Polycrystalline Boron-doped Diamond Electrolyte-solution-gate Field-effect Transistor Applied to the Measurement of Water Percentage in Ethanol
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-10-01 |
| Journal | Analytical Sciences |
| Authors | Yukihiro Shintani, Hiroshi Kawarada |
| Institutions | Waseda University |
| Citations | 7 |
| Analysis | Full AI Review Included |
Technical Documentation and Analysis: Polycrystalline BDD-SGFET for Nonaqueous Sensing
Section titled âTechnical Documentation and Analysis: Polycrystalline BDD-SGFET for Nonaqueous SensingâExecutive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates the superior performance of a Polycrystalline Boron-Doped Diamond Electrolyte-Solution-Gate Field-Effect Transistor (BDD-SGFET) for rapid water content analysis in ethanol, a critical application for biofuel and pharmaceutical quality control.
- Material Advantage: The use of a no-gate-insulator BDD channel provides exceptional chemical stability and sensitivity in nonaqueous solutions (ethanol).
- Speed Breakthrough: The BDD-SGFET achieved output stability in less than 9 seconds, demonstrating a four-times-faster response than conventional Si-ISFETs and a ten-times-faster response than standard glass electrodes.
- High Linearity: The sensor exhibited excellent linearity (R2 = 0.98) across the measured water percentage range, confirming its accuracy for in-line monitoring applications.
- Fabrication Requirements: The device relies on high-quality, MPCVD-grown polycrystalline BDD films with specific Ti/Au metalization contacts and precise channel geometry (W=0.4 mm, L=9 mm).
- 6CCVD Relevance: 6CCVD specializes in the custom fabrication of high-quality, heavily boron-doped polycrystalline diamond wafers, offering the precise material specifications and metalization services required to replicate and scale this advanced sensor technology.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Substrate Dimensions | 10 x 10 x 0.5 | mm | CVD-synthesized Polycrystalline Diamond |
| Channel Material | Polycrystalline BDD | N/A | Partially oxygen-terminated surface |
| Channel Width (W) | 0.4 | mm | Device geometry |
| Channel Length (L) | 9 | mm | Device geometry |
| Drain Voltage (Vds) | 0.5 | V | Operating condition for BDD-SGFET |
| Drain Current (Ids) | 5 | ”A/mm | Operating condition for BDD-SGFET |
| Sheet Carrier Density (Pre-treatment) | 3.8 x 1013 | /cm2 | BDD film specification |
| Carrier Mobility (Pre-treatment) | 8.5 | cm2/Vs | BDD film specification |
| Sheet Resistance (Pre-treatment) | 22 | kΩ/square | BDD film specification |
| Response Time (BDD-SGFET) | < 9 | s | Time to achieve stable output in 10% ethanol |
| Response Time (Si-ISFET) | > 40 | s | Comparison device performance |
| Response Time (Glass Electrode) | > 10 | min | Comparison device performance |
| Linearity (R2) | 0.98 | N/A | Correlation coefficient for water content measurement |
| Contact Metalization (Ti) | 20 | nm | Adhesion layer thickness |
| Contact Metalization (Au) | 100 | nm | Conductor layer thickness |
Key Methodologies
Section titled âKey MethodologiesâThe BDD-SGFET fabrication relies on precise MPCVD growth and post-processing techniques to achieve the required electrical and surface properties:
- Substrate Acquisition: Commercial CVD-synthesized polycrystalline diamond substrates (10 x 10 mm, 0.5 mm thick) were used.
- BDD Layer Deposition: Boron-doped diamond layers were deposited onto the substrates using a quartz-type Microwave Plasma CVD (MPCVD) reactor.
- Contact Metalization: Source and drain electrodes were formed by depositing a bilayer stack of Ti (20 nm) / Au (100 nm) using lift-off photolithography.
- Channel Definition: The contacts were positioned to define a channel width (W) of 0.4 mm and a length (L) of 9 mm.
- Passivation: Source/drain electrodes were encapsulated with nonconductive epoxy resin to ensure only the BDD channel surface was exposed to the solution.
- Surface Termination: Sensitivity was enhanced by modifying the direct-wetted diamond surface to a partially oxygen-terminated BDD surface via ultraviolet irradiation in an oxygen atmosphere.
- Measurement: The device was characterized using a source follower circuit and an Ag/AgCl reference electrode, maintaining a constant drain current (Ids) by applying a compensating gate-source voltage (Vgs).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the high-specification diamond materials and custom fabrication services necessary to replicate, optimize, and scale the BDD-SGFET technology described in this research.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate the high-speed, stable sensing demonstrated in this paper, researchers require heavily boron-doped polycrystalline diamond (PCD) films with controlled doping uniformity.
| 6CCVD Material Recommendation | Specification Match | 6CCVD Capability |
|---|---|---|
| Heavy Boron-Doped PCD | Polycrystalline structure, high carrier density (3.8 x 1013 /cm2), low sheet resistance (22 kΩ/square). | We offer custom BDD doping levels and thicknesses (0.1 ”m to 500 ”m) optimized for electrochemical and FET applications. |
| Polycrystalline Substrates | Required 0.5 mm thickness. | We supply robust PCD substrates up to 10 mm thick, suitable for large-scale device manufacturing. |
| Surface Finish | Requires precise surface control (e.g., oxygen termination). | We offer polishing services for PCD wafers up to inch-size with roughness Ra < 5 nm, ensuring optimal surface preparation for post-processing (UV/Ozone treatment). |
Customization Potential
Section titled âCustomization PotentialâThe success of the BDD-SGFET relies on precise geometry and contact integrity. 6CCVD offers comprehensive customization services that directly address the fabrication needs of this device:
- Custom Dimensions & Scaling: While the paper used 10 x 10 mm substrates, 6CCVD can supply PCD plates/wafers up to 125 mm in diameter, enabling high-throughput manufacturing of multiple sensors per wafer.
- Metalization Services: The device requires a specific Ti (20 nm) / Au (100 nm) contact stack. 6CCVD provides in-house, high-precision metalization services, including:
- Materials: Au, Pt, Pd, Ti, W, Cu.
- Patterning: Custom photolithography and lift-off processes to define the precise 0.4 mm x 9 mm channel geometry.
- Thickness Control: We offer precise control over the BDD layer thickness, ranging from 0.1 ”m to 500 ”m, allowing researchers to optimize the active layer for specific transconductance (gm) requirements.
Engineering Support
Section titled âEngineering SupportâThe development of advanced diamond sensors, particularly those relying on specific surface termination (e.g., partially oxygen-terminated BDD), benefits from expert consultation.
- Application Expertise: 6CCVDâs in-house PhD team specializes in the material science of diamond semiconductors and can assist researchers in selecting the optimal BDD grade and surface preparation protocols for similar nonaqueous sensing or biofuel quality control projects.
- Global Logistics: We ensure reliable, global shipping (DDU default, DDP available) of sensitive diamond components, supporting international research and development efforts.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
Section titled âReferencesâ- 2011 - J. Appl. Phys.