Effect of temperature on the (100) surface features of type Ib and type IIa large single crystal diamonds
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2015-01-01 |
| Journal | Acta Physica Sinica |
| Authors | He Zhang, Shangsheng Li, Taichao Su, Meihua Hu, Zhou You-Mo |
| Citations | 6 |
| Analysis | Full AI Review Included |
Technical Documentation and Analysis: Temperature Effects on (100) SCD Surface Features
Section titled âTechnical Documentation and Analysis: Temperature Effects on (100) SCD Surface FeaturesâDocumentation generated by 6CCVD Material Science Division based on: Zhang He et al. Effect of temperature on the (100) surface features of type Ib and type IIa large single crystal diamonds. Acta Physica Sinica, 64, 198103 (2015).
Executive Summary
Section titled âExecutive SummaryâThis paper investigates the relationship between synthesis temperature and surface morphology in High-Pressure High-Temperature (HPHT) synthesized Type Ib (Nitrogen-doped) and Type IIa (Ultra-pure) single-crystal diamonds (SCDs) grown on the (100) face using the Temperature Gradient Method (TGM).
- Morphology Control: Demonstrated the ability to control crystal habit, transitioning from Plate-like (low T) to Tower-like (medium T) and Spire Tower-like (high T) morphologies by tuning the growth temperature (1250 °C - 1340 °C).
- Purity Differentiation: Confirmed that Type IIa synthesis requires approximately 30 °C higher temperatures and the use of nitrogen scavengers (Ti/Cu) compared to Type Ib growth under similar conditions.
- Quality Benchmark: Raman spectroscopy confirmed the superior crystal quality of Type IIa SCD, evidenced by a significantly narrower Full Width at Half Maximum (FWHM) of 5.554 cm-1, compared to Type Ib SCD at 5.842 cm-1.
- Growth Mechanism: Laser Raman microscopy confirmed a step-flow growth mechanism on the (100) surface, exhibiting preferential carbon precipitation and nucleation at the crystalâs angularity regions over the central face.
- Rate Dependence: Growth rate was effectively controlled by adjusting the axial temperature gradient, achieving rates between 1.99 mg·h-1 and 4.33 mg·h-1 for crystals measuring 3-4 mm in diameter.
Technical Specifications
Section titled âTechnical SpecificationsâExtracted quantitative data points and performance metrics from the research paper.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Synthesis Pressure | 5.6 | GPa | Fixed HPHT condition |
| Temperature Range | 1250 - 1340 | °C | TGM Synthesis range |
| IIa T Offset vs Ib T | approx. 30 | °C higher | Required to achieve comparable morphology |
| SCD Crystal Size (Diameter) | 3 to 4 | mm | Resultant large single crystals |
| Maximum Growth Rate | 4.33 | mg·h-1 | Observed for Type Ib (1310 °C, high gradient) |
| Minimum Growth Rate | 1.99 | mg·h-1 | Observed for Type IIa (1310 °C, low gradient) |
| Temperature Gradient (Range) | 18.1 to 36.5 | °C·mm-1 | Controlled axial gradient for growth rate tuning |
| Type Ib Raman Peak Position | 1331.752 | cm-1 | Indicating minor stress/strain deviation |
| Type Ib FWHM | 5.842 | cm-1 | Quality metric (Higher Nitrogen Content) |
| Type IIa Raman Peak Position | 1331.833 | cm-1 | Closer to ideal 1332.7 cm-1 standard |
| Type IIa FWHM (Superior Quality) | 5.554 | cm-1 | Quality metric (Low Nitrogen Content, superior purity) |
| IIa Synthesis Additives | Ti/Cu | N/A | Used as nitrogen getters/scavengers |
Key Methodologies
Section titled âKey MethodologiesâThe synthesis employed the High-Pressure High-Temperature Temperature Gradient Method (HPHT-TGM) using a six-side cubic press.
- Carbon Source and Seeding: High-purity artificial graphite was used as the carbon source. High-grade, 0.5 mm single-crystal diamond seeds were utilized, with the (100) face selected as the primary growth surface.
- Catalyst System: A FeNiMnCo alloy was chosen as the metallic solvent/catalyst for Type Ib diamond growth.
- IIa Purity Management: For Type IIa diamond synthesis (requiring ultra-low nitrogen content), Ti/Cu additives were incorporated into the FeNiMnCo catalyst system to function as effective nitrogen scavengers.
- Pressure Application: Experiments were conducted under a stable, high-pressure condition of 5.6 GPa.
- Temperature Gradient Control (TGM): Temperature gradients ranging from 18.1 °C·mm-1 to 36.5 °C·mm-1 were applied across the chamber (using a combination of a graphite heater and insulation) to drive carbon transport from the hot (carbon source) end to the cooler (seed) end.
- Morphology Tuning: Growth temperature was precisely adjusted (1250 °C to 1340 °C) to achieve specific macroscopic morphologies: Plate-like (low T), Tower-like (medium T), and Spire Tower-like (high T).
- Characterization: Resultant crystals were analyzed using high-precision weighing (0.1 mg accuracy), optical microscopy, and Laser Raman Spectroscopy (Leica DM 2500 M) for surface step-flow analysis and crystal quality (FWHM measurement).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe research demonstrates the critical role of material purity and growth dynamics in achieving high-quality, large-format SCD. While the paper uses HPHT, 6CCVD specializes in MPCVD, offering far greater control, flexibility, and scalability for advanced diamond applications.
Applicable Materials for Replication and Extension
Section titled âApplicable Materials for Replication and Extensionâ| Application Area | Material Requirement (Paper) | 6CCVD Material Solution (MPCVD Advantage) |
|---|---|---|
| High Purity/Ultra-Low N | Type IIa SCD (FWHM 5.554 cm-1, requiring Ti/Cu getters) | Optical Grade SCD: 6CCVD achieves comparable or superior purity (sub-ppb nitrogen) routinely via MPCVD, eliminating the need for metallic scavengers and minimizing residual metal inclusion risks. |
| Doped Diamond | Type Ib SCD (Nitrogen-doped) | N-Doped or B-Doped SCD/PCD: 6CCVD offers precise, controllable gas-phase doping for research into color centers (e.g., NV centers) or customized electrical properties (BDD). |
| High-Power Electronics | High Thermal Conductivity (Implied by high purity) | Thermal Management Grade SCD: Our Type IIa material excels in thermal performance, available in thicknesses up to 500 ”m, ideal for high-power device heat spreaders. |
| Bulk Structures | Large single crystals (3-4 mm) | Custom Large SCD Plates: 6CCVD produces SCD plates up to 10 mm x 10 mm and large area Polycrystalline Diamond (PCD) wafers up to 125 mm, far surpassing the size limitations demonstrated by HPHT TGM. |
Customization Potential for Advanced Research
Section titled âCustomization Potential for Advanced Researchâ| Paper Requirement / Research Need | 6CCVD Customization Service | Technical Benefit |
|---|---|---|
| Specific Crystal Face Control | Precision-Oriented Substrates | SCD materials available with highly controlled crystal orientations (e.g., (100) or (111)) with orientation errors held to < 0.5°, essential for epitaxial research and device integration. |
| Surface Finish for Microscopy | Ultra-High Quality Polishing | Single Crystal Diamond (SCD) is polished to achieve surface roughness Ra < 1 nm, ensuring optimal results for high-resolution microscopy and Raman/optical characterization used in this study. |
| Device Integration | Custom Metalization Services | Internal capability for multi-layer metal stack deposition (e.g., Ti/Pt/Au, W, Cu, Pd). This supports the full transition from crystal growth studies to functional device prototypes. |
| Unique Dimensions | Laser Cutting and Shaping | Custom shaping, laser cutting, and precise dimensional control ensure the final product fits specialized experimental setups, regardless of complexity. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house team of PhD material scientists and technical engineers are experts in translating fundamental growth physicsâlike the relationship between temperature gradient, growth rate, and morphology demonstrated in this researchâinto scalable and repeatable MPCVD recipes. We provide consultation and support for projects requiring controlled doping, specific crystal morphology (e.g., optimizing axial vs. radial growth rates), and precise material selection for similar crystal growth dynamics and quality analysis projects.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We ship globally (DDU default, DDP available).
View Original Abstract
In this paper, by choosing FeNiMnCo alloy as a catalyst and the (100) face of a seed crystal as the growth face, high quality type Ib and type IIa large diamond single crystals (diameter about 3-4 mm) can be successfully synthesized using temperature gradient method, at 5.6 GPa pressure and different temperatures between 1250-1340 â. To control the diamond crystal morphology, the growth temperature should be adjusted. Then the morphology of the synthesized large diamonds is plate-like at low temperatures, tower-like at medium temperatures, and spire tower-like at high temperatures. For the same crystal morphology, the synthetic temperature of type IIa diamond single crystals is about 30 â higher than that of type Ib. The central and angularity regions of the top (100) surface, for the synthesized samples of type Ib and type IIa large diamond single crystals at different temperatures, are examined by laser Raman microscope respectively. It is found that the black lines of the type Ib and type IIa large diamond single crystals become dimmed and dense on the same top surface from center to the edge. It is indicated that the priority growth mechanism is in the angularity regions, compared with the central regions. Namely the solute of carbon is primarily precipitated in the angularity regions of the (100) surface. With increasing synthesis temperature, the black lines on the top surface (100) of type Ib diamond single crystals become gradually denser, and the characteristics of the lines are transformed from irregular distribution to typical dendritic distribution. The reason of the above results is that the rate of carbon deposition (the growth rate of diamond crystal), which is along the direction of the diamond crystal [100], will gradually rise as the synthesis temperature of the crystal is increased. The characteristics of the lines on the top surfaces (100) of type IIa large diamond single crystals, which are synthesized under different temperatures, are similar to that of type Ib. However, the lines on the top (100) surface of type IIa diamonds are not so obvious and denser than that of type Ib diamonds at different synthesis temperatures. Similar characteristics of lines on the top (100) surface of both types of diamond single crystals can be explained by the axis and radial growth rate variation at different temperatures. These different characteristics of the lines are due to the fact that the growth rate of type IIa diamonds is slower than that of type Ib diamonds, and the nitrogen concentrations in type IIa diamonds are lower than those of type Ib diamonds. Finally, the full width at half maximum (5.554 cm-1) of the tower-like type IIa diamond is narrower than that (5.842 cm-1) of tower-like type Ib diamond from the test of Raman spectra. It is shown that the quality of type IIa diamond single crystals is better than that of type Ib.