High Temperature Performances Of Cvd Single Crystal Diamond Detectors
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2016-10-26 |
| Authors | R. Pilotti |
| Institutions | University of Rome Tor Vergata |
| Citations | 7 |
| Analysis | Full AI Review Included |
High Temperature Diamond Detectors for Fusion Diagnostics: 6CCVD Material Solutions
Section titled âHigh Temperature Diamond Detectors for Fusion Diagnostics: 6CCVD Material SolutionsâAnalyzed Research Paper: âHigh Temperature Performances of CVD Single Crystal Diamond Detectorsâ (Pilotti et al., POS(ECPD2015)180)
This documentation connects the critical material and fabrication requirements identified in the studyâspecifically the need for ultra-high purity, custom-metalized Single Crystal Diamond (SCD) detectors operating in extreme temperature and radiation environmentsâwith the specialized manufacturing capabilities of 6CCVD.
Executive Summary
Section titled âExecutive Summaryâ- CVD Single Crystal Diamond (SCD) is confirmed as a superior material for high-temperature, harsh environment diagnostics, specifically in ITER Test Blanket Modules (TBMs) and Tokamaks.
- The research successfully demonstrated an innovative detector layout based on mechanical contact, eliminating performance-limiting elements like conductive glues and welding which fail above 170 °C.
- The novel mechanical SCD detector layout achieved stable operational performance up to 240 °C during J-V and C-V characterization tests.
- Commercial diamond detectors utilizing standard fabrication techniques showed unacceptable Signal/Noise ratio degradation above 180 °C, confirming the necessity of improved material assembly.
- Prototypes equipped with specialized high-temperature cables (MI) and metal-oxide connectors (MOC) showed promising performance under 14 MeV neutron irradiation up to 230 °C.
- Successful implementation relies critically on high-quality, custom-thickness SCD plates with precision-deposited Platinum (Pt) contacts, core competencies of 6CCVD.
- Future optimization focuses on materials capable of stable operation up to the required 300 °C and utilizing high-temperature metal contacts (e.g., Ag for 800 °C stability).
Technical Specifications
Section titled âTechnical SpecificationsâThe following key data points were extracted from the characterization and operational parameters of the CVD SCD detectors:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Detector Material Type | Single Crystal Diamond (SCD) | N/A | High Purity CVD Growth |
| SCD Thickness (Tested) | 500 | ”m | Used for mechanical layout prototype |
| SCD Lateral Dimension | 4.5 x 4.5 | mm | Dimensions of the SCD plate |
| Required TBM Neutron Flux | Up to 4 x 1014 | n cm-2s-1 | Defines radiation hardness requirement |
| Target Operational Temperature (ITER TBM) | Up to 400 | °C | Design specification limit |
| Stable Operating Limit (Mechanical Layout) | 240 | °C | Max T achieved during J-V/C-V stability tests |
| Stable Operating Limit (Commercial Detector) | 180 | °C | Max T for acceptable S/N ratio (> 5.5) in current mode |
| Metal Contact Material | Platinum (Pt) | N/A | Deposited via sputtering |
| Pt Contact Thickness | 100 | nm | Thickness deposited on both faces |
| Diamond Band Gap | 5.5 | eV | Intrinsic wide band gap property |
| Diamond Resistivity | > 1015 | Ωcm | Intrinsic material property |
Key Methodologies
Section titled âKey MethodologiesâThe innovative detector architecture and testing procedures focused on achieving mechanical stability and high-temperature performance:
- SCD Preparation: Single Crystal Diamond plates (4.5 x 4.5 mm side, 500 ”m thick) were utilized for the detector substrate.
- Thermal Annealing: The SCD films were annealed at 500 °C in vacuum for 1 hour to stabilize the material properties.
- Metalization: Two Platinum (Pt) electrical contacts (3mm diameter, 100 nm thick) were deposited onto both faces of the SCD film using a sputtering technique.
- Mechanical Assembly (Innovative Layout): The SCD detector was sandwiched between upper and lower metal electrodes, maintaining electrical contact via mechanical force and a small metallic spring, thus avoiding failure-prone glues and welding.
- Electrical Characterization: Current Density vs. Voltage (J-V) and Capacitance vs. Voltage (C-V) characteristics were measured across various temperatures up to 240 °C.
- Irradiation Testing (Current Mode): Commercial detectors were tested using a Sr-90 beta source up to 190 °C. Prototypes were tested under 14 MeV neutron irradiation (FNG) up to 230 °C.
- High-Temperature Connectivity: Prototypes utilized specialized mineral cables (MI, rated up to 800 °C) and metal-oxide connectors (MOC, rated up to 400 °C) to isolate electronics failure from material performance limits.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the advanced CVD diamond materials required to replicate and further optimize this high-temperature diagnostic technology, specifically targeting the 300 °C+ operating requirements of ITER TBMs.
Applicable Materials
Section titled âApplicable Materialsâ| Research Requirement | 6CCVD Applicable Material | Technical Justification & Specification |
|---|---|---|
| SCD for Pulse/Current Mode | Optical Grade Single Crystal Diamond (SCD) | Ultra-high purity material minimizes charge traps and dark current (thermal excitation), critical for maintaining a high S/N ratio above 200 °C. |
| High Temperature Stability | Heavy Boron Doped Diamond (BDD) (Extension) | While the paper focused on intrinsic SCD, BDD could be supplied for specialized electrochemical or thermal applications needing reliable conductivity up to 400 °C. |
| Harsh Environment/Dose Limit | Polycrystalline Diamond (PCD) Plates (Extension) | Available up to 125mm in diameter and up to 10mm thick, suitable for large-area coverage or as robust substrates for modular detector arrays in high-flux environments. |
Customization Potential
Section titled âCustomization PotentialâThe success of the mechanical layout relies on highly precise material dimensions and specific contact materials. 6CCVD provides end-to-end customization:
- Custom Dimensions and Thickness: The paper utilized 4.5 x 4.5 mm plates at 500 ”m thickness. 6CCVD specializes in custom sizing, supplying SCD material from 0.1 ”m up to 500 ”m thick and custom substrates up to 10 mm. We can supply materials precisely cut (e.g., laser cutting) to match specific mechanical mount geometries.
- Precision Metalization Services: Replication or optimization of the electrical contacts is critical. We offer certified in-house metalization services, including the Platinum (Pt) used in this study, as well as Au, Ti, W, and Pd, allowing researchers to test alternative high-temperature stable metals (like Ag, mentioned in the paper, or specialized barrier layers).
- Surface Preparation: Achieving intimate contact in a mechanical layout requires extreme flatness. We guarantee superior surface finishing, providing SCD polishing to Ra < 1 nm and high-area PCD polishing to Ra < 5 nm, ensuring reliable and uniform Schottky barrier formation.
Engineering Support
Section titled âEngineering Supportâ6CCVD acts as a technical partner, not just a supplier.
- Our in-house PhD team is specialized in optimizing diamond material properties for high-energy physics and harsh environment sensing, including advanced diagnostics for fusion reactors.
- We can assist with material selection to extend operational temperatures well beyond the 240 °C achieved in this study, advising on dopants, thickness control, and optimal metal contact stack composition for similar Tokamak Diagnostic projects.
- We facilitate global logistics, offering Global Shipping (DDU default, DDP available) to ensure rapid and secure delivery of custom-fabricated components directly to research facilities worldwide.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
In fusion applications (e.g.tokamaks) detectors must withstand a very harsh environment characterized by high temperatures and intense radiation fluxes.Conventional solid state detectors (e.g.silicon) cannot be operated at high temperatures and present serious dose limit.Among the possible alternatives to silicon, diamond based detectors are very promising because of their outstanding properties such as radiation hardness, high thermal conductivity and wide band gap.Diamond detectors were proposed as neutron detectors for the Radial Neutron Camera (RNC) and for the Tritium Breeding Module (TBM) of ITER.In the latter the detector working temperature can be up to 400 °C.A few studies, so far have been performed to study the behaviour of diamond detectors at high temperatures.In the present paper the performances of single crystal diamond detectors operated at high temperatures are reported.An innovative detector layout was studied which is based on a mechanical contact avoiding the use of critical components such as glue, welding, etc.A 500 ”m thick single crystal diamond plate with platinum electrical contacts was tested reaching temperatures up to 240 °C, its I-V and C-V characteristics were measured at increasing temperatures.The results demonstrated that the proposed innovative layout presents very interesting behaviour and stable response at high temperatures.Furthermore, a commercial detector was tested at temperatures up to 180 °C while operated in current mode using a beta source.The signal to noise ratio vs. temperature resulted acceptable up to about 170 °C.