Nitrogen-Vacancy centers in diamond for current imaging at the redistributive layer level of Integrated Circuits
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2015-07-18 |
| Journal | Microelectronics Reliability |
| Authors | A. Nowodzinski, Mayeul Chipaux, LoĂŻc Toraille, V. Jacques, J.-F. Roch |
| Institutions | CEA Grenoble, Thales (France) |
| Citations | 80 |
| Analysis | Full AI Review Included |
Technical Documentation & Prospectus: NV Diamond for Wide-Field Magnetic Current Imaging
Section titled âTechnical Documentation & Prospectus: NV Diamond for Wide-Field Magnetic Current Imagingâ6CCVD specializes in delivering high-purity, custom-engineered MPCVD diamond solutions essential for advanced quantum sensing and semiconductor analysis. The research analyzed demonstrates the superior capability of ensemble Nitrogen-Vacancy (NV) centers in Single Crystal Diamond (SCD) for high-speed, vector-based Magnetic Current Imaging (MCI) on Integrated Circuits (ICs).
Executive Summary
Section titled âExecutive Summaryâ- Application Demonstrated: Wide-field Magnetic Current Imaging (MCI) performed on IC redistributive layers using an ensemble of Nitrogen-Vacancy (NV) centers in high-purity Single Crystal Diamond (SCD).
- Vector Measurement Advantage: NV centers enable the measurement of all three magnetic field components (Bx, By, Bz), resulting in an over-determined system of equations that significantly increases the robustness and noise tolerance of current reconstruction compared to traditional GMR or SQUID sensors.
- Speed and Operability: MCI acquisition time is extremely fast (approx. 10 seconds), achieving a factor of improvement over sensor scanning methods which require tens of minutes, and operates robustly at room temperature and atmospheric pressure.
- Performance Metrics: Achieved sub-micron (500 nm) spatial resolution and demonstrated a minimum detectable current of 0.5 mA in a non-optimized setup, paving the way for advanced IC failure analysis.
- Material Criticality: The study concludes that system performance hinges on optimizing the diamond crystal, specifically requiring materials with controlled NV center density and preferential orientation (e.g., <111> or <113> growth), a core capability of 6CCVD.
- Future Prospects: The vector measurement capability suggests new possibilities for characterizing complex, three-dimensional (3D) current flow within IC structures.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points define the performance achieved by the NV diamond wide-field magnetic imager setup:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Diamond Plate Dimensions (Used) | 4 x 4 x 0.25 | mm | Ultrapure diamond, 250 ”m thickness |
| Sensing Defect | Ensemble NV Centers | - | Located close to diamond surface |
| Spatial Resolution (Max) | 500 | nm | Limited by optical diffraction |
| Field of View (FOV) | 50 x 200 | ”m2 | Limited by laser spot size |
| Magnetic Components Measured | 3 (Bx, By, Bz) | - | Enables vector current reconstruction |
| Minimum Detectable Current (Imin) | 0.5 | mA | Achieved in non-optimized setup (3Ï) |
| Magnetic Field Acquisition Time | 10 | seconds | Significantly faster than scanning methods |
| Operating Conditions | Room Temperature | °C | Atmospheric pressure |
| Microwave Frequency Range | 2.87 ± 0.1 | GHz | Used for Electron Spin Resonance (ESR) |
| PL Pumping Wavelengths | 532 / 600-800 | nm | Required for optical polarization and readout |
Key Methodologies
Section titled âKey MethodologiesâThe core technique relies on wide-field NV magnetic imaging coupled with advanced current reconstruction algorithms:
- Material Preparation: An ultrapure Single Crystal Diamond (SCD) plate, typically 250 ”m thick, is grown via MPCVD with an ensemble layer of NV centers engineered close to one surface (active layer).
- Contact Placement: The diamond active layer is placed in direct contact with the Integrated Circuit (IC) sample to minimize the distance (zmes) between the current path and the sensor.
- Optical Pumping: A laser (532 nm or similar) is propagated through the diamond to optically polarize the NV centers into the ms = 0 spin state.
- MW Excitation: A microwave (MW) field in the 2.87 GHz range is applied externally via an antenna to induce transitions between the spin states (ms = 0 and ms = ±1).
- PL Readout: The magnetic field shifts the spin states (Zeeman splitting). These shifts are detected by monitoring the Photoluminescence (PL) signal, which is collected via a standard optical microscope and imaged onto a digital camera.
- Vector Field Calculation: By exploiting the four possible crystallographic orientations of the NV centers, the four corresponding resonance projections are measured, allowing the full three-component vector magnetic field B = (Bx, By, Bz) to be calculated for every pixel.
- Current Reconstruction: The vector magnetic field data is input into an over-determined system of equations (based on the inverted Biot-Savart Law and continuity constraint) in Fourier space. Inverse Fast Fourier Transform (FFT) is then applied to generate the 2D current density map (Jx, Jy).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD provides the specialized MPCVD diamond material required to replicate, improve, and extend this critical Magnetic Current Imaging research. The demonstrated need for optimized diamond crystals directly aligns with our core SCD engineering services.
Applicable Materials for Quantum Sensing
Section titled âApplicable Materials for Quantum SensingâThe key to increasing sensitivity and resolution in this technique lies in optimizing the NV density, homogeneity, and crystal orientation.
- Quantum Grade Single Crystal Diamond (SCD): Required for achieving high magnetic sensitivity and high spatial resolution (500 nm). We offer ultra-high purity materials with extremely low background nitrogen, essential for controlled NV formation.
- Preferentially Oriented SCD: References [7] and [8] specifically point to improving performance using (113)- or (111)-oriented substrates to achieve perfect preferential alignment of NV defects. 6CCVD offers custom crystal orientations necessary for maximizing vector sensitivity and simplifying data processing.
- Controlled NV Layer: We offer precision control over the depth and density of the implanted or grown NV ensemble layer (down to 0.1 ”m thick layers) to ensure the active sensing volume is as close as possible to the IC surface, maximizing signal strength.
Customization Potential for MCI Integration
Section titled âCustomization Potential for MCI Integrationâ6CCVDâs advanced engineering and fabrication capabilities ensure seamless integration into specialized imaging setups.
| Requirement from Paper | 6CCVD Solution & Capability | Impact on Research |
|---|---|---|
| Thickness Control | SCD thickness control from 0.1 ”m up to 500 ”m. Substrates up to 10 mm. | Enables ultra-thin sensors for closer IC proximity and reduced background signal. |
| Custom Dimensions | Plates/wafers up to 125 mm (PCD) and large area SCD plates; custom laser cutting. | Allows for precise matching of sensor size (e.g., 4 x 4 mm2 used) or cutting smaller pieces for specialized IC environments. |
| Surface Quality | SCD Polishing to Ra < 1 nm. | Critical for ensuring close contact with the IC surface (Zmes minimization) to maximize magnetic field coupling and resolution. |
| Microwave Integration | In-house metalization services (Au, Pt, Pd, Ti, W, Cu). | Allows researchers to deposit on-chip microwave antennae or bonding pads directly onto the diamond substrate for improved MW coupling efficiency. |
Engineering Support & Partnership
Section titled âEngineering Support & PartnershipâThe transition from a non-optimized setup (0.5 mA sensitivity) to a commercial solution requires deep expertise in diamond defect engineering.
- PhD-Level Consultation: 6CCVDâs in-house team of material scientists and physicists can assist researchers in selecting the optimal crystal growth parameters (e.g., doping gas mixtures, pressure, temperature) required for high-performance wide-field magnetic imaging projects.
- Global Supply Chain: We ensure reliable, documented, and globally shipped (DDU default, DDP available) high-purity diamond materials for time-sensitive quantum research.
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- 2012 - Space domain reflectometry for open failure localization
- 1989 - Using a magnetometer to image a two dimensional current distribution [Crossref]
- 2014 - Magnetometry with nitrogen-vacancy defects in diamond [Crossref]
- 2015 - Preferential orientation of NV defects in CVD diamond films grown on (113)-oriented substrates [Crossref]
- 2014 - Perfect preferential orientation of nitrogen-vacancy defects in a synthetic diamond sample [Crossref]
- 2008 - High-sensitivity diamond magnetometer with nanoscale resolution [Crossref]
- 2011 - Avoiding power broadening in optically detected magnetic resonance of single NV defects for enhanced DC magnetic field sensitivity [Crossref]