor deposition (MPCVD) with ultraviolet-assisted chemical mechanical polishing (UV-CMP), so as to realize sub-nanometer flat surface of the inch-scale single-crystal diamond. The high-quality single-crystal diamond with a size of 17 mm × 17 mm and a thickness of 1.2 mm was grown by MPCVD for 400 h. Raman spectroscopy and high-resolution X-ray diffraction (HRXRD) confirmed its excellent crystalline quality, with a Raman peak full width at half maxima (FWHM) of 2.16 cm^-1 and a (004) diffraction FWHM of 90.75 arcsec (1 arcsec=(1/3 600)°), indicating low dislocation density and high lattice integrity. Subsequently, UV-CMP experiments were carried out with two types of SiO₂-based slurries: one containing Fenton's reagent (Fe²⁺/H₂O₂) and another containing only H₂O₂. The effect of slurry composition and UV irradiation on the polishing rate and surface morphology was systematically investigated. The Fe²⁺-containing slurry produced large amounts of hydroxyl radicals (·OH) under UV illumination but suffered from rapid Fe²⁺ depletion, leading to a mismatch between oxidation and material removal rates. This imbalance caused unstable polishing and limited surface roughness improvement. In contrast, the Fe²⁺-free slurry maintained continuous hydroxyl radicals (·OH) generation through photoactivation of H₂O₂ under 365 nm UV light, ensuring a stable chemical-mechanical interaction. The sustained oxidation and gentle removal of surface carbon atoms established a balanced mechanism of "oxidation-softening-removal", enabling uniform polishing while avoiding subsurface damage. Atomic force microscopy (AFM) measurements revealed that after UV-CMP with the Fe²⁺-free slurry, the root-mean-square (RMS) surface roughness decreased to 0.40 nm within a 20 μm × 20 μm scan area, reaching sub-nanometer ultra-smoothness. Fourier transform infrared (FTIR) spectroscopy showed that the average infrared transmittance at 10.6 μm increased from 68.8% to 72.4% after polishing, approaching the intrinsic transmittance of type IIa diamond (72.7%). The enhancement of optical transmittance was attributed to the significant reduction in surface roughness scattering and the preservation of high crystalline integrity during polishing. In summary, this study demonstrates that the combination of MPCVD epitaxial growth and UV-assisted CMP provides an effective route for achieving high-quality, ultra-smooth surfaces on inch-scale single-crystal diamond. The optimized Fe²⁺-free slurry enables sustainable radical generation, high polishing efficiency, and superior optical performance. This approach offers a practical and scalable solution for surface planarization and optical enhancement of the large single-crystal diamond, supporting its future applications in high-power laser systems, DUV photonic chips, and quantum thermal management devices.

导出引用

江名鑫, 刘朝平, 王跃忠, 李赫, 江南, 西村一仁, 黎清宁, 袁其龙, 杨明阳. 高质量大尺寸单晶金刚石的亚纳米表面抛光工艺研究[J]. 表面技术. 2026, 55(7): 27-34

JIANG Mingxin, LIU Chaoping, WANG Yuezhong, LI He, JIANG Nan, KAZUHITO Nishimura, LI Qingning, YUAN Qilong, YANG Mingyang. Sub-nanometer Surface Polishing Process for High-quality Large-size Single-crystal Diamonds[J]. Surface Technology. 2026, 55(7): 27-34

中图分类号： TG356.28

参考文献

[1] JIA L M, CHENG L, ZHENG W.8-nm Narrowband Photodetection in Diamonds[J]. Opto-Electronic Science, 2023, 2(7): 230010.
[2] SHI X Q, YANG Z M, YIN S C, et al.Al Plasmon- Enhanced Diamond Solar-Blind UV Photodetector by Coupling of Plasmon and Excitons[J]. Materials Technology, 2016, 31(9): 544-547.
[3] CHEN C K, ZHANG Y Z, YEH C R, et al.CH₄/(Ar-H₂) Plasma Post-Treatments Produce Nano-Diamond Aggregation and Improvement in Field Emission Properties of Ultrananocrystalline Diamond Films[J]. Applied Physics A, 2023, 130(1): 47.
[4] SERPENTE V, BELLUCCI A, GIROLAMI M, et al.Combined Electrical Resistivity-Electron Reflectivity Measurements for Evaluating the Homogeneity of Hydrogen-Terminated Diamond Surfaces[J]. Diamond and Related Materials, 2021, 114: 108290.
[5] LIAO M Y, SANG L W, TERAJI T, et al.Comprehensive Investigation of Single Crystal Diamond Deep-Ultraviolet Detectors[J]. Japanese Journal of Applied Physics, 2012, 51(9R): 090115.
[6] LI F N, ZHANG J W, WANG X L, et al.Deep-Ultraviolet Detectors Based on Oxygen-/Fluorine-Terminated (100) Diamond[J]. Superlattices and Microstructures, 2016, 100: 258-265.
[7] REED B P, BATHEN M E, ASH J W R, et al. Diamond (111) Surface Reconstruction and Epitaxial Graphene Interface[J]. Physical Review B, 2022, 105(20): 205304.
[8] TAQY S, SARKAR P, HAMID M A, et al.Diamond Deposition on AlN Using Q-Carbon Interlayer through Overcoming the Substrate Limitations[J]. Carbon, 2024, 219: 118809.
[9] REN Z Y, ZHANG J F, ZHANG J C, et al.Growth and Characterization of the Laterally Enlarged Single Crystal Diamond Grown by Microwave Plasma Chemical Vapor Deposition[J]. Chinese Physics Letters, 2018, 35(7): 078101.
[10] KUBOTA A, NAGAE S, MOTOYAMA S.High-Precision Mechanical Polishing Method for Diamond Substrate Using Micron-Sized Diamond Abrasive Grains[J]. Diamond and Related Materials, 2020, 101: 107644.
[11] LI F N, BAO H W, LI Y, et al.Laser Induced Diamond/Graphite Structure for All-Carbon Deep-Ultraviolet Photodetector[J]. Applied Surface Science, 2023, 636: 157818.
[12] WANG X Y, WANG Y D, YANG B R, et al.Morphology-Controllable Liquid Metal/Diamond Sandwich- Structured Thermal Interface Material Toward High- Efficiency Thermal Management[J]. ACS Nano, 2025, 19(22): 20956-20969.
[13] 王艳丰, 王宏兴. MPCVD单晶金刚石生长及其电子器件研究进展[J]. 人工晶体学报, 2020, 49(11): 2139-2152.
WANG Y F, WANG H X.Research Progress of MPCVD Single Crystal Diamond Growth and Diamond Electronic Devices[J]. Journal of Synthetic Crystals, 2020, 49(11): 2139-2152.
[14] REN Z Y, LIU J, SU K, et al.Multiple Enlarged Growth of Single Crystal Diamond by MPCVD with PCD-Rimless Top Surface[J]. Chinese Physics B, 2019, 28(12): 128103.
[15] HARDY A, MUEHLE M, HERRERA-RODRIGUEZ C, et al.Chemical Mechanical Polishing of Single-Crystalline Diamond Epitaxial Layers for Electronics Applications[J]. IEEE Transactions on Semiconductor Manufacturing, 2024, 37(2): 190-198.
[16] ZHENG Y T, CUMONT A E L, BAI M J, et al. Smoothing of Single Crystal Diamond by High-Speed Three-Dimensional Dynamic Friction Polishing: Optimization and Surface Bonds Evolution Mechanism[J]. International Journal of Refractory Metals and Hard Materials, 2021, 96: 105472.
[17] ZHAO L, WANG X B, JIANG M X, et al.Optimization of Diamond Polishing Process for Sub-Nanometer Roughness Using Ar/O₂/SF₆ Plasma[J]. Materials, 2025, 18(11): 2615.
[18] HUANG W L, LI H L, LU J B, et al.Experimental Study on UV Photocatalytic Assisted Chemical Mechanical Polishing Process for Single-Crystal Diamond[J]. Diamond and Related Materials, 2025, 159: 112771.
[19] LIAO L X, ZHANG Z Y, MENG F N, et al.A Novel Slurry for Chemical Mechanical Polishing of Single Crystal Diamond[J]. Applied Surface Science, 2021, 564: 150431.
[20] FEI H Z, SANG D D, ZOU L R, et al.Research Progress of Optoelectronic Devices Based on Diamond Materials[J]. Frontiers in Physics, 2023, 11: 1226374.
[21] ZHU Y H, ZHU Z G, CHEN C K, et al.Preparation of Nanodiamonds Based on Phase Transformation of Vertical Sheet under Atmospheric Pressure[J]. Acta Physica Sinica, 2024, 73(2): 028101.
[22] IMURA M, LIAO M Y, ALVAREZ J, et al.Schottky-Barrier Photodiode Using P-Diamond Epilayer Grown on P+-Diamond Substrates[J]. Diamond and Related Materials, 2009, 18(2/3): 296-298.
[23] INYUSHKIN A V, TALDENKOV A N, YELISSEYEV A P, et al.Thermal Conductivity of Type-Ib HPHT Synthetic Diamond Irradiated with Electrons[J]. Diamond and Related Materials, 2023, 139: 110302.
[24] LIU W T, XIONG Q, LU J B, et al.Tribological Behavior of Single Crystal Diamond Based on UV Photocatalytic Reaction[J]. Tribology International, 2022, 175: 107806.