Roger T. Howe (Advisor)

RTH/JDK2: Biomimetic Nanofabrication of Silica Structures Based on Diatoms

William J. Holtz
2006

Diatoms are a type of brown algae that create hydrated silicon-dioxide structures with feature sizes down to 5 nm at ambient temperature and pressure. The goal of this project is to replicate these processes in vitro and then manipulate the process parameters to create engineered structures.

Project end date: 01/09/06

BPN318: SiGe Processing for the Fabrication of a Floating Electromechanical System (FLEMS) Gyroscope

Marie-Ange Eyoum
David Garmire
2006

The long term range of this project was to demonstrate fabrication and control of a potential integrated FLEMS (Floating Electromechanical) Gyro using SiGe MEMS Technology. The sensor system is comprised of a disk-shaped proof mass that is to be electrostatically suspended between sense and drive electrodes located above, below, and at the sides of the disk. An attractive feature of this design is that the proof mass is not structurally linked via suspension, so that mechanical losses associated with anchors are eliminated

Project end date: 08/02/06

RTH/JDK3: Diatom-Inspired Microfluidic Generation of Tunable Emulsions for Macroporous Silica

Frank J. Zendejas
2006

Diatoms are unicellular algae that exhibit exquisite silica cell walls, frustules, made of amorphous silica. Research has shown that diatoms are capable of controlled precipitation of silica during cell division within a specialized membrane called the silica deposition vesicle (SDV). The precipitated silica forms the new shell for the daughter cell. It has been postulated that the diatom SDV contains an emulsion of organic macromolecules arranged in a regular pattern which serve as a template onto which silica is precipitated. Our goal of this project is to use a specially designed...

RTH46/JD: MEMS Resonator Simulation

David Bindel
Emmanuel Quevy
Tsuyoshi Koyama
Wei He
2006

Electromechanical resonators and filters, such as quartz, ceramic, and surface-acoustic wave devices, are important signal-processing elements in communication systems. Over the past decade, there has been substantial progress in developing new types of miniaturized electromechanical resonators using microfabrication processes. For these micro-resonators to be viable, they must have high and predictable quality factors (Q). Depending on scale and geometry, the energy losses that lower Q may come from material damping, thermoelastic damping, air damping, or radiation of elastic waves...

RTH35: Novel SiGe Processes for Electrostatically Actuated MEMS Resonators

Carrie Low
2006

As an alternative material for surface micromachining, polycrystalline silicon-germanium (poly-SiGe) has comparable processes and material properties to polycrystalline silicon (poly-Si). Its low processing temperature is the major advantage of poly-SiGe as it enables post-CMOS integration of MEMS. This modular approach to MEMS integration is an attractive route to higher performance and lower cost microsystems.

Project end date: 01/24/07

RTH29: Lateral-Mode NEMS Resonators Using Internal Electrostatic Transduction

Hei Kam
2006

Electrostatic MEMS resonators show great promise for RF front end applications. Their high motional resistance, however, is one of the major problems for their widespread applications. In this project, we aim to reduce such resistance by using high K dielectric instead of air gaps for transduction. Prototype devices are now being fabricated and will be characterize to see the improvements in performance.

Project end date: 01/24/07

RM5/RTH: Silicon carbide process development and characterization for harsh-environment sensors

Jingchun Zhang
Carlo Carraro
2007

Silicon carbide (SiC) is a wide band gap semiconductor with extraordinary properties and has attracted considerable attention for high temperature electronics. Recently, this material is being pursued for microelectromechanical systems (MEMS) applications in harsh environments. The goal of this project is to develop a series of SiC-based sensors and to characterize them for harsh environments. In order to achieve thisgoal, a series of microfabrication technologies including low-temperature CVD, reactive ion etching, and metalization of poly-SiC films need to be developed. In addition...

RTH42: Nanowire-Coupled Resonators

Noel Arellano
2007

We have developed fabrication processes to create top down nanowire coupled resonators. The critical dimensions were defined using a combination of iline lithography, photoresist ashing techniques and focused ion beam trimming. Nanowires are used as mechanical elements to demonstrate low velocity and maximum velocity coupling. We have also demonstrated an bottom up/ top down integrated fabrication process. Features for the top down segment of the fabrication process are aligned to (111) flat on a (110) SOI wafer. A gold based galvanic displacement method selectively deposits catalyst...

RTH45: Synchronization and interaction of MEMS oscillators

Peter Chen
Donovan Lee
2005

With MEMS oscillators realized frequently in research, and nanoscale resonators around the corner, it is now not only feasible but interesting to have multiple oscillators integrated on one chip. However, the possible mechanical and electrical interactions between closely-placed devices have not been investigated. Recent surges in mathematical research have shown that it is not only possible to achieve synchronization between coupled oscillators; it is also possible to provide a computational solution with a larger array of coupled oscillators. In the MEMS world, this translates into...

RM7/RTH: Dedicated SiC MEMS LPCVD Reactor for Access through the DARPA MEMS Exchange Program

Christopher S. Roper
2007

This project seeks to make Silicon Carbide thin films available to MEMS researchers and designers. A process developed in the Maboudian Lab at UC Berkeley which currently accommodates 2-inch wafers will be scaled up to accommodate 4- and 6-inch wafers. High quality poly-crystalline 3C-SiC films deposited at reasonable growth rates, with controlled residual stress, controlled strain gradient, controlled resistivity, and high uniformity will be sought. Once films with high overall quality and repeatability are grown the process will be released to the MEMS community.

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