Growth Feature of Diamond-Like Carbon Films by Various Vacuum Plasma Methods
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2017-01-01 |
| Authors | Zhifeng Wang, Bing Hong Zhou, Zhu-Bo Liu, Zhiyong He |
| Institutions | Taiyuan University of Technology |
| Analysis | Full AI Review Included |
Technical Analysis & Documentation: Advanced Carbon Film Engineering
Section titled āTechnical Analysis & Documentation: Advanced Carbon Film Engineeringā6CCVD provides high-specification, synthesized MPCVD diamond materials essential for replicating and advancing research presented in āGrowth Feature of Diamond-Like Carbon Films by Various Vacuum Plasma Methods.ā While this study focuses on amorphous Diamond-Like Carbon (DLC), the findings regarding surface morphology control, spĀ²/spĀ³ hybridization, and optical band gap tuning are directly applicable to the development of next-generation crystalline diamond components (SCD, PCD, BDD).
Executive Summary
Section titled āExecutive SummaryāA comparison of four primary vacuum plasma deposition techniques (RF-MS, PLA, IBD, CVAE) for producing Diamond-Like Carbon (DLC) films highlights the critical link between deposition methodology and resulting material performance:
- Property Variation: Microstructure, surface roughness (RMS), and optical band gap (Eg) were successfully tuned by adjusting the deposition technique.
- Structural Extremes: CVAE produced films with the highest disordering of CspĀ² clusters and the smallest graphite grain size (9.2 Ć ), leading to the highest roughness (1.7 nm RMS).
- Optimal Smoothness & spĀ³ Content (PLA): Pulse Laser Ablation (PLA) yielded the smoothest surface morphology (0.5 nm RMS) and the highest optical band gap (1.42 eV), indicating a greater fraction of desirable spĀ³ (diamond-like) bonding.
- Optical Performance: RF-Magnetron Sputtering (RF-MS) demonstrated the best overall optical transmittance (50-60% in the 450-1000 nm range) among the four methods.
- Thickness Control: All tested films maintained uniform thickness within a tight range (150-180 nm), demonstrating precise control over thin-film growth regardless of the plasma method.
- Research Implication: This study confirms that precise control over ion energy and density is paramount for engineering carbon films with targeted mechanical and optical characteristics.
Technical Specifications
Section titled āTechnical SpecificationsāThe following parameters summarize the input variables and key structural/optical results derived from the comparative study:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Film Thickness (Target) | 150 - 180 | nm | Controlled by deposition time |
| Substrates Used | Si (100), Quartz Glass | N/A | Substrate base materials |
| Base Pressure (Pre-Deposition) | 6 Ć 10-4 | Pa | Achieved prior to deposition |
| Ion Etching Energy (Ar+) | 4 | KeV | Substrate cleaning step |
| Ion Etching Current Density | ~25 | A/m2 | Substrate cleaning step |
| Highest ID/IG Ratio (RF-MS) | 2.1 | N/A | Correlates to highest CspĀ² cluster size (19.5 Ć ) |
| Lowest ID/IG Ratio (CVAE) | 0.47 | N/A | Correlates to highest CspĀ² disordering |
| Smallest CspĀ² Cluster Size (CVAE) | 9.2 | Ć | Calculated grain size of graphite |
| Largest CspĀ² Cluster Size (RF-MS) | 19.5 | Ć | Calculated grain size of graphite |
| Lowest RMS Roughness (PLA) | 0.5 | nm | Achieved the smoothest surface morphology |
| Highest RMS Roughness (CVAE) | 1.7 | nm | Result of large graphitic particle formation (droplets) |
| Highest Optical Band Gap (PLA) | 1.42 | eV | Correlates to higher spĀ³ fraction |
| Lowest Optical Band Gap (RF-MS) | 0.93 | eV | Correlates to lower spĀ³ fraction |
| Optical Transmittance | 50 - 60 | % | Measured in the 450-1000 nm wavelength range |
Comparative Deposition Parameters (Table 1 Summary)
Section titled āComparative Deposition Parameters (Table 1 Summary)ā| Method | Graphite Target Diameter (mm) | Process Pressure (Pa) | Key Discharge Parameter |
|---|---|---|---|
| RF-MS | 50 | 0.2 (+Ar) | 1250 V |
| PLA | 20 | 2 Ć 10-3 | Nd: YAG, 355 nm, 10 Hz, 7 ns pulse |
| IBD | 80 | 5 Ć 10-2 (+Ar) | 5000 V |
| CVAE | 30 | 2 Ć 10-3 | 350 V, 3 Hz pulse frequency |
Key Methodologies
Section titled āKey MethodologiesāThe experiment compared the structural, morphological, and optical outcomes of DLC films synthesized via four distinct vacuum plasma techniques on Si (100) and quartz substrates.
- Substrate Preparation: Silicon and quartz substrates were cleaned via ultrasonic agitation for 20 minutes sequentially in acetone, ethanol, and deionized water.
- Vacuum & Etching: Substrates were placed in a high-vacuum chamber (base pressure 6 Ć 10-4 Pa). An Ar+ ion sputtering source (4 KeV, ~25 A/m2) was used for 15 minutes to remove surface oxide layers.
- Deposition: DLC films were deposited using graphite targets (99.5% purity) at a sample holder rotation speed of 2 rev/min. A bias voltage of ~300 V was applied during deposition.
- Thickness Control: Film thickness was maintained between 150 nm and 180 nm across all methods, measured using a step device (Ambios Technology XP-2).
- Microstructure Analysis (Raman): A Renishaw inVia Raman spectrometer (514.5 nm Ar-ion laser) was used to determine the ID/IG ratio, G-peak position, and CspĀ² cluster size, which characterize the spĀ²/spĀ³ bonding ratio and disorder.
- Surface Morphology (AFM): Atomic Force Microscopy (AFM) in tapping mode (Solver-PRO P47) was used to measure surface roughness (RMS) on a 1 Āµm x 1 Āµm scanning scope.
- Optical Characterization (UV-Vis): Transmittance was measured using a UV-1201 UV-Visible spectrophotometer across the 200 nm to 1100 nm range, allowing for the calculation of the optical band gap (Eg) via the Tauc relation.
6CCVD Solutions & Capabilities
Section titled ā6CCVD Solutions & CapabilitiesāThe research demonstrates the stringent requirements necessary for tuning carbon film properties, a challenge 6CCVD routinely addresses in the synthesis of high-performance MPCVD diamond. We offer the precision materials and customization services needed to meet the stringent specifications for high spĀ³ content, surface smoothness, and tailored optical properties demanded by advanced applications.
Applicable Materials
Section titled āApplicable MaterialsāTo replicate or extend the advanced optical and structural properties explored in this DLC research, 6CCVD recommends the following materials for true diamond components:
| Material Grade | Application Suitability | Key 6CCVD Capability Match |
|---|---|---|
| Optical Grade Single Crystal Diamond (SCD) | High spĀ³ Content / Ultra-Smooth Optics: Ideal replacement for DLC where maximum transparency, hardness, and thermal management are required. Achieves fundamental spĀ³ bonding purity beyond amorphous DLC limits. | Custom thickness (0.1Āµm - 500Āµm); Superior Polishing (Ra < 1nm) |
| Optical Grade Polycrystalline Diamond (PCD) | Large-Area Windows/Coatings: Suitable for scaling up transparent protective coatings where large deposition areas (up to 125mm wafers) are necessary. | Large area capability (up to 125mm diameter); Polishing capability (Ra < 5nm) |
| Boron-Doped Diamond (BDD) | Electrochemical & Electronic Tuning: Relevant for research extending the electrical characteristics of tunable carbon films, offering metallic or semiconducting diamond substrates based on precise doping levels. | Custom doping levels; Thickness up to 10mm (substrate) |
Customization Potential
Section titled āCustomization PotentialāThe experimental findings underscore the need for precise engineering control, especially concerning film thickness (150-180 nm) and substrate integration (Si, Quartz). 6CCVD offers unmatched flexibility in meeting these criteria:
- Thin Film Capability: 6CCVD specializes in ultra-thin SCD and PCD films, easily meeting the 150 nm requirement down to 0.1 Āµm precision.
- Dimensional Scaling: While the paper used small laboratory targets, 6CCVD provides deposition and fabrication services for SCD and PCD wafers up to 125 mm in diameter.
- Superior Surface Quality: The research cited 0.5 nm RMS as the smoothest DLC surface (PLA method). 6CCVD guarantees Ra < 1 nm for Single Crystal Diamond (SCD) and Ra < 5 nm for inch-size Polycrystalline Diamond (PCD), providing a superior starting point for advanced optical and protective coatings.
- Custom Substrate & Metalization: We support research requiring integration onto customer-supplied substrates (like Si or Quartz). Furthermore, 6CCVD offers in-house capability for advanced multi-layer metalization, including Au, Pt, Pd, Ti, W, and Cu contact layers, critical for high-frequency or high-power electronic applications that often utilize DLC films.
Engineering Support
Section titled āEngineering SupportāThis research highlights the complexity of tuning materials properties through plasma parameters. 6CCVDās in-house PhD-level engineering team specializes in the fundamental physics and chemistry of Microwave Plasma Chemical Vapor Deposition (MPCVD).
We provide dedicated support for projects in:
- Advanced Optical Devices: Selecting SCD or polished PCD for optimal transparency and thermal management, addressing surface smoothness requirements (e.g., for high-power laser windows).
- Protective Coatings: Choosing the correct diamond grade and polishing specification for wear-resistance applications, drawing on the observed structural differences in spĀ² bonding.
- Microelectronic Integration: Assisting with material selection (SCD/BDD) and metalization schemes for projects requiring diamond materials on Si or other unique substrates, ensuring optimal electrical and thermal performance.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We deliver globally (DDU default, DDP available).
View Original Abstract
Diamond-like carbon (DLC) films were prepared on silicon substrate using four different vacuum plasma methods: magnetron sputtering (MS), pulse laser ablation (PLA), ion beam deposition (IBD) and pulse cathode vacuum arc evaporation (CVAE).The microstructure, surface morphology and optical properties of the DLC films were investigated by Raman spectroscopy, atomic force microscope (AFM) and UV-visible spectrophotometer.The results showed that the films prepared by different vacuum plasma methods varied in the microstructure.The film prepared by CVAE possessed the smallest grain size of graphite with the highest disordering of Csp2 clusters, while more disordered Csp2 clusters presented in the DLC film due to the high ions energy density during PLA.Meanwhile, the deposition methods mainly affected the size of particles and roughness of the DLC films under the same thickness.The film by PLA shows a quite smooth surface structure with uniform particle size.In terms of the optical properties, the films prepared by magnetron sputtering expressed the best optical performance among the four vacuum plasma methods.