The peculiarities of CVD diamond coatings synthesis in abnormal glow discharge plasma using repetitively-pulsed mode
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-05-04 |
| Journal | Journal of Physics Conference Series |
| Authors | Stepan Linnik, A. Gaydaychuk, V. Okhotnikov |
| Institutions | National Research Tomsk State University, Tomsk Polytechnic University |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Repetitively-Pulsed CVD Diamond Synthesis
Section titled âTechnical Documentation & Analysis: Repetitively-Pulsed CVD Diamond SynthesisâExecutive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates an energy-efficient method for synthesizing high-quality polycrystalline diamond (PCD) coatings using a novel repetitively-pulsed AC abnormal glow discharge CVD system.
- Energy Efficiency: Achieved high deposition rates (7.0-7.4 ”m/h) comparable to constant power modes (7.5 ”m/h), while utilizing only half the input power (2.75 W vs. 5.5 W per plasma line).
- Material Quality: Produced high-purity PCD films characterized by well-faceted microcrystallites, confirmed by SEM, XRD, and Raman spectroscopy.
- Phase Purity: Raman analysis confirmed the primary diamond peak at 1332 cm-1 with minimal amorphous sp2 carbon content, indicating high material quality suitable for demanding applications.
- Scalability Potential: The study established the mutual influence of dual plasma lines, suggesting that combining multiple plasma sources can enhance uniformity for large-area diamond deposition (e.g., up to 125mm wafers).
- Process Reliability: The proposed system offers implementation simplicity and reliability, making the technology highly attractive for industrial diamond film deposition industries seeking high throughput and low energy consumption.
- Growth Parameters: Optimal growth occurred at 850 ± 25 °C, 60 ± 1 Torr, using a H2/CH4 ratio of 50:3 (approx. 6% methane).
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results, focusing on the optimal deposition parameters for high-quality PCD films.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Diamond Film Growth Rate (Pulsed) | 7.0 to 7.4 | ”m/h | Achieved across 50 Hz to 1000 Hz modulation |
| Diamond Film Growth Rate (Constant) | 7.5 ± 0.2 | ”m/h | Baseline comparison (40 kHz, 5.5 W power) |
| Reactor Pressure | 60 ± 1 | Torr | Optimal deposition conditions |
| Substrate Temperature | 850 ± 25 | °C | Maintained using IR pyrometer |
| Methane Concentration (H2/CH4 Ratio) | 50:3 | Ratio | Approximately 6% CH4 in H2 |
| Discharge Power (Pulsed Mode) | 2.75 | W | Per one plasma line (50% power reduction) |
| Discharge Power (Constant Mode) | 5.5 | W | Per one plasma line |
| Film Thickness Analyzed | 25 | ”m | Thickness of film shown in SEM analysis |
| Raman Diamond Peak | 1332 | cm-1 | Confirms high phase purity (sp3 bonding) |
| XRD Diamond Planes | {111}, {220}, {311} | Planes | Confirms polycrystalline diamond structure |
Key Methodologies
Section titled âKey MethodologiesâThe synthesis utilized a specialized AC abnormal glow discharge CVD system designed to operate in a repetitively-pulsed mode, focusing on energy efficiency and scalability.
- Reactor Configuration: Dual AC abnormal glow discharge system using two parallel plasma lines, allowing for channel switching frequencies between 50 Hz and 1 kHz.
- Gas Precursors: H2/CH4 gas mixture used as the working atmosphere. Methane content was optimized between 3% and 6% (volume flow), with experimental runs using a 50:3 ratio. Total flow rate varied from 50 to 300 ml/min.
- Plasma Generation: Power supply provided up to 20 A and 1000 V. Unipolar rectangular pulses were used for burning voltage, initiated by a short igniter voltage impulse (amplitude up to 1.2 kV).
- Substrate & Environment: Molybdenum rods and plates were used as substrates, placed on a cooled holder between the plasma lines and maintained at ground potential.
- Process Parameters: Deposition pressure was controlled between 20 and 100 Torr (optimized at 60 ± 1 Torr). Substrate temperature was actively maintained at 850 ± 25 °C.
- Characterization Techniques: Deposited films were analyzed for surface morphology (SEM - FEI Quanta 3D), phase composition (XRD - Shimadzu XRD-6000, Cu - Kα radiation), and bonding quality (Raman spectroscopy - NanoScan Technology Centaur I HR).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to support and advance research utilizing high-quality CVD diamond, particularly in energy-efficient plasma deposition techniques like the one described. Our capabilities ensure researchers can scale up their findings from laboratory experiments to industrial-grade components.
| Research Requirement / Challenge | 6CCVD Solution & Capability | Technical Advantage |
|---|---|---|
| Material Replication & Scaling | Optical Grade Polycrystalline Diamond (PCD) | We supply high-purity PCD wafers, matching the material quality (low sp2 content, strong {111} texture) required for high-performance applications derived from this research. |
| Large Area Deposition | Custom Dimensions up to 125mm | While the paper cited 35x200 mm substrates, 6CCVD offers PCD plates/wafers up to 125mm in diameter, facilitating the industrial scale-up of energy-efficient CVD reactors. |
| Film Thickness Control | PCD Thickness Range (0.1 ”m to 500 ”m) | We provide precise thickness control, from thin films (as used in the 25 ”m example) to robust, free-standing diamond substrates up to 500 ”m thick. |
| Advanced Substrate Integration | Custom Substrate Processing & Substrates up to 10mm | We can deposit diamond films onto customer-supplied materials (e.g., Molybdenum, Silicon, Tungsten) or provide thick diamond substrates (up to 10mm) for high-power applications. |
| Post-Processing & Finish | High-Precision Polishing Services | For applications requiring superior surface quality (e.g., optical windows or low-friction tools), we offer polishing services achieving roughness Ra < 5nm on inch-size PCD. |
| Electrode/Contact Integration | Custom Metalization Services | If the resulting diamond films require electrical contacts or heat sinks, 6CCVD offers in-house metalization using Au, Pt, Pd, Ti, W, and Cu layers. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in advanced MPCVD processes and material characterization. We can assist engineers and scientists with material selection, optimization of thermal management, and design consultation for similar high-efficiency plasma CVD projects.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We offer global shipping (DDU default, DDP available) to ensure timely delivery of your critical diamond materials.
View Original Abstract
We report about the features of polycrystalline diamond coatings CVD synthesis in repetitively-pulsed plasma of abnormal glow discharge. The discharge burning time was varied from 0.5 to 10 ms with proportional pauses. The dependences of deposited diamond films growth rate on the durations of the discharge burning and pauses are presented. The mutual influence of two plasma filaments on each other and onto the substrate has unequivocally established. Raman spectroscopy, X-ray diffractometry and SEM were used for identification of phase composition and microstructure of deposited films. Implementation simplicity and reliability of the proposed discharge system may find application in diamond film deposition industries.