Physical Sensors & Devices

Research that includes:

  • Silicon MEMS actuators: comb, electro-thermal, and plastic deformation
  • Precision electronic sensing and measurements of capacitive, frequency, and coulombic MEMS variables
  • Structures and architectures for gyroscopes, accelerometers, micro strain gauges for direct application to rigid structures e.g., steel, and levitated MEMS

Scalable Ultra Low-Power Chemical Sensing with Metal-Organic Frameworks

David Gardner
Xiang Gao
Hossain M. Fahad
An-Ting Yang
Sam He
Ali Javey
Carlo Carraro
Roya Maboudian

This paper reports the innovative use of a highly tunable material, metal-organic frameworks (MOFs), for chemical sensing on an ultra-low-power platform based on a field-effect transistor. We demonstrate proof-of-principle devices functionalized with two MOFs: "HKUST-1" for humidity sensing and "ZIF-8" for reversible NO 2 detection. These devices show minimal drift, yield highly reproducible responses, recover rapidly, and have excellent selectivity. Through this approach, devices with minimal power draw and high selectivity could be widely distributed for continuous environmental and...

Amine-Functionalized Metal-Organic Framework ZIF-8 toward Colorimetric CO2 Sensing in Indoor Air Environment

Adrian K. Davey
Xiang Gao
Yong Xia
Zhou Li
Matthew N. Dods
Steven DelaCruz
Aifei Pan
Sanket Swamy
David Gardner
Carlo Carraro
Roya Maboudian

Carbon dioxide (CO2) has been shown to contribute to human health consequences indoors, such as shortness of breath, nasal and optic irritation, dizziness, and nausea. In this work, we explore the potential of metal–organic frameworks (MOFs) as highly-porous, crystalline sorbents for sensitive colorimetric CO2 detection. In particular, the zeolitic imidazolate framework (ZIF-8) is chosen as the sorptive material due to its chemical stability and tunable CO2 affinity. The colorimetric gas sensor is developed in methanol with three components: (i) MOF ZIF-8 as a high surface area adsorbent...

APP54: MEMS Strain Gauge on Steel: Testing Localized Silicon-Steel Bonds

Theodore Prescop

A rapid bonding process for installing vacuum sealed MEMS strain sensor modules to mechanical components is being developed. This innovative process will be developed to replace conventional adhesive-based approaches. In particular, the silicon to steel bond must achieve these stringent requirements: long life, resistance to chemicals, short bonding process time, and a wide range of storage temperatures. To ensure that the strain within a steel substrate will be accurately measured by the MEMS strain gauge, properties of the bond layer between silicon and steel are observed and...

LWL4: MEMS Sensor for Hard Disk Glide Test

Jongbaeg Kim

Characterization of pitch and roll motions of the slider in the hard disk gimbal system are important parameters in order to achieve higher aerial recording densities. This project describes a novel piezoresistive-type microsensor that could be directly mounted on the existing slider/gimbal system of a hard disk drive to simultaneously measure the pitch and roll angles of the slider.

Project end date: 07/31/03

APP52: MEMS Strain Gauge on Steel: Test Fixture Design

Robert G. Azevedo

The overall project aims to design a MEMS strain gauge that can be bonded directly to steel and accurately measure strain in small strain fields (gauge length of 1 mm or less). In order to verify the group’s designs, I have designed and fabricated a four-point bend test fixture. Strain will be induced in smooth, steel bar stock large enough to allow MEMS and conventional foil strain gauges to be tested simultaneously. The four-point bend test will be used to verify the MEMS strain gauge system-level performance. Further, it will allow comparison of the MEMS gauges to conventional...

BEB6: Electrostatic Actuator Design for a Digital Output Gyroscope

Joseph Seeger

This research investigates the dynamics, design, and control of gap-closing, electrostatic actuators. Because of nonlinearity, gap-closing actuators can give rise to complicated behavior, such as instability, frequency tuning, and parametric resonance. We have demonstrated charge control circuits that stabilize gap-closing actuators and increase the range of motion from 33% of the gap to more than 90% of the gap. We have designed a gyroscope proof-mass with parallel-plate actuators for low voltage oscillation in air with frequency tuning. We have identified parasitic effects, such as...

LWL22: Nanostructure-Based Nanoactuator

Maggie Chau

This project aims to develop nanoactautors based on the actuation of nanostructures such as nanowires and/or nanotubes. With the emerging technology of producing silicon nanowires and carbon nanotubes (CNTs), designing an actuation application would be the next advancement of nanotechnology. This nano actuator will be fabricated by the in-house produced silicon nanowires/carbon nanotubes. Additional processing steps and actuation means will be required to manifest the nanostructures for actuation demonstrations. We intend to investigate related design, process and material issues to...

BEB13: Background Calibration for Low-Power High-Performance A/D Conversion

Boris Murmann

Our project aims to develop and investigate on digital post processing methods and circuit techniques that allow efficient, low power implementation of high performance Analog-to-Digital Converters (ADC) in fine line technologies. The research focuses on a continuous background self-calibration technique applied to a high-speed pipelined ADC topology.

Project end date: 01/25/04

APP53: MEMS Strain Gauge on Steel: Resonant Sensor Design and Fabrication

Julian Lippmann

To fabricate a strain sensor capable of measuring micro-strain (10e-6) with a gauge length no greater then 1 mm. The sensor will be capable of in-situ mounting on pre-existing, minimally treated steel substrates. In addition, the sensor will also have a dynamic range of at least 0-1000 Hz, and maintain sensitivity and linearity over a range of temperatures and environmental conditions. In particular, this project is examining the use of a resonant element (tuning fork) to transduce strain into a electrical signal via capacitive sensing (both comb finger and parallel plate.)...

BEB20: Phase Noise Considerations of a MEMS Oscillator

Manu Seth

Oscillators based on MEMS resonators have been developed but their performance has not been thoroughly investigated. Phase noise has been measured in numerous oscillator designs, but it has not been determined whether these oscillators can meet the specifications of practical applications. This project will attempt to determine some of the limits of MEMS based oscillators in terms of phase noise. I will study the feasibility of using MEMS oscillators as the frequency reference in phase-locked loops. I will then design oscillator circuits meant to minimize noise and meet standard PLL...