Исследование структурных и морфологических свойств HPHT алмазных подложек
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2018-01-01 |
| Journal | Физика и техника полупроводников |
| Authors | П.А. Юнин, П. В. Волков, Ю Н Дроздов, А.В. Колядин, С. А. Королев |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: HPHT Diamond Substrate Characterization
Section titled “Technical Documentation & Analysis: HPHT Diamond Substrate Characterization”This documentation analyzes the structural and morphological defects identified in commercial HPHT diamond substrates, highlighting the critical need for advanced material characterization and superior material quality, capabilities offered directly by 6CCVD’s MPCVD manufacturing process.
Executive Summary
Section titled “Executive Summary”HPHT diamond substrates marketed for high-quality Chemical Vapor Deposition (CVD) homoepitaxy exhibit significant structural and morphological defects requiring specific characterization beyond typical jewelry grading.
- Problem Identification: Characterization based solely on “jewelry type” is insufficient for electronic-grade CVD diamond growth, leading to unpredictable epitaxial results.
- Morphological Defects: Substrates demonstrated critical geometric imperfections, including poor face non-parallelism (wedge up to 20 µm), significant central bow/warp (1-2 µm), and unacceptable medium-scale roughness (up to 9.5 nm).
- Polishing Artifacts: Large-scale surface deformation (low Rsur) was identified as primarily a consequence of the polishing process, not inherent bulk lattice strain (Rlat > 100 m).
- Structural Non-Uniformity: X-ray Diffraction (XRD) confirmed significant variations in both lattice parameter (a) and structural quality (Δω up to 64 arc seconds) across the face of single substrates, compromising epitaxial homogeneity.
- Critical Need: Routine, non-destructive diagnostic methods are necessary to control critical parameters (e.g., surface roughness Ra < 1 nm, wedge angle < 0.2°) before substrates are used for electronic applications.
- Solution: 6CCVD provides materials engineered specifically for epitaxy, ensuring ultra-low roughness and tight structural specifications necessary for high-performance device fabrication.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value Range | Unit | Context/Method |
|---|---|---|---|
| Substrate Dimensions | 3.5 × 3.5 to 4 × 4 | mm | Investigated Commercial HPHT Samples (001) |
| Thickness Variation (Wedge) | Up to 20 | µm | Low Coherence Optical Interferometry (Sub2) |
| Opposite Face Angle | Up to 0.3 | ° | Derived from max thickness wedge |
| Central Surface Bow/Warp | 1-2 | µm | OIMBS/Talysurf Analysis |
| Off-Cut Angle (Δ) | 0.1-1.5 | ° | Measured, lower for Monosectoral Substrates |
| Micro-Scale Roughness (σ ACM) | 0.2-1.0 | nm | AFM (1 x 1 µm frame) |
| Medium-Scale Roughness (σ OIMBS) | 1.7-9.5 | nm | Optical Interferometry (1 x 1 mm frame) |
| Optical Surface Curvature (R sur) | 2-13 | m | Low radius indicating high deformation |
| Lattice Curvature (R lat) | > 100 | m | High radius indicating minimal bulk strain |
| XRD Rocking Curve Width (Δω 004) | 30-64 | arc seconds (“) | Average width range across all substrates |
| Lattice Parameter (a) | 3.5665-3.5670 | Å | Variation due to impurity concentration/zones |
| Δω Standard Deviation (S(Δω)) | 1-13 | arc seconds (“) | Non-uniformity calculated over 9 points |
Key Methodologies
Section titled “Key Methodologies”The study utilized a multi-scale, complementary approach to characterize the substrates, combining optical, morphological, and structural analysis techniques.
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Low Coherence Optical Interferometry:
- Purpose: Mapping bulk thickness variation and wedge geometry.
- Method: Utilizes broadband light source coherence length to measure optical path difference, revealing non-parallelism (wedge) between faces.
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White Light Optical Interference Microscopy (OIMBS):
- Purpose: Measuring surface morphology and medium-scale roughness (Ra).
- Equipment: Talysurf CCI 2000 and Zygo New View 7300.
- Process: Characterized field of view up to 0.9 x 0.9 mm and whole substrate surfaces, identifying macro-defects like diagonal polishing scratches and central bow.
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Atomic Force Microscopy (AFM):
- Purpose: Measuring micro-scale roughness (σ ACM) down to the sub-nanometer level.
- Equipment: CMM-2000.
- Parameters: Frame size 1 x 1 µm. Essential for resolving small-scale surface features left by final polishing steps.
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High-Resolution X-Ray Diffractometry (XRD):
- Purpose: Mapping structural quality (Δω) and lattice parameter (a).
- Equipment: Bruker D8 Discover, high-resolution scheme.
- Setup: Used a Ge(220) four-reflection monochromator and a 0.3 mm collimator.
- Mapping: Measurements taken at 9 points (3 × 3 grid, 1.5 mm step) to determine spatial uniformity of (004) reflection rocking curve width (Δω) and Bragg angle.
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Off-Cut Angle Measurement:
- Purpose: Determine the deviation (Δ) of the surface relative to the crystallographic (001) plane. This angle strongly affects etching rates in plasma.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”The findings of this paper confirm that achieving electronic-grade performance requires precise control over morphology and structural integrity—exactly the strengths of 6CCVD’s engineered MPCVD diamond. We offer customized solutions that resolve the critical deficiencies identified in commercial HPHT materials.
Applicable Materials
Section titled “Applicable Materials”To replicate or extend this research with superior structural uniformity and surface quality, 6CCVD recommends:
- Optical Grade SCD (Single Crystal Diamond): Optimized for minimal impurities and structural uniformity, ensuring low Δω values (significantly better than the 30”-60” reported) essential for high-quality homoepitaxy.
- Electronic Grade SCD Substrates: Ideal for achieving the necessary high structural quality and purity required for advanced electronic device fabrication.
- Heavy Boron Doped PCD or BDD Substrates: For applications requiring conductivity or specialized electrochemical properties, manufactured with uniform doping profiles.
Technical Advantage & Customization Potential
Section titled “Technical Advantage & Customization Potential”The paper clearly states that polishing technology caused severe surface bowing and high medium-scale roughness (up to 9.5 nm). 6CCVD directly addresses this primary failure point:
| Defect Identified in Paper | 6CCVD Engineering Solution | Capability Specification |
|---|---|---|
| High Medium-Scale Roughness (1.7-9.5 nm) | Advanced proprietary chemo-mechanical polishing (CMP) | Ra < 1 nm (SCD) or Ra < 5 nm (Inch-size PCD) |
| Severe Bowing/Warping (Polishing Artifact) | Stress-free polishing techniques and strict metrology | Substrates guaranteed minimal residual stress and near-zero bow/wedge. |
| Small Lateral Dimensions (4 x 4 mm) | Large area manufacturing capability | PCD plates/wafers up to 125 mm |
| Structural Non-Uniformity (Variable Δω, ‘a’) | High-purity MPCVD growth control | Consistent crystallographic quality and precise orientation control, including targeted off-cut angles (Δ < 0.2°). |
Engineering Support
Section titled “Engineering Support”6CCVD’s in-house PhD engineering team understands the critical relationship between substrate quality and epitaxy success. We assist customers in material selection for similar High-Quality CVD Homoepitaxial Growth projects, ensuring material specifications meet the demands for tight control over structural (Δω) and morphological (Ra, wedge angle) parameters.
We offer:
- Custom Dimensions and Thickness: SCD layers from 0.1 µm up to 500 µm, grown on highly uniform substrates (up to 10 mm thick).
- Precision Orientation: Substrates delivered with measured and verified off-cut angles, crucial for step-flow growth and uniform etching, addressing the variable Δ identified in the research.
- Custom Metalization: Full internal capability to apply necessary thin films (Au, Pt, Pd, Ti, W, Cu) for device processing directly onto the SCD or PCD material.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
AbstractThe morphological and structural properties of a series of high-pressure high-temperature (HPHT) single-crystal diamond substrates are comprehensively studied by white-light optical interference microscopy, atomic-force microscopy, and X-ray diffraction analysis. Procedures that provide a means for characterizing the substrate parameters most critical for epitaxial application with the laboratory equipment are described. It is shown that the jewelry-type characterization of diamond substrates is insufficient to assess the possibility of their use for the epitaxial growth of chemical-vapor-deposited (CVD) diamond.