Uniform Growth of Two-inch MPCVD Optical Grade Diamond Film

At a Glance

Metadata	Details
Publication Date	2023-01-01
Journal	Journal of Inorganic Materials
Authors	S Y Chan, Juping Tu, Ke Huang, Siwu SHAO, Zhiliang Yang
Institutions	University of Science and Technology Beijing, North China University of Technology
Citations	3
Analysis	Full AI Review Included

Technical Documentation & Analysis: Uniform Growth of Two-inch MPCVD Optical Grade Diamond Film

This analysis leverages the findings of the research paper to highlight 6CCVD’s superior capabilities in manufacturing high-quality, large-area MPCVD diamond materials for advanced engineering and scientific applications.

Executive Summary

This study successfully demonstrates the uniform growth of large-area optical grade polycrystalline diamond (PCD) films, a critical requirement for high-power optical windows and fusion applications.

Material Achievement: Uniform fabrication of 2-inch (50.8 mm diameter) optical grade PCD films using a 2.45 GHz, 6 kW MPCVD system.
Process Optimization: Uniformity was achieved by optimizing the deposition platform height (2 mm) based on coupled COMSOL simulation and experimental validation.
Thickness & Uniformity: Films reached a maximum thickness of 337 µm with excellent thickness non-uniformity measured at <11.0%.
Optical Performance: High transmission confirmed, with peak visible light transmission (480-800 nm) exceeding 60% and infrared transmission at 10.6 µm reaching up to 70.1%.
Quality Metrics: High crystalline quality confirmed by low Raman FWHM (3.27 cm⁻¹ at the center) and a strong (220) preferential growth orientation.
Mechanism Insight: Increasing the platform height improved electric field uniformity, flattened the plasma shape, and increased the concentration of active H and carbon-containing radicals (CH, C₂) near the substrate surface.

Technical Specifications

The following hard data points were extracted from the research paper detailing the material properties and optimized process parameters.

Parameter	Value	Unit	Context
Substrate Diameter	2 (50.8)	inch (mm)	Large Area Growth Target
Maximum Thickness	337	µm	Achieved at optimal 2 mm height
Thickness Non-Uniformity	<11.0	%	Across 2-inch wafer
Growth Rate	1.5	µm/h	Calculated average rate
Optimal Platform Height	2	mm	Optimized for uniformity
MPCVD Frequency	2.45	GHz	Microwave source frequency
MPCVD Power	6	kW	Maximum system power
Visible Transmission (Peak)	69.8	%	480-800 nm range
IR Transmission (10.6 µm)	70.1	%	Center measurement
Raman FWHM (Center)	3.27	cm⁻¹	Indicator of crystal quality
XRD Orientation Ratio	76.62	N/A	S₍₂₂₀₎/S₍₁₁₁₎, strong (220) preference
Temperature Uniformity (ΔT)	21	°C	Temperature difference across the substrate at 2 mm height

Key Methodologies

The uniform growth of the optical grade diamond film was achieved through a highly controlled MPCVD process combined with advanced simulation and characterization techniques.

Simulation & Optimization: COMSOL software was used to simulate the effect of deposition platform height (ranging from -2 mm to 2 mm) on electric field distribution, plasma shape, and temperature uniformity.
Reactor Setup: A 2.45 GHz, 6 kW MPCVD system was utilized, employing a cylindrical cavity design.
Substrate Preparation: 2-inch Si (100) wafers were used as substrates, prepared via mechanical polishing and ultrasonic cleaning in diamond powder solution for enhanced nucleation density.
Nucleation Phase (4 h):
- Power: 4.7 kW
- Pressure: 35 kPa
- Gas Flow (H₂/CH₄): 35/500 (sccm, implied)
- Temperature: 880 °C
Growth Phase (200 h):
- Power: 4.7-4.9 kW
- Pressure: 21-22 kPa
- Gas Flow (H₂/CH₄/O₂): 21-22/5/500 (sccm, implied)
- Temperature: 870-880 °C
Characterization: Material quality was assessed using X-ray Diffraction (XRD), Raman spectroscopy, Optical Emission Spectroscopy (OES) for plasma diagnostics, and UV-Vis-NIR/IR transmission spectroscopy.

6CCVD Solutions & Capabilities

This research validates the critical need for precise MPCVD control, large-area capability, and high-quality optical finishing—all core strengths of 6CCVD. We are uniquely positioned to replicate, scale, and extend this research for industrial and scientific clients.

Requirement from Paper	6CCVD Solution & Capability	Technical Advantage
Applicable Materials	Optical Grade Polycrystalline Diamond (PCD)	High purity, low absorption, ideal for high-power optical windows and thermal management applications.
Large Area Scaling	Custom Plates/Wafers up to 125 mm diameter (PCD)	6CCVD exceeds the 2-inch (50.8 mm) diameter demonstrated, enabling next-generation scaling for larger fusion or industrial optics.
Thick Film Capability	PCD thickness range: 0.1 µm to 500 µm	We guarantee the ability to meet or exceed the 337 µm thickness achieved, with potential for even thicker substrates (up to 10 mm) for specialized applications.
Uniformity Control	Advanced MPCVD Process Engineering	Our in-house PhD team specializes in optimizing plasma parameters (e.g., platform height, gas flow, pressure) to ensure superior thickness and quality uniformity across large substrates.
Optical Finishing	Polishing capability: Ra < 5 nm (Inch-size PCD)	We provide the necessary double-sided optical polishing required to achieve the high transmission rates (up to 70%) demonstrated in the paper.
Custom Integration	Custom Metalization Services (Au, Pt, Ti, W, Cu)	If this research were extended to include thermal or electrical contacts, 6CCVD offers internal metalization capabilities to integrate diamond films directly into complex systems.

Engineering Support: 6CCVD’s in-house PhD team offers expert consultation on material selection and process optimization for similar High-Power Optical Window and Fusion Energy projects, ensuring optimal uniformity and quality for demanding environments.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

1,2 ，李成明 1 (1.北京科技大学新材料技术研究院，北京 100083；2.北京科技大学顺德研究生院，佛山 528399；3.北方工业大学机械与材料工程学院，北京 100144) 摘要: 大尺寸光学级金刚石膜的均匀生长一直是微波化学气相沉积(Microwave plasma chemical vapor deposition， MPCVD)金刚石研究领域的热点和难点之一，沉积台的结构与位置对于金刚石膜均匀性以及厚膜生长的长期稳定性至关重要。本研究通过 COMSOL 模拟结合实验研究了沉积台高度对衬底表面电场均匀性、等离子体状态和温度均匀性的影响规律，优化了光学级金刚石膜均匀生长的工艺参数，在最佳的沉积台(高度 2 mm)下沉积得到的 2 英寸金刚石膜(最大厚度 337 μm)，厚度不均匀性＜11%，从膜中心到边缘的拉曼半峰全宽为 3~4 cm -1 ，可见光波段内最高透过率为 69%~70%，10.6 μm 处红外透过率为 70%。结果表明：金刚石膜的厚度和品质较为均匀，实现了两

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Original Source

DOI: https://doi.org/10.15541/jim20230202