Skip to content
6CCVD Research

Synthesis and Properties of Electrically Conductive/Nitrogen Grain Boundaries Incorporated Ultrananocrystalline Diamond (N-UNCD) Thin Films Grown by Microwave Plasma Chemical Vapor Deposition (MPCVD)

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2021-09-11
JournalApplied Sciences
AuthorsMichelle Salgado-Meza, Guillermo MartĂ­nez-RodrĂ­guez, Pablo Tirado-CantĂș, Eliel Eduardo Montijo Valenzuela, Rafael GarcĂ­a
InstitutionsUniversidad de Hermosillo, Universidad de Guanajuato
Citations8
AnalysisFull AI Review Included

Technical Analysis and Documentation: Electrically Conductive N-UNCD Films

Section titled “Technical Analysis and Documentation: Electrically Conductive N-UNCD Films”

Executive Summary

Section titled “Executive Summary”

This research successfully optimized Microwave Plasma Chemical Vapor Deposition (MPCVD) parameters to maximize the electrical conductivity of Nitrogen-Incorporated Ultrananocrystalline Diamond (N-UNCD) thin films.

  • Core Achievement: Production of N-UNCD films exhibiting an electrical resistivity of approximately 1 Ohm·cm, representing a 5 to 6 order of magnitude improvement over undoped UNCD films.
  • Optimal Recipe: Maximum conductivity was achieved using a combination of high microwave power (4500 W) and high total plasma pressure (100 mbar).
  • Mechanism: Increased pressure and power correlate directly with higher substrate temperatures (up to ~880 °C), enhancing the incorporation of N atoms into the diamond grain boundaries.
  • Structural Integrity: XRD and Raman analysis confirmed the films consist purely of sp3 diamond nanograins (7-9 nm) with no detectable graphite impurity phase.
  • Grain Boundary Chemistry: Increased N incorporation reduces the presence of insulating transpoliacetilene (TPA) molecules in the grain boundaries, further boosting conductivity.
  • Key Application: These highly conductive, corrosion-resistant N-UNCD coatings are critical for developing next-generation Li-ion battery (LIB) electrodes, promising significantly longer cycle life and enhanced safety by preventing solid electrolyte interface (SEI) layer degradation.

Technical Specifications

Section titled “Technical Specifications”
ParameterValueUnitContext
Minimum Electrical Resistivity~1Ohm·cmAchieved at 4500 W and 100 mbar
Resistivity Improvement5 to 6Orders of MagnitudeCompared to undoped UNCD (≥106 Ohm·cm)
Optimal Microwave Power4500WSeries 3
Optimal Total Pressure100mbarCorrelated with maximum conductivity
Maximum Substrate Temperature~880°CAchieved at optimal growth conditions
MPCVD Frequency915MHzIPLAS System
Film Thickness Range (4500 W)200 to 550nmThickness decreases as pressure increases
Average Grain Size7 to 9nmCalculated via Scherrer-Debye equation
Preferred Orientation (XRD)(111)N/APreferential orientation for all N-UNCD films
Growth Time2hStandard duration for all experimental runs

Key Methodologies

Section titled “Key Methodologies”

The N-UNCD films were synthesized using the Microwave Plasma Chemical Vapor Deposition (MPCVD) technique, focusing on the systematic variation of power and pressure.

  1. Equipment: IPLAS MPCVD system operating at a microwave frequency of 915 MHz.
  2. Substrates: SiO2/Si and Si wafers.
  3. Chamber Preparation: Chamber evacuated to approximately 10-7 Torr prior to gas flow.
  4. Gas Mixture: A mixture of Argon (Ar), Methane (CH4), and Nitrogen (N2) was used.
    • Flow Rates: Ar (78 sccm) / CH4 (2 sccm) / N2 (20 sccm).
  5. Growth Parameters (Varied):
    • Microwave Power: Tested at 3000 W (Series 1), 4000 W (Series 2), and 4500 W (Series 3).
    • Total Pressure: Varied within each series (70, 80, 90, and 100 mbar).
  6. Temperature Control: Substrate surface temperature (ranging from 717-880 °C) was measured using a pyrometer.
  7. Characterization: Films were analyzed using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Raman Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Four-Point Probe measurements for electrical conductivity.

6CCVD Solutions & Capabilities

Section titled “6CCVD Solutions & Capabilities”

6CCVD is uniquely positioned to support and extend this research into high-performance, electrically conductive diamond films for energy storage and advanced electronics. Our expertise in MPCVD growth, customization, and material doping ensures optimal material delivery for demanding applications like Li-ion battery electrodes.

Research Requirement6CCVD Solution & Value Proposition
Ultrananocrystalline Diamond (UNCD)Polycrystalline Diamond (PCD) Capabilities: N-UNCD is a specialized form of PCD. 6CCVD offers high-quality MPCVD PCD films with precise control over grain size and boundary chemistry, essential for replicating and optimizing N-UNCD structures.
Thin Film Thickness ControlPrecision Thickness: The paper utilized films between 200 nm and 550 nm. 6CCVD routinely delivers PCD films with thickness control from 0.1 ”m up to 500 ”m, ensuring the exact dimensions required for efficient electrode coating are met.
High Electrical Conductivity (1 Ohm·cm)Boron-Doped Diamond (BDD) Alternative: For applications requiring ultra-low resistivity, 6CCVD offers heavily Boron-Doped Diamond (BDD), available in both Single Crystal (SCD) and Polycrystalline (PCD) formats, providing stable, metallic-like conductivity for electrochemical systems.
Large Area ScalingCustom Dimensions: While the paper used small substrates, 6CCVD can supply custom PCD plates/wafers up to 125 mm in diameter, enabling the scaling required for commercial LIB electrode manufacturing.
Electrode IntegrationIntegrated Metalization Services: The development of functional electrodes requires robust contacts. 6CCVD offers internal metalization capabilities, including deposition of Ti, Pt, Au, Pd, W, and Cu, allowing researchers to receive fully integrated, ready-to-use diamond electrodes.
Surface QualityAdvanced Polishing: For applications requiring minimal surface roughness (e.g., to ensure uniform coating or contact), 6CCVD provides polishing services achieving Ra < 5 nm on inch-size PCD wafers.
Process OptimizationExpert Engineering Support: The success of N-UNCD relies on precise control of gas ratios, pressure, and power. 6CCVD’s in-house PhD team can assist with material selection and MPCVD recipe optimization for similar corrosion-resistant electrode projects.

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

View Original Abstract

Research and development have been performed to investigate the effect of total pressure and microwave power on the electrical conductivity of nitrogen (N) atoms’ grain boundaries incorporated ultrananocrystalline diamond (N-UNCD) films grown by microwave plasma chemical vapor deposition (MPCVD). Insertion of N atoms into the UNCD film’s grain boundaries induces N atoms chemical reaction with C-atoms dangling bonds, resulting in release of electrons, which induce electrical conductivity. Four-point probe electrical measurements show that the highest electrically conductive N-UNCD films, produced until now, exhibit electrical resistivity of ~1 Ohm.cm, which is orders of magnitude lower than the ≄106 Ohm.cm for undoped ultrananocrystalline diamond (UNCD) films. X-ray diffraction analysis and Raman spectroscopy revealed that the growth of the N-UNCD films by MPCVD do not produce graphite phase but only crystalline nanodiamond grains. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of nitrogen (N) in the N-UNCD films and the high conductivity (no electrical charging is observed during XPS analysis) shown in electrical measurements.

Tech Support

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2010 - Status review of the science and technology of ultrananocrystalline diamond (UNCDℱ) films and application to multifunctional devices [Crossref]
  2. 2018 - Boron doping of ultrananocrystalline diamond films by thermal diffusion process [Crossref]
  3. 2001 - Synthesis and characterization of highly-conducting nitrogen-doped ultrananocrystalline diamond films [Crossref]
  4. 2003 - Bonding structure in nitrogen doped ultrananocrystalline diamond [Crossref]
  5. 2016 - Nitrogen incorporated ultrananocrystalline diamond microstructures from bias-enhanced microwave N2/CH4-plasma chemical vapor deposition [Crossref]
  6. 2015 - N-type conductive ultrananocrystalline diamond films grown by hot filament CVD [Crossref]
  7. 2004 - Mechanism of high n-type conduction in nitrogen-doped nanocrystalline diamond [Crossref]
  8. 2007 - Doped diamond: A compact review on a new, versatile electrode material [Crossref]

Reads Similar to This

Nonlinear Optical Properties of NV-doped Diamond Crystal Studied Using Z-Scan Method Temperature distribution in a laser-heated diamond anvil cell as described by finite element analysis Effects of Diamond Content on the Thermal Conductivity of Copper Matrix Composite Materials Prepared by Cold Spraying