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The Effect Of Heating Area And Wheatstone Bridge Materials On A Thermally Actuated Mems Viscosity Sensor, Connor Michael Levine

Theses

Being able to accurately measure oil viscosity in real time is critical for multiple applications. It can ensure that the oil being used to protect and lubricate gears and other mechanical elements is good. To do this a thermally actuated micro electromechanical systems (MEMS) based sensor has been previously developed. The sensor is able to measure viscosity by having the fluid couple with the oscillating diaphragm and monitoring the frequency, amplitude and quality factor of the waveform. To improve the accuracy of the sensor, 5 different versions were created to study the effects of heating area and the sensing material …

Hyper-Sensitive Mems Pressure Sensor Array For Microscale Bubble Pressure Measurement, Yash Rajan Rasaikar

Theses

As technology is advancing, more complex, efficient, and powerful devices are being made. These powerful devices generate a lot of heat which needs to be taken out to maximize their performance. Hence, efforts are being made to improve cooling techniques for these devices. Boiling is one such technique used in the cooling of devices. The heat transfer performance in the flow boiling systems is higher than that in pool boiling systems. With a simple add-on tapered manifold over a plain surface, we can convert pool boiling to flow boiling. This study will lead to improved performance and reliability of microelectronic …

Evaluation Of Pixel-Scale Tunable Fabry-Perot Filters For Optical Imaging, Daniel L. Edwards

Theses

The Fabry-Perot interferometer (FPI) is a well-developed and widely used tool to control and measure wavelengths of light. In optical imaging applications, there is often a need for systems with compact, integrated, and widely tunable spectral filtering capabilities. We evaluate the performance of a novel tunable MEMS (Micro-Electro-Mechanical System) Fabry-Perot (FP) filter device intended to be monolithically integrated over each pixel of a focal plane array. This array of individually tunable FPIs have been designed to operate across the visible light spec-trum from 400-750 nm. This design can give rise to a new line of compact spectrometers with fewer moving …

Sensitivity Enhancement Of Metal-Oxide Chemical Sensors For Detection Of Volatile Organic Compounds, John F. Hughes

Theses

Metal-oxide chemical sensor technology has been praised as a cheap and efficient method of detecting both reducing and oxidizing gases depending on the metal-oxide’s carrier type. The research conducted in this thesis explored methods of enhancing the sensitivity of an n-type metal-oxide material (indium tin oxide, ITO) to a volatile organic compound (VOC) through changes in both device and testing characteristics. Two methods of testing prototype sensors were developed which consisted of short and long-term exposure to ethanol at different temperatures and concentrations. Maximum sensitivity at 2000 ppm was achieved in devices with thin, annealed metal-oxide layers with a high …

A Wireless Communication Platform For Mems Sensors, Chen Chen

Theses

Wireless measurement systems combining current advanced information collection, processing and wireless communication technology, have been applied to information measurement in special occasions. As a short range wireless communication technology, bluetooth is low cost, stable, and low power. Bluetooth technology is used in monitoring and wireless control system widely.

ArduinoBT is the bluetooth version of the general Arduino board, which is open source and convenient as a wireless development tool.

This thesis presents a hardware and software experimental wireless platform for the application of multiple kinds of MEMS sensors. By the combination of ArduinoBT and signal conditioning circuit, different types of …

Aluminum Nitride Contour Mode Resonators, Joshua Robert Melnick

Theses

Resonators are a major component in RF electronic products. They are used in a host of ways to filter radio signals. Modern and Future RF communications have placed high demands on the industry; requiring low power usage, wide array of applications and resistance to noise.

In this thesis, a discussion of the motivation for RF MEMS filters and basic theory is given with an explanation of the concepts of Q factor, piezoelectricity, acoustics theory, the major types of resonators (SAW, BAW, CMR or LAMB), apodization theory and techniques as well as design, simulation of CMR and BAW devices, testing and …

Cmos Compatible 3-Axis Magnetic Field Sensor Using Hall Effect Sensing, Joshua R. Locke

Theses

The purpose of this study is to design, fabricate and test a CMOS compatible 3-axis Hall effect sensor capable of detecting the earth’s magnetic field, with strength’s of ~50 μT. Preliminary testing of N-well Van Der Pauw structures using strong neodymium magnets showed proof of concept for hall voltage sensing, however, poor geometry of the structures led to a high offset voltage. A 1-axis Hall effect sensor was designed, fabricated and tested with a sensitivity of 1.12x10-3 mV/Gauss using the RIT metal gate PMOS process. Poor geometry and insufficient design produced an offset voltage of 0.1238 volts in the 1-axis …

Assessing The Performance Of Digital Micromirror Devices For Use In Space-Based Multi-Object Spectrometers, Kenneth Fourspring

Theses

A current need in space-based instrumentation is a reconfigurable slit mask. Several techniques for slit masks have been employed for ground-based astronomical spectrographs. These ground-based instruments have used large discrete components, which are impractical for remote operation in space-based deployment. The Texas Instruments' Digital Micromirror Device (DMD) was originally conceived purely for display purposes, but is a viable candidate to be use as a slit mask in a space-based multi-object spectrograph (MOS). The Integrated Circuit (IC) manufacturing industry has enabled the robust integration of both silicon transistors and Micro-Electrical Mechanical Systems (MEMS) optical components into a very reliable monolithic chip …

Multisensor Mems For Temperature, Relative Humidity, And High-G Shock Monitoring, Daniel Smith

Theses

The use of MEMS (micro-electro-mechanical system) sensors in multiple applications of environmental monitoring help to fill the need of a small scale, low power monitoring and sensing applications. In this design, the use of single-die multiple MEMS sensors to monitor ambient temperature, relative humidity, and accelerative high-g shock were developed and tested. In addition to the sensors, signal conditioning circuits were developed for outputting the sensor data into a microcontroller to analyze and process the signals into useful information for human operators to analyze. The three sensors were fabricated using a bulk micro-machined process on 100mm silicon wafers developed in …

Tunable Micro-Electro Mechanical Fabry Perot Etalon, Annette Rivas

Theses

Many different devices capable of spectral wavelength collection exist. The device we propose is an array of individually tunable MEMS Fabry Perot etalons capable of scanning from 400nm to 750nm as commanded. Typically when Fabry Perot devices are used additional etalons are placed in series to reject extra modes that would otherwise be passed by a single etalon. The device that is examined rejects the extra modes without the need for an extensive filtering scheme because the optical path length is held to ½ wavelength. The device proposed is thermally actuated. It has been modeled in COMSOL and shows even …

A Thermally Actuated Microelectromechanical (Mems) Device For Measuring Viscosity, Ivan Puchades

Theses

A thermally actuated non-cantilever-beam micro-electro-mechanical viscosity sensor is presented. The proposed device is based on thermally induced vibrations of a silicon-based membrane and its damping due to the surrounding fluid. This vibration viscometer device utilizes thermal actuation through an in-situ resistive heater and piezoresistive sensing, both of which utilize CMOS compatible materials leading to an inexpensive and reliable system. Due to the nature of the actuation, thermal analysis was performed utilizing PN diodes embedded in the silicon membrane to monitor its temperature. This analysis determined the minimum heater voltage pulse amplitude and time in order to prevent heat loss to …

Design And Fabrication Of Structured Roughnesses In Microchannels With Integrated Mems Pressure Sensors, Tushara Pasupuleti

Theses

As the demand for cooling is increased for high-density powered electronic devices, researchers have proposed solutions to improve the efficiency of the microchannel liquid cooling system to meet these requirements. Introducing roughness in the microchannels is one of the approaches to enhance the heat transfer. The fluid flow behavior needs experimental investigation before exploring the heat transfer efficiency. A test structure consisting MEMS pressure sensors were fabricated along the length of the microchannel. Smooth microchannels and rough microchannels with structured roughness were fabricated. A fabrication process flow has been developed to fabricate the microchannel and the pressure sensor on the …

A Multi-Sensor Chip For Monitoring The Quality Of Drinking Water, Heidi Purrington

Theses

A MEMS based multi-sensor chip has been developed for the purpose of monitoring turbidity, TDS, and temperature in a sample of drinking water. The benefits of MEMS technology over conventional sensors include compact size, low power consumption, integration capability, and low cost bulk manufacturing. Two revisions of the multi-sensor silicon chip were designed, fabricated, and tested. The layout of the chip and the fabrication process were redesigned in the second spin to provide more robust and sensitive responses. The sensor structures include photodiodes, temperature diodes, interdigitated electrodes in direct contact with the sample, and capacitive interdigitated fingers. The sensors were …

A Two Degrees-Of-Freedom (Dof) Scanning Micromirror Using Thermocapillary Effect In Microdroplets, Rakesh Dhull

Theses

This thesis research proposes a novel and simple means of tilting micromirror on a microdroplet by utilizing thermocapillary actuated droplet deformation. Device theory, device design, fabrication, packaging, testing and results are discussed to demonstrate the operation of a 2-degrees-of-freedom (2- DOF) scanning micromirror. Thermocapillary, or Marangoni, effect and contact angle hysteresis are employed to control the droplet shape and position. Hysteresis in different liquids is studied with its influence on the stability of the droplet. The device consists of a micromirror placed onto a microdroplet, and can produce a 6.5° tilting angle when actuated at 30 V. The tilting angle …

Development Of A Three-Axis Mems Accelerometer, Jacob Leveto

Theses

While originally developed to deploy air bags for the automotive industry, Microelectromechanical Systems (MEMS) based accelerometers have found their way into everything from video game controllers to cells phones. As prices drop and capabilities improve, it is expected that the use of accelerometers will further expand in the coming years. Accelerometers currently have the second highest MEMS sales volume, trailing only pressure sensors [1]. In this work several single and three-axis accelerometers are designed, fabricated, and tested under a variety of conditions. The designed accelerometers are all based off of the piezoresistive effect, where the value of a resistor changes …

Ion-Sensitive Field Effect Transistor (Isfet) For Mems Multisensory Chips At Rit, Murat Baylav

Theses

This study involves the design and fabrication of an Ion-Sensitive Field Effect Transistor (ISFET), which is aimed to be incorporated into the multisensory chips fabricated at RIT. ISFETs are used for various purposes in biomedical, medicine, and chemical applications and have advantages such as small size, low power consumption, robustness, and fast response time, over the ion-selective electrode (ISE) counterparts. The capability of fabricating ISFETs in a standard CMOS process let them to be used in sensor systems together with the dedicated signal processing circuitry which in turn makes portable applications possible. The ISFET fabricated in this study have a …

Microplasma Mems Device: Its Design, Fabrication And Application In Hydrogen Generation For Fuel Cells, Bindumadhav Sabnavis

Theses

This project presents the design, fabrication, characterization and applications of a MEMS (Micro-Electro-Mechanical Systems) device that generates microplasma at atmospheric pressure. Two types of the devices were conceived, characterized and tested while different carrier gases were employed. The device performance was first characterized by current-voltage (I-V) measurements. A mixture of carrier gas and water vapor was then introduced; the gas resultants were analyzed with Optical Emission Spectroscopy (OES). The spectra shows atomic hydrogen peaks, as the evidence that the microplasma dissociates hydrogen from water vapor. The resultants from the device were sent to a PEM hydrogen fuel cell for the …

Microgripper Force Feedback Integration Using Piezoresistive Cantilever Structure, Todd R. Simon

Theses

Force feedback is an important feature in most microgripper applications, but it is commonly overlooked. To successfully implement this feature, a cantilever structure has been designed and fabricated to integrate force feedback into a microhand gripper. The piezoresistive properties of doped polysilicon are used to transduce the mechanical stress of an object pressing against the cantilever sensor, resulting in a change in resistance or voltage capable of being monitored with external hardware. The force sensing structure was designed to have a fabrication process compatible with that of the microhand, allowing for their eventual integration. This fabrication process uses both bulk …

Analysis Of Effective Mechanical Properties Of Thin Films Used In Microelectromechanical Systems, Ajay Pasupuleti

Theses

This research aims at analyzing the effective mechanical properties of thin film materials that are used in MEMS. Using the effective mechanical properties, reliable simulations of new or slightly altered designs can be performed successfully. The main reason for investigating effective material properties of MEMS devices is that the existing techniques can not provide consistent prediction of the mechanical properties without time-consuming and costly physical prototyping if the device or the fabrication recipe is slightly altered. To achieve this goal, two approaches were investigated: soft computing and analytical. In the soft computing approach, the effective material properties are empirically modeled …

Development Of A Porous Silicon Flow-Through Field Effect Sensing System For Chemical And Biological Detection, Jeffrey Clarkson

Theses

With an increasing need for homeland security, and breakthrough advancements in sensing applications, the demand for highly sensitive, compact, biological and chemical sensing devices is evident. Macroporous silicon (MPS) is an ideal material for meeting these demands because it exhibits a large degree of internal surface area and is fully compatible with silicon technologies. Since the surface is sensitive to charged molecules, localized field effects from analytes interfaced with MPS will cause modulation of a space charge region in the semiconductor. In this work, a porous silicon based sensing system is designed, fabricated, and characterized. The unique properties of porous …