Sandia serves the nation in developing and delivering leading- edge integrated photonics solutions for our customers and partners in the national security sector.
Our activities range from ground-breaking research through product delivery and qualification with a focus on high performance pathfinder solutions. We leverage the broad capabilities within Sandia’s MESA facility, including our co-located silicon and compound semiconductor fabs, deep R&D expertise, and low-volume manufacturing infrastructure to solve truly difficult problems.
Sandia partners with government agencies, private companies, and universities to collaborate on new technologies, provide expertise, deliver low volume solutions, and transfer technology.
Sandia’s unique capabilities include:
- A staff of > 60 photonics experts skilled in device design, modeling, simulation, epitaxy, device fabrication, integration, assembly, and test
- A silicon photonics line with a PDK supporting multi-project wafer runs
- A compound semiconductor fab with:
- custom MBE and MOCVD epitaxy capability in arsenides, phosphides, antimonides, and nitrides
- a photonic integrated circuit platform
- Custom lasers, VCSELs, modulators, waveguides, amplifiers, detectors, photovoltaics, transceivers, focal plane arrays
- A large toolset for heterogeneous integration, microsystem assembly, and packaging
- Testing and reliability qualification, especially in harsh environments
- Classified and trusted environments available
Areas of Expertise
The multi-mission environment of the Labs promotes a diverse, multi-disciplinary team of subject matter experts in fabrication labs and clean room facilities. Two important Sandia support labs - the Silicon Photonic Foundry and the III-V Photonic Integrated Circuit (PIC) Lab - are co-located inside the MESA facility.
Microsystems and Engineering Sciences Applications (MESA)
The multi-mission environment of the Labs promotes a diverse, multi-disciplinary team of subject matter experts in fabrication labs and clean room facilities. Two important Sandia support labs - the Silicon Photonic Foundry and the III-V Photonic Integrated Circuit (PIC) Lab - are co-located inside the MESA facility under the same 65,000 square foot roof.
Sandia National Laboratories, located on Kirtland Air Force Base in Albuquerque, NM, executes a multi-mission national security role that supports a diverse multi-disciplinary team of subject matter experts in fabrication labs and clean room facilities. The Sandia Microsystems and Engineering Sciences Applications (MESA) facility is the only semiconductor fabricator within the United States that has a silicon (Si) complementary metal–oxide–semiconductor (CMOS), Si photonics and production III-V processing capability co-located in the same facility. This capability seamlessly mixes strategically rad-hard CMOS and III-V compound semiconductor product deliveries with leading edge R&D in microelectronics, photonics, MEMS, and quantum within a high-rigor and high-flexibility fabrication process flow. A fully Trusted accreditation status, as well as limited access control processing, are also valuable MESA facility attributes.
Sandia’s national security mission responsibilities for the National Nuclear Security Administration (NNSA) and other Department of Defense (DoD) agencies have developed deep expertise in photonics, photovoltaics, focal plane arrays, advanced sensors, optical MEMS, plasmonics/metamaterials, advanced packaging, and reliability/security (especially for extreme or high-consequence environments). Work in these areas spans theoretical analysis, device fabrication and test, and advanced pathfinder products.
As a government-owned resource for the National Security Photonics Center (NSPC), Sandia can support commercial foundry activities by providing additional capacity for design, fabrication, and systems integration from technology readiness level (TRL) 1 to TRL6, and with certification as a trusted foundry MESA can produce electronics intended for high-consequence military applications. For example, IMI customers might utilize the Silicon Photonics Foundry multi project wafer (MPW) system and III-V PIC foundry to access materials or devices outside the immediate scope of the IMI foundry to fabricate novel prototypes for evaluation in defense applications.
Several of Sandia’s current photonics projects utilize heterogeneous integration of III-Vs and Si photonics with CMOS to realize novel advanced pathfinder products for satellite sensing, exascale computing, next generation alternative energy, and specific radiation hardened and classified applications. Extensive testing and evaluation labs available at Sandia may also enable rapid impact of the IMI on new products by supporting university and industry partners in the development of the complete design, simulation, and test infrastructure needed for rapid, low-cost manufacturing. Sandia National Laboratories also routinely supports defense contractor partners in technology maturation and transfer activities, and university partners via R&D collaborations and student fellowships/internships within the Laboratories.
The MESA facility comprises 400,000 sq ft of clean rooms and laboratories with providing a flexible fab with production rigor, adjacent Si and III-V cleanrooms, and all the standard fab & test tools. Over 150 equipment sets are maintained, supported and operated 24 hours per day, 5 days a week (3 shifts) in a secure environment with highly cleared staff. Tooling examples include: High NA 248nm Deep UV Lithography with resolution down to 110nm, E-beam lithography with 5nm resolution, NanoSEM CD metrology systems with LER capability for waveguide optimization, HDP oxide for cladding and low loss SiN for 2nd layer waveguides, Ion Implant, CMP and Deep Si Etch, 6 MOCVD and 4 MBE reactors for III-V growth, 3 FC-150 die level bonders, Silver and Gold electroplating, lift-off, wafer to wafer bonding and thinning.
III-V & Si Electronics
AlxGa1-xAs/GaAs, InxGa1-xAsyP1-y/InP, InxGa1-xAs /GaAs, AlGaN/GaN, InGaN, Si, SOI, AlN, Graphene. Full ASIC design using Cadence and Simulation via TCAD Silvaco, Sensor read out electronics (ROICs), Rad-Hard ASICs, structured ASICs, Secure Microprocessors, Low noise analog electronics design, III-V Amplifiers, Rad Hard Heterojunction Bipolar Transistors (HBT), High electron mobility transistors, Schottky Barrier Diodes, etc.
III-V & Si Photonics
Waveguides/devices in silicon, oxide, oxy-nitride, nitride, a-Si, a-Ge, InP, AlGaAs, InGaAs, GaN, Graphene. L-edit design and Lumerical, Silvaco simulation. VCSELs, DBR lasers, EAMs, High-gain & High-Psat SOAs, LEDs, Photonic Integrated Circuits (PICs) incorporating lasers, detectors, modulators, filters, Photovoltaics spanning UV to IR, Si photonic fj/bit modulators, integrated germanium detectors, low loss ridge and rib waveguides, 2 x 2 broadband and wavelength selective switches, silicon nitride edge couplers and cross overs, Mach-Zehnder modulators and surface grating couplers, wafer-level test and characterization.
III-V & Si MEMS
Si, polySilicon, a-Si, a-Ge, AlN, GaAs, GaN, LiNbO3, 32kHz -10 GHz AlN resonators, Inertial sensors, Actuators, BioMEMS, Microfluidics.
LiNbO3, AlN, GaAs, InP, Si SOI CMOS. Focal plane arrays bonded to Si CMOS ROICs, X-ray camera arrays, very large area stitched arrays, Si & III-V Photonics bonded to CMOS.
Failure Analysis & Reliability
Laser Based Techniques: TIVA, LIVA, E-Beam Based Techniques: PVC, CIVA, Atomic Force Microscopy, Laser Scanning Microscopy, SEM/TEM including nano-probing and environmental mode, FIB – Dual Beam and Backside circuit edit, TEM, SQUID, Deprocessing laboratory.
The InGaAsP/InP PIC program at Sandia National Labs resides within the MESA facility and is presently used for customer-specific photonic R&D, such as optical data sampling and RF-analog signal processing in the optical domain. Demonstrated capability exists to 40 Gb/s.
Compound III-V Photonics
State-of-Art Compound Semiconductor Photonics
Photonic Integrated Circuits and Lasers
Sandia National Laboratories has state-of-art photonic integrated circuit (PIC) design and fabrication capabilities and more than a decade of experience in the InP-based PIC technology. Sandia has proven and documented capabilities to monolithically integrate single-wavelength tunable diode lasers, modulators, amplifiers and interconnection optical waveguides on InP substrates for operation at telecom wavelengths. This capability rests on a foundation of state-of-the-art III-V semiconductor crystal growth and regrowth using metal-organic chemical vapor deposition (MOCVD) and post-growth quantum-well band-gap modification using quantum-well intermixing (QWI) methods to achieve the multiple band-edges and optical confinement needed for highly-functional PICs. PIC design and simulation is supported by experienced PhD-level staff spanning the complete design spectrum from optical guided-mode solvers and device electronics to complete optical circuits using eigenmode expansion, finite-difference time-domain, beam propagation methods.
The images above illustrate the sophisticated monolithic integration of passive waveguide photonics elements (such as waveguides, modulators, and switches) as well as active photonics elements including lasers, optical amplifiers, and photodetectors onto a single PIC. The capability enables compact high-performance PIC functions of integrated transmitter lasers and modulators, coherent optical receivers, and advanced telecom optical modulation formats such as DQPSK in single-chip platforms.
Vertical-Cavity Surface-Emitting Lasers Vertical-Cavity Surface-Emitting Lasers (VCSELs) achieve the lowest power consumption of any electrically driven lasers; with typical threshold currents between 0.5 and 1.0 mA and operating voltages less than 2 V they can run continuously on two AA batteries for several months. Other desirable attributes of VCSELs are high modulation bandwidth (10 GHz typical), circular output beam for coupling to optical fibers, high electron-to-photon differential quantum efficiency (50% typical), inherent single-longitudinal-frequency mode operation, and small cavity volume (a cylinder approximately 8 microns tall and 8 microns in diameter). These properties make VCSELs highly attractive for low-power optical microsystems that include: lasers, lenses and other optical elements, photodiodes, and standard integrated circuits for laser driving and photodiode sensing. The images below show a single-frequency 850-nm VCSEL driven at 2 mA and its properties (output optical power and voltage drop) versus drive current from 0 to 6 mA, exhibiting a threshold current of 0.9 mA.
Sandia has a unique ability to develop novel VCSEL devices using proprietary research capabilities developed over the past 20 years that are not commercially available. Sandia has been recognized as a leader in VCSEL research since the early 1990s, with over 1000 research publications and an extensive portfolio of intellectual property. The VCSEL research activity at Sandia is vertically integrated, with a unique breadth of in-house capabilities spanning VCSEL design, modeling, epitaxial semiconductor growth, cleanroom microfabrication, electrical characterization, optical characterization, and heterogeneous microsystem integration. Most recently, Sandia has developed single-frequency tunable VCSELs for atomic spectroscopy and MEMS interferometer sensors, spanning a range of custom wavelengths from 750 to 1050nm.
Focal Plane Arrays
Sandia National Laboratories has a long history and expertise in the development and demonstration of advanced infrared focal plane array (FPA) materials, devices, and data processing. Current R&D projects are centered on nBn FPAs in the shortwave, mid-wave, and long-wave infrared bands, leveraging novel III-V materials in phosphides and antimonides. Sandia has consistently demonstrated the highest material and device performance and is leading the development of cutting-edge infrared sensors, pushing the envelope of resolution and performance. Furthermore, advanced photonic integration concepts and methods are being developed to realize greater functionality of infrared sensors, such as agile spectral sensing and hyperspectral imaging, to enhance mission quality while driving down size, weight, power, and cost. Capabilities include multiple molecular-beam epitaxy reactors, large-format FPA fabrication/hybridization, and advanced nanoscale lithography.
Fabrication FacilitiesFabrication leverages the Sandia MESA MicroFab facility for III-V semiconductor electronics and photonics. This comprises a 16,600 sq ft class-10 cleanroom with capabilities spanning semiconductor crystal growth, complete processing with state-of-art direct-write electron-beam and projection stepper lithography with 2-6 inch wafer handling. The facility represents a Department of Energy investment in the creation, development, and prototyping of optoelectronics spanning TRL1-6+. Portions of the MESAFAB activity are compliant to NNSA QMS/QC-1/10 requirements, and a subset of this is Defense Microelectronics Activity (DMEA) certified as Trusted.
High Speed Digital Optical Systems
Figure 1 - (a) All-optical Logic Gate, and (b) 40 Gb/s eye from waveguide PD receiver
Recent Sandia programs in high-speed digital optical data COM communications are illustrated by the pair of images above showing an all-optical logic PIC performing a logical NOT function at 40 Gb/s. On this PIC an optical fiber data stream is input at the lower left corner. The data is optically amplified and then the inverse data (NOT output) transferred to an output optical beam sourced from the on-chip distributed Bragg reflection (DBR) laser and sent out of the PIC at the right edge. At right is a 40 Gb/s eye diagram taken from a high-speed waveguide photodiode exhibiting 40 mW input optical saturation power.
Radio Frequency Photonics
Another Sandia PIC development project is a highly functional PIC for the channelization of wideband radio frequency (RF) signals. The image above shows the PIC with illustrated input and output signals. This monolithic InP PIC integrates low-loss optical ring resonator filters with an on-chip wavelength tunable DBR laser to achieve parallel notch filtering (channelizing) in the optical domain of an input RF signal. Filters are 1-3 GHz wide. This optical domain RF filter function built into the PIC enables a dramatic reduction in size, weight and power compared to conventional electronics.
The final example, shown above, is the Sandia PIC using mutual injection locking of monolithically integrated coupled-cavity DBR lasers and modulators to exploit on-chip optical coupling to push the data modulation bandwidth of coupled lasers well beyond the fundamental limits of individual lasers. In this case, the coupled laser PIC is capable of modulation beyond 40 GHz where the individual lasers function only to ~3 GHz.
The silicon photonics process is an electro-optical silicon photonic integrated circuit platform built on silicon on insulator (SOI) wafer technology with fully integrated Ge detectors.
Figure 1 Illustration of Sandia’s MESA facilities and capabilities
Leveraging the extensive CMOS production fabrication and testing capabilities in Sandia’s MESA facility (Figure 1), over the past 8 years, Sandia has engineered a mature silicon photonics process (see Figure 2). The silicon photonics process is an electro-optical silicon photonic integrated circuit platform built on silicon on insulator (SOI) wafer technology. The platform includes two waveguide interconnect layers (in silicon and silicon nitride), a full suite of dopant implants to provide active p-n junction formation and low ohmic contacts, and metal interconnect with optical cladding layers. Sandia’s silicon photonic process represents a mature process technology upon which to develop novel photonic integrated circuits and systems. This silicon photonics process has enabled numerous best in class device demonstrations, including record lowest energy optical modulators, record high speed Ge photodiodes, high speed optical modulators and resonant frequency locking of microring resonator filters and modulators.
Figure 2 Overview of the silicon photonics process at the MESA fabrication facility
Figure 3 Ring resonator filters and Ge detector grown on Si waveguide cross section
Using the existing silicon photonics platform, Sandia has demonstrated many leading-edge silicon photonics devices for applications in communications, sensing, and computing. Among the highlights:
- The lowest energy resonant modulator at < 1 fJ/bit
- Full telecommunications C-band tunable resonant second-order filters
- Reconfigurable 2 x 2 wavelength selective switches and broadband switches with nano-second and sub-nanosecond switching times, integration of a micro-heater, sensor and modulator which were used to demonstrate thermal stabilization of resonant wavelength over 55C using scalable wavelength locking techniques
- Demonstration of an ultra-low V-pi*length product of < 1V-cm in a 10 Gb/s Mach Zehnder modulator and modulators with 3 dB bandwidths above 20 GHz
- Demonstration of an error free ‘long haul’ communications link using silicon photonics resonant modulators over 70 km
- Measurement and analysis of uniformity of manufactured resonant wavelength
- Ultra-sensitive room temperature infrared sensors with 1550 nm optical readout
- Low voltage compact broadband phase modulators and 2 x 2 thermo-optic switches
- Silicon photonics modulators with our strategic radiation-hardened 0.35 um CMOS, demonstrating a 2 Gb/s modulator driver and resonant modulator
- Record 45 GHz bandwidth Germanium detectors in Sandia's silicon photonics process
Sandia has developed new processes for fabricating suspended active silicon photonic structures and is also making important contributions to the theory and demonstration of nanoscale optomechanical and phononic crystal devices, where the nanoscale light-matter within waveguides and other structures are opening new doors for ultra-high frequency transduction, sensing, and signal processing.
Figure 4 Balanced Homodyne Detector based Modulator Stabilization System
In 2014, Sandia successfully delivered hundreds of Si photonics dies to four universities that are part of the National Science Foundation’s Engineering Research Center for Integrated Access Networks (CIAN). In this first multi-project run with external collaborators, Sandia offered reticle space alongside its photonic designs. A Sandia Silicon Photonic Design Manual, as well as programming scripts for design and layout, were provided to the MPW users prior to the layout submission, enabling them to create custom photonics designs and take full advantage of existing device designs and smooth reticle integration. Sandia is open to partnering with other interested parties in developing a Si photonics design kit (PDK) that supports the IMI community. Sandia also invites discussions with commercial foundries interested in adopting the Sandia Silicon Photonics Process technology for high-volume production to support IMI.
Figure 5 Si Photonics Multi-user project chip
Sandia has conducted many past and active R&D programs in the broad area of silicon-based photonics with scientific, national security, and commercial interests. The Sandia photonics team is currently leading a large internal R&D program in Quantum Communications with a goal to demonstrate a quantum key distribution (QKD) network with chip-scale transceiver nodes. The team recently completed a large project in exascale computing, to demonstrate low-energy silicon photonic transceivers with integration of state-of-the-art digital electronics. Other related efforts include Laboratory Directed Research & Development (LDRD) projects to integrate silicon photonics with focal plane arrays to enhance communication bandwidth and performance.
Sandia has supported many DOD efforts such as DARPA programs for Si Photonics for on-chip communications (UNIC), ultra-low power switching (ZOE), chip-scale optical phased arrays (SWEEPER), and optomechanical RF Photonics (MESO). This extensive national resource in Silicon photonics is available to collaborate with commercial and university partners in overcoming unique photonics challenges, productizing technologies from Sandia’s research efforts, and leveraging over 25 issued and pending patents.
Sandia has unique capabilities in hybrid integration of custom photonic devices and advanced electronic circuits, enabling prototyping of high-performance optoelectronic systems and microsensors.
Enabling Photonic/Electronic MicrosystemsSandia National Laboratories has developed several state-of-art hybridization capabilities to enable prototyping of high performance optoelectronic systems and microsensors for national security applications. Intimate integration of dissimilar materials allows the use of optimized photonic devices, optical elements, and electronic circuitry while improving overall system performance compared to conventional packaging approaches.
Heterogeneous integration processes leverage the Sandia MESA MicroFab facility, a 16,600sq-ft class-10 cleanroom with an extensive microfabrication tool set. Relevant integration methods range from wafer bonding of materials prior to microfabrication, to precision flip-chip attach of devices after processing is completed. Microsystems targeting a wide range of applications have been demonstrated, combining materials such as silicon, InP, GaAs, GaSb, AlN, diamond, and glass.
Example Applications Enabled by Heterogeneous Integration
Sandia experts have decades of experience with the microsystems packaging process, a key step in successful development of integrated systems.
Advanced PackagingThe development of enabling photonic/electronic microsystems requires more than the invention of new and unique devices and structures. These devices must be individually packaged and interconnected to function together as an integrated system that can communicate effectively with the macro external world. One must understand the application requirements to anticipate and address a number of multidisciplinary engineering challenges. To maximize chances of success, packaging, assembly, and integration should be considered as early as possible.
Sandia staff members have many decades of experience developing not only first-of-a-kind R&D devices, but also high-reliability devices for space and national defense applications, as well as commercial products. Just a sample of recent and current projects includes high-speed, high-resolution X-ray cameras, remote sensors for space deployment, a variety of quantum devices operated at cryogenic temperatures, and autonomous chemical microsensor systems. We can help evaluate a variety of packaging and integration options, anticipating and addressing manufacturability, rework, thermal management, and materials compatibility issues. Strategic partnerships within Sandia as well as with other national laboratories, universities, and private industry enable the development and implementation of advanced microsystems packaging solutions with the greatest value
Trusted Packaging Capabilities
Seal and Encapsulation
Design and Development
Custom Packaging and Assembly
Flip Chip Assembly
Sandia’s mission in national security has fostered capabilities and technologies including Photonics, Photovoltaics, Focal Plane Arrays, Advanced Sensors, Optical MEMS, Plasmonics, and Metamaterials.
Sandia’s mission in national security has fostered capabilities and technologies including Photonics, Photovoltaics, Focal Plane Arrays, Advanced Sensors, Optical MEMS, Plasmonics, and Metamaterials.
These capabilities in photonics support a board range of applications, from remote sensing in space and novel military RF communications to commercial photovoltaics and solid state lighting. Sandia’s research efforts will continue to accelerate innovation in technologies that benefit not only U.S. warfighters, but also the commercial sector. Under the IMI program, Sandia will partner with interested industry and university partners to further advance and maturate photonics technologies that strengthen U.S. security and economic well-being.
- Optical Interconnect for networking, computing, and sensor systems
- Optical Data Links for naval, ground, or space communication
- Infrared Detection for warfighters, homeland security, automotive and aeronautic applications
- Alternative Energy Sources to enable mobility and a clean, sustainable environment
- RF Signal Generation and Detection for radar and wireless communication
- Proximal and Standoff Detection for chemical and biological agents
- High-efficiency and cost-effective lighting
The Silicon Fab has processing expertise in both CMOS and MEMS technologies. Over 150 equipment sets are maintained, supported and operated 24 hours per day, 5 days a week (3 shifts). Both processing and maintenance expertise are staffed on all 3 shifts. Sandia offers unique prototyping capabilities and is capable of producing full flow production lots with quick turnaround time, as well as performing flexible process development.
- High NA 248nm Deep UV Lithography with resolution down to 110nm and Ebeam lithography with 5nm resolution
- Security-based Application-Specific Integrated Circuits (ASICs)
- Trusted Design of Secure Microprocessors
- High-consequence, High-reliability ICs: ICs that cannot fail in extreme environments
- Low-noise Analog Electronics Designs: Low-power and asynchronous designs
- Sensor Readout Electronics (e.g. – Read-out Integrated Circuits for focal plane arrays)
- High voltage and novel MEMS interface electronics
- Special Processor/Accelerator Architecture and Designs
- Fast-turn, Radiation-Hardened Structured ASIC
- Novel Electronic System Modeling, especially for extreme environment reliability
- Prototype Memristor high-density low-power memory and switch matrices
- Prototype Graphene-based transistors, optoelectronics, and thermal interface materials
- Silicon, Optical, and Nano Technology Heteogeneous Integration
Sandia’s III-V Fab offers wide variety of specialty compound semiconductor device technologies:
- Integrated (vertical-cavity surface-emitting lasers, resonant-cavity photodiodes circuits vertical-cavity surface-emitting lasers, resonant-cavity photodiodes (VCSEL-RCPD)
- Photonic integrated circuits (GaAs, InP)
- Planar lightwave circuits (SiON materials set) such as various optical guided-wave filters and switches
- Optical data links
- Micromirror arrays and subsystems for switch matrices and adaptive optics
- Radio-frequency switches and networks that include phase shifters and tunable filters
- Power amplifiers
- Low-noise amplifiers
- Rad-hard heterojunction bipolar transistors
- High-electron mobility transistors
- Wide-bandgap and ultrawide-bandgap power electronics devices
- Compound semiconductor nanowires, quantum dots, and other nanostructures
Sandia fabricates microelectromechanical systems (MEMS) in both the Silicon Fab and the Compound Semiconductor Fab. The capabilities applied to MEMS include:
- Sub-micron photolithography and electron beam lithography
- Wet etch and deep reactive ion etch (DRIE)
- Polysilicon deposition and multilevel, polysilicon surface micromachining
- Deposition and etching of various metals, including aluminum and tungsten
- Deposition and etching of various oxides
- Deposition and etching of various nitrides, including aluminum nitride
We apply these capabilities to make research prototype devices, such as, micro-actuators, inertial and other sensors, and RF filters and oscillators. Sandia's fabrication facilities enable us to integrate MEMS with photonics and other technologies through heterogeneous integration, chip stacking, and wafer-level packaging.
Sandia's Microsystems effort develops sensors and sensor arrays for biological detection.
Acoustic Wave Biosensors
A particular class of devices known as shear horizontal surface (SH-SAW) sensors is well-suited for the detection of biological agents in liquid environments. These devices have the dual advantages of high sensitivity (down to picograms/cm2) and high specificity conferred by biological receptors such as antibodies, peptides, and nucleic acids. Sandia has demonstrated the detection of bacteria, viral particles, and proteins with these sensors. Handheld biodetection systems incorporating these microsensors are under development.
Sandia has developed a miniature acoustic lysing system that rapidly releases nucleic acids and proteins from cellular samples, enabling more efficient DNA sample preparation. The technology provides a fast and reagentless method to produce a continuous source of lysate without harsh chemical agents. The present system uses plastic cartridges to couple the microchannel lysing regions to a standalone acoustic actuator array. The disposable microchannel cartridges are fabricated using layers of mylar and acrylic, which can be built-up to create complex 3D structures.
Sandia is developing a new battlefield adaptable agent detection platform capable of sensing multiple threat agents (chemical, biological and nuclear) simultaneously in diverse media, as well as a performance model of the detection platform. Magnetic microspheres impregnated with chromophoric dyes or Quantum Dots (QD) are used to develop sensitive tests for chem-bio-threat agents (CB-Agent). A variety of magnetic microspheres (µbeads) may be impregnated with QD or dyes for barcoding. The surfaces of the microspheres are functionalized with streptavidin protein. Biotinylated antibodies to various chem-bio-threat agents may then be stably anchored to the µbeads. The ratio of the optical signature (fluorescence, chemiluminescence or absorption) in the presence and absence of the chemical or biological agent is an indicator for a particular agent.
Electrochemical Biosensor Arrays
The reliable and definitive detection of multiple biowarfare agents on a single robust platform would be a significant asset for the defense of our nation and the safeguarding of warfighters. Multiple signature based biosensors can meet this need as they not only allow for multianalyte detection, but also substantially increase confidence in the sensor output as whole cell, genomic, and proteomic data can be interrogated for each target analyte. Sandia has developed a method that allows for controlled and selective immobilization of biorecognition elements onto electrodes, allowing simultaneous multianalyte detection of DNA and proteins.
In medical diagnostics, quick, precise, and accurate results are desirable for point of care use. Harvesting of carbohydrate fuels, glucose, from humans involves the extraction of interstitial fluid (ISF) or blood. Sandia National Laboratories' ElectroNeedles has proven a platform capable of detecting up to 50 individual analytes real-time and in vivo, without causing pain to the patient.
Sandia has developed genetically tailored cells and bio-compatible self-assembly approaches to enable whole cell sensors in patterned fluidic architectures for chemical and biological sensing. Combining genetics and molecular biology techniques, Sandia designed three reporter/promoter constructs that are integrated directly into yeast chromosomes that produce green, cyan, and red fluorescent protein in response to cholera toxin exposure.
Nanostructure-Induced Fluorescence Detection
Geometries of nature are the subject of intense interest to chemists, biologists, physicists and mathematicians. Examples of natural geometries are found in living organisms (sea shells, for example) and among molecular components. Supra-molecular self-assembled aggregates yield interesting geometries through a collection of molecules held together by non-covalent bonds such as electrostatic forces, hydrogen bonding, or hydrophobic interactions, to provide homogeneous or heterogeneous assemblies. Certain cyanine dyes form molecular aggregates that are either the J- or H-type depending on their chemistry and sample milieu. H-aggregates have a blue-shifted absorption band, relative to the monomeric dye absorption wavelength. J-aggregates have a narrower, red-shifted absorption band, compared to the monomer; J-aggregates display sharp, intense fluorescence emission. Spectral properties of J- and H-aggregates make them attractive candidates for developing a variety of chem-bio-sensing applications.
Sandia combined bio-assay technologies with its own state-of-art photonics technologies to develop a compact, planar, arrayable, optically based biosensor with unprecedented sensitivity. The sensor devices, fabricated in Sandia's Microelectronics Development Laboratory, employ guided wave structures enhanced by the addition of ring-resonators. Overall sensitivity is further enhanced by using gold or quantum dot nanoparticles as the attached optical reporter tags to amplify the optical response, with a goal of being able to detect as little as one bound DNA strand.
A significant disadvantage of many biosensors is the requirement of labels or reagents for sensitive and specific biological detection. Sandia has shown that utilization of electrocatalytic nanoparticles allows for reagent-less and highly sensitive protein detection. Sandia is conducting work on electrocatalytic nanoparticles, focusing on the development of reagent-less and label-free methods for biological detection using the unique properties of nanoparticles.
Figure: Approach Sandia developed for electrochemical immunoassay sensing in which Pd NPs can be loaded onto an anti-TNF-a antibody to create an electrocatalytic antibody. Gold particles are first covalently linked to the antibody (step A). These gold nanoparticles then act as a seed for growth of a palladium shell (step B).
Monitoring the immune response in single host cells challenged with pathogens is required in order to understand the stochasticity of immune response in a population of cells. Sandia has developed a microfluidic platform for optical interrogation of an array of single host cells. Additionally, Sandia has developed an electrofluidic platform for impedimetric interrogation of single host cells during pathogenic challenges.
Figure 1: (left) Schematic of the (a) SCA chip fabrication and (b) optical micrograph of the chip. (right) (a-d) Macrophage held in a trap during an exposure to LPS. (e) Fluorescence intensity across the cell and (f) the ratio of nuclear to cytoplasm fluorescence as a function of time.
Figure 2: Electrofluidic platform for impedimetric interrogation of single cells.
Figure 3: (left) Real and imaginary components of the impedance across a single macrophage as a function of time during an LPS challenge. (right) Nyquist plot of the macrophage before and after LPS exposure.
Sandia experts invent, develop and utilize different tools and techniques for root cause failure analysis. Sandia supports its customers throughout the product life cycle.
Failure Analysis, Test, and Reliability Support
Unique expertise to industry standardsSandia’s expertise in novel failure analysis has developed many techniques that are now industry standards. Our mission continues to develop expertise in Si CMOS, III-V, MEMS, and optoelectronics reliability, and both failure and functional analysis throughout the entire product lifecycle.
Techniques and Tools
Trust, Classified, ITAR
A fully trusted accreditation status and limited access control process may both be utilized for national security projects via the MESA facility.