Experimental Insights into Impurity Incorporation in Chemical Vapor Deposition Doped Diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-08-27 |
| Journal | physica status solidi (a) |
| Authors | V. Mortet, Axel Leschiutta |
| Institutions | Université de Lille, Centre National de la Recherche Scientifique |
| Analysis | Full AI Review Included |
Technical Documentation: Impurity Incorporation in MPCVD Diamond
Section titled âTechnical Documentation: Impurity Incorporation in MPCVD DiamondâExecutive Summary
Section titled âExecutive SummaryâThis analysis reviews over 100 literature sources detailing the incorporation efficiency (η) of Boron (B), Phosphorus (P), and Nitrogen (N) in Chemical Vapor Deposition (CVD) diamond, providing critical insights for optimizing next-generation electronic and quantum devices.
- Doping Hierarchy: Boron exhibits the highest incorporation efficiency (η), followed by Phosphorus, with Nitrogen consistently showing the lowest η, challenging assumptions based solely on atomic radius.
- Extreme Doping Levels: Maximum reported concentrations in epitaxial layers are 8.5 x 1021 cm-3 (B), 6 x 1020 cm-3 (P), and 3.3 x 1020 cm-3 (N), confirming diamondâs potential as a heavily doped semiconductor.
- Orientation Dependence: Phosphorus incorporation is strongly influenced by crystal orientation, with (111) layers achieving significantly higher concentrations and η than (100) layers.
- Unconventional Surfaces: Boron incorporation efficiency can exceed unity (η > 1) on unconventional orientations like (113), suggesting new avenues for optimizing p-type conductivity.
- Precursor Chemistry: The choice of precursor is critical; for Nitrogen, Ammonia (NH3) yields an order of magnitude higher η than molecular Nitrogen (N2), essential for controlled NV center formation.
- Sales Driver: These findings underscore the necessity of precise MPCVD control over precursor ratios and substrate orientation, core capabilities offered by 6CCVD for high-performance SCD and BDD materials.
Technical Specifications
Section titled âTechnical SpecificationsâThe following table summarizes key quantitative data points extracted from the comparative analysis of doped diamond synthesis.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Highest Boron Concentration | 8.5 x 1021 | cm-3 | Achieved in epitaxial (111) layer |
| Highest Phosphorus Concentration | 6 x 1020 | cm-3 | Achieved in epitaxial (111) layer |
| Highest Nitrogen Concentration (Epitaxial) | 3.3 x 1020 | cm-3 | Achieved using NH3 precursor |
| Boron Incorporation Efficiency (η) | > 1 | Unitless | Observed on unconventional orientations (e.g., (113)) |
| Phosphorus Incorporation Efficiency (η) | ~10-3 to 10-1 | Unitless | Highly sensitive to orientation ((111) > (100)) |
| Nitrogen Incorporation Efficiency (η) | 40-400 times lower than P | Ratio | Optimal efficiency comparison |
| Diamond Atomic Carbon Density (Cs) | 1.764 x 1023 | cm-3 | Reference density for D/C ratio calculation |
| Boron Ionization Energy (EA) | 0.36 | eV | Acceptor level (p-type) |
| Phosphorus Ionization Energy (ED) | 0.6 | eV | Deep donor level (n-type) |
| Nitrogen Ionization Energy (ED) | 1.4 | eV | Very deep donor level (relevant for NV centers) |
Key Methodologies
Section titled âKey MethodologiesâThe research reviewed focuses primarily on in situ impurity incorporation during Chemical Vapor Deposition (CVD), predominantly using Microwave Plasma CVD (MPCVD/PECVD) techniques.
- Growth Technique: Plasma-Enhanced Chemical Vapor Deposition (PECVD) was the primary synthesis method across the reviewed literature.
- Dopant Precursors:
- Boron (B): Diborane (B2H6) and Trimethylborane (TMB, B(CH3)3) were the most common precursors, with TMB favored for lower toxicity.
- Phosphorus (P): Phosphine (PH3) was the benchmark precursor due to high incorporation efficiency, despite its toxicity. Alternatives included Trimethylphosphine (TMP) and Tert-butylphosphine (TBP).
- Nitrogen (N): Molecular Nitrogen (N2) was widely used for simplicity, while Ammonia (NH3) and Nitrous Oxide (N2O) were explored for enhanced incorporation efficiency and NV center formation.
- Substrate Orientation: Epitaxial layers were grown on various Single Crystal Diamond (SCD) orientations, including:
- Conventional: (100) and (111).
- Unconventional: (113), (115), (118).
- Doping Control Parameter: Dopant incorporation was primarily controlled by the atomic dopant-to-carbon ratio in the gas phase (D/C)g.
- Characterization: Dopant concentrations in the solid phase (D/C)s were predominantly measured using Secondary Ion Mass Spectrometry (SIMS).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials required to replicate and extend the high-precision doping strategies detailed in this research, particularly those targeting high-efficiency incorporation and quantum applications.
Applicable Materials
Section titled âApplicable Materialsâ| Application Requirement | 6CCVD Material Recommendation | Rationale |
|---|---|---|
| High-Conductivity p-type Layers (B concentrations up to 8.5 x 1021 cm-3) for ohmic contacts and power electronics. | Heavy Boron-Doped Diamond (BDD) SCD/PCD. | We provide precise control over B/C ratios to achieve metallic conductivity, essential for low-specific-resistance contacts. |
| High-Efficiency n-type Doping (P concentrations up to 6 x 1020 cm-3) for diodes and transistors. | Epitaxial Single Crystal Diamond (SCD) - (111) Orientation. | The research confirms (111) substrates yield the highest P incorporation. 6CCVD supplies high-quality, precisely oriented SCD substrates. |
| Quantum Applications (Controlled N doping for NV centers) and high-quality optical layers. | High-Purity Optical Grade SCD. | Our MPCVD process allows for ultra-low background nitrogen levels, enabling precise, controlled introduction of N (via N2 or NH3) for tailored NV density and delta-layer synthesis. |
Customization Potential
Section titled âCustomization PotentialâThe research highlights that optimal doping often relies on specific, non-standard parameters. 6CCVDâs custom capabilities directly address these needs:
- Custom Substrate Orientation: We offer epitaxial growth on standard (100) and (111) substrates, and specialize in custom orientations, including the high-efficiency (113), (115), and (118) surfaces, crucial for maximizing B and P incorporation efficiency (η > 1 reported for B on (113)).
- Custom Dimensions and Thickness: We supply SCD and PCD plates/wafers up to 125mm in diameter. Epitaxial layer thickness can be precisely controlled from 0.1”m to 500”m, supporting both thin-film device layers and thick substrates (up to 10mm).
- Precision Polishing: To ensure the favorable surface morphology required for high-efficiency epitaxial growth, 6CCVD guarantees ultra-smooth surfaces: Ra < 1nm for SCD and Ra < 5nm for inch-size PCD.
- Integrated Metalization: For device fabrication (diodes, MOSFETs), we offer internal metalization services, including deposition of Ti, Pt, Au, Pd, W, and Cu contacts, streamlining the path from material synthesis to functional device.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team provides expert consultation on material selection and growth recipe optimization for complex doping projects. We assist clients in navigating the trade-offs between precursor choice (e.g., PH3 vs. TMP for P-doping), crystalline orientation, and gas-phase ratios to achieve target solid-state concentrations for Power Electronics and Quantum Sensing applications.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Diamondâs exceptional properties as a wide bandgap semiconductor make it a leading candidate for nextâgeneration power electronics and quantum technologies. However, achieving precise control over the incorporation of active dopants, such as boron, phosphorus, and nitrogen, remains a key challenge in the fabrication of diamondâbased devices. Herein, over 100 literature sources are reviewed and analyzed to evaluate and compare dopant incorporation efficiency in singleâcrystal diamond synthesized via chemical vapor deposition. It also incorporates some data from polycrystalline layers for broader comparison. Specifically, the influence of dopant precursor concentration in the plasma and substrate orientation is investigated. The findings offer new insights and provide a useful reference metric for optimizing doped diamond synthesis.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
Section titled âReferencesâ- 2020 - Semiconductors And Semimetals