Fabrication of single walled carbon nanotube (SW-CNT) cantilevers for chemical sensing

With the discovery of carbon nanotubes (CNTs), many applications have been implemented based on their unique electronic, mechanical, chemical and optoelectronic properties. One area of applications is in gas sensors for detecting, oxygen, flammable and toxic gases. In our work, the focus is on the fabrication of carbon nanotube (CNT) cantilever sensors for integration with CMOS readout chip which offer increased sensitivity. The higher surface-to-bulk ratio enhances the property and performance of the gas sensor by nanocantilevers. In this work, we present the detection method based on the change in capacitance of the single walled carbon nanotube (SWCNT) cantilever. Carbon nanotubes are capable of interacting with the gaseous species either directly or indirectly by using a polymer analyte coated on its surface. The capacitance variation technique of measuring cantilever deflection was used to measure the bending rate. The capacitance between the cantilever and the fixed electrode varies as a function of the magnitude of the bending of the cantilever which is in turn proportional to the concentration of the gas species in the surrounding environment. To measure the variation in the capacitance value, the CNT cantilever beam is considered as one of the electrodes of the capacitor and the metal film as the other. The air between the plates acts as the dielectric material. Simulations including both ANSYS for nanocantilevers and SPICE for CMOS readout chip and experimental results are presented in this research. Integration and packaging issues are also discussed in our research

Advanced sensors technology survey

This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed

Interface Circuits for Microsensor Integrated Systems

ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms. [Recent advances in sensing technologies, especially those for Microsensor Integrated Systems, have led to several new commercial applications. Among these, low voltage and low power circuit architectures have gained growing attention, being suitable for portable long battery life devices. The aim is to improve the performances of actual interface circuits and systems, both in terms of voltage mode and current mode, in order to overcome the potential problems due to technology scaling and different technology integrations. Related problems, especially those concerning parasitics, lead to a severe interface design attention, especially concerning the analog front-end and novel and smart architecture must be explored and tested, both at simulation and prototype level. Moreover, the growing demand for autonomous systems gets even harder the interface design due to the need of energy-aware cost-effective circuit interfaces integrating, where possible, energy harvesting solutions. The objective of this Special Issue is to explore the potential solutions to overcome actual limitations in sensor interface circuits and systems, especially those for low voltage and low power Microsensor Integrated Systems. The present Special Issue aims to present and highlight the advances and the latest novel and emergent results on this topic, showing best practices, implementations and applications. The Guest Editors invite to submit original research contributions dealing with sensor interfacing related to this specific topic. Additionally, application oriented and review papers are encouraged.

Polymeric Microsensors for Intraoperative Contact Pressure Measurement

Biocompatible sensors have been demonstrated using traditional microfabrication techniques modified for polymer substrates and utilize only materials suitable for implantation or bodily contact. Sensor arrays for the measurement of the load condition of polyethylene spacers in the total knee arthroplasty (TKA) prosthesis have been developed. Arrays of capacitive sensors are used to determine the three-dimensional strain within the polyethylene prosthesis component. Data from these sensors can be used to give researchers a better understanding of component motion, loading, and wear phenomena for a large range of activities. This dissertation demonstrates both analytically and experimentally the fabrication of these sensor arrays using biocompatible polymer substrates and dielectrics while preserving industry-standard microfabrication processing for micron-level resolution. An array of sensors for real-time measurement of pressure profiles is the long-term goal of this research. A custom design using capacitive-based sensors is an excellent selection for such measurement, giving high spatial resolution across the sensing surface and high load resolution for pressures applied normal to that surface while operating at low power

Towards Single-Chip Nano-Systems

Important scientific discoveries are being propelled by the advent of nano-scale sensors that capture weak signals from their environment and pass them to complex instrumentation interface circuits for signal detection and processing. The highlight of this research is to investigate fabrication technologies to integrate such precision equipment with nano-sensors on a single complementary metal oxide semiconductor (CMOS) chip. In this context, several demonstration vehicles are proposed. First, an integration technology suitable for a fully integrated flexible microelectrode array has been proposed. A microelectrode array containing a single temperature sensor has been characterized and the versatility under dry/wet, and relaxed/strained conditions has been verified. On-chip instrumentation amplifier has been utilized to improve the temperature sensitivity of the device. While the flexibility of the array has been confirmed by laminating it on a fixed single cell, future experiments are necessary to confirm application of this device for live cell and tissue measurements. The proposed array can potentially attach itself to the pulsating surface of a single living cell or a network of cells to detect their vital signs

Thin-film piezoelectric-on-substrate resonators and narrowband filters

A new class of micromachined devices called thin-film piezoelectric-on-substrate (TPoS) resonators is introduced, and the performance of these devices in RF and sensor applications is studied. TPoS resonators benefit from high electromechanical coupling of piezoelectric transduction mechanism and superior acoustic properties of a substrate such as single crystal silicon. Therefore, the motional impedance of these resonators are significantly smaller compared to typical capacitively-transduced counterparts while they exhibit relatively high quality factor and power handling and can be operated in air. The combination of all these features suggests TPoS resonators as a viable alternative for current acoustic devices. In this thesis, design and fabrication methods to realize dispersed-frequency lateral-extensional TPoS resonators are discussed. TPoS devices are fabricated on both silicon-on-insulator and thin-film nanocrystalline diamond substrates. The performance of these resonators in simple and low-power oscillators is measured and compared. Furthermore, a unique coupling technique for implementation of high frequency filters is introduced in which dual resonance modes of a single resonant structure are coupled. The measured results of this work show that these filters are suitable candidates for single-chip implementation of multiple-frequency narrow-band filters with high out-of-band rejection in a small footprint.Ph.D.Committee Chair: Farrokh Ayazi; Committee Member: James D. Meindl; Committee Member: John D. Cressler; Committee Member: Nazanin Bassiri-Gharb; Committee Member: Oliver Bran

Solid State Circuits Technologies

The evolution of solid-state circuit technology has a long history within a relatively short period of time. This technology has lead to the modern information society that connects us and tools, a large market, and many types of products and applications. The solid-state circuit technology continuously evolves via breakthroughs and improvements every year. This book is devoted to review and present novel approaches for some of the main issues involved in this exciting and vigorous technology. The book is composed of 22 chapters, written by authors coming from 30 different institutions located in 12 different countries throughout the Americas, Asia and Europe. Thus, reflecting the wide international contribution to the book. The broad range of subjects presented in the book offers a general overview of the main issues in modern solid-state circuit technology. Furthermore, the book offers an in depth analysis on specific subjects for specialists. We believe the book is of great scientific and educational value for many readers. I am profoundly indebted to the support provided by all of those involved in the work. First and foremost I would like to acknowledge and thank the authors who worked hard and generously agreed to share their results and knowledge. Second I would like to express my gratitude to the Intech team that invited me to edit the book and give me their full support and a fruitful experience while working together to combine this book