Distributed Microsystems Laboratory: Developing Microsystems that Make Sense Goals: To perform true systems integration for existing or incrementally advanced sensor technologies in such a way as to meet system-level constraints related to: power consumption robustness in real-world environments auto-calibration capability small size, portable deployment self-diagnostic capability multi-stimulus detection sensitivity limits without sacrificing stimulus recognition capability

Distributed Microsystems Laboratory: Developing Microsystems that Make Sense Areas of Research in Microsystems Development Chemical Sensing Microsystems Modeling of front-end olfaction in sensor array design and architecture to enhance system robustness, resilience to broken sensors, auto-calibration capability, and sensitivity floor (detection limit). Streamlining of signal processing to adapt chemical discrimination algorithms to lower-overhead equivalents for implementation in portable systems Sensor platform development for extraction of multiple features from a single micro-sensor in an array (including instrument development) Miniaturization of existing larger chemical sensors and systems Optimization of signal conditioning and readout circuits to reduce superfluous information and enhance signal-to-noise ratios

Distributed Microsystems Laboratory: Developing Microsystems that Make Sense Areas of Research in Microsystems Development Chemical Sensing Microsystems: Available Sensor Technologies ChemFETs: streamlined signal processing, sensor platform development, miniaturization of systems, optimization of signal conditioning. Composite Polymer Sensors: olfactory modeling, streamlined signal processing, sensor platform development, miniaturization Metal-oxide Sensors: olfactory modeling, sensor platform development SPR (surface plasmon resonance): streamlined signal processing; miniaturization of systems

Distributed Microsystems Laboratory: Developing Microsystems that Make Sense Areas of Research in Microsystems Development Other Microsystems Development of application specific integrated CMOS imagers and auditory systems modeled after biology Development of imaging and auditory microsystems for streamlined, low-power implementation Development of integrated pressure sensors for characterizing and controlling biopsy sample preparation Development of integrated platforms for evaluating fluorescence of living, dead, and lysed cells Radio Frequency Identification systems for monitoring health of trees to increase their market value (and thereby decrease the number of trees that need to be cut down).

Distributed Microsystems Laboratory: Developing Microsystems that Make Sense What Drives Research in this Laboratory? (e.g. the Vision) LINK TO INDUSTRY: THE APPLICATIONS Environment Environmental monitoring and remediation (groundwater and airborne pollutants) Protecting health and welfare of human beings Chemical and Biological Warfare Sensor Systems useful for widespread distributed implementation Improved Sensor Systems for Biomedical Research ENGINEERING PERSPECTIVE: SYSTEMS INTEGRATION MAUV SCIENCE PERSPECTIVE: MODELLING OF BIOLOGY Olfactory, Auditory, and Vision Modelling

Distributed Microsystems Laboratory: Developing Microsystems that Make Sense What Drives Research in this Laboratory? (e.g. the Vision) PERSONAL PERSPECTIVE AND CONVICTIONS Teaching “Classes”: critical thinking are weighted as heavily as topical skills “Laboratory”: teamwork, maturity and responsibility, long-term potential and vision of students should be developed with as much seriousness as the topical experience. Don’t clone graduate students! Use (constructive) criticism and high expectations as a tool to driving students toward reaching their potential. Research: No weapons of mass destruction ever Keep “making the world a better place” at the top of the priority list Service: Be kind, give easily, don’t get overextended.

SPR (Surface Plasmon Resonance) Chemical Sensing Microsystems Collaboration with Karl Booksh, Department of Chemistry, Arizona State University Polychromatic Light Inlet Port Outlet Port Chemically sensitive coating Gold Interface layer Waveguide Dielectric Color Filter Photodiode Silicon Substrate

SPR (Surface Plasmon Resonance) Chemical Sensing Microsystems Chemically sensitive coating Waveguide Gold Interface layer Analog Photodiode Outputs time Digital Alarm Outputs

Chemical Sensing MicroSystems: Modeled after Front-End Olfaction Incoming Airflow Vapor Sample Incoming Airflow Vapor Sample Heater Chemically Sensitive Coating Pre-concentrator Microcontroller: Streamlined Pattern Recognition (low-power) Aggregation Signal Conditioning Signal Screening Heater Control A/D Conversion (as needed) Metal-oxide or Conducting Polymer

Chemical Sensing Systems: What does front-end olfaction tell us? Source: Kendall and Schwartz; Principles of Neural Science Fact: Olfactory Mucous pre- concentration ignores odors beyond a saturation level and below a threshold level Engineering Implication: concentration detection and odor discrimination should be performed independent of one other

Scale-Invariant A/D Conversion applied to a CMOS Imager n System Architecture Photodiode/transistor Focal Plane Processing, Integrating/Reset Circuits Pixel Selection, Digital Readout Circuits, Readout Amplifiers Global Communication (for automatic gain control), Control/Readout Lines

Scale-Invariant A/D Conversion applied to a CMOS Imager n Ratio-based A/D Conversion: Example 75/25 high/low Original Image 50/50 high/low 25/75 high/low 2-bit converted image

Chemical Sensing Microsystems: Scaling Down Larger Systems Scale: centimeter-size Capteur sensors to micron-size sensors Additional capability: two electrode widths determine whether analyte penetrates into the bulk or remains on the surface of the sensor; provides additional information with which to discriminate analytes Performance Improvements: lower power, faster response time for both sensors and sensor heaters

Chemical Sensing Microsystems: Overcoming CMOS Compatibility Issues Problem: surface non-uniformity causes non-uniform chemical sensing film deposition Solution: use vertical sidewalls as sensor surface coatings Problem: conventional silicon direction-selective etching attacks bonding pads and other exposed aluminum Solution: use different sensor platform architectures that enable dry, isotropic etch