Publications

A Micro-Electro-Mechanical Systems (MEMS) Device to Measure the Fracture Strain of Polycrystalline Silicon

Peter Truxtun Jones
Roger T. Howe
1995

The past decade has witnessed the establishment of a new field of technology concerned with the manufacture of microscopic sensors and actuators, known as Micro-Electro-Mechanical-Systems (MEMS). The field of MEMS is based on the use of integrated circuit fabrication techniques to create...

A MEMS Thin Film AlN Supercritical Carbon Dioxide Valve

Ya-Mei Chen
Albert P. Pisano
Liwei Lin
Tsu-Jae King Liu
Tarek Zohdi
2011
In this thesis, a new piezoelectric valve system with bi-chevron aluminum nitride (AlN) actuator is described. The intended application of the new piezoelectric valve is for the advanced printing technology with supercritical carbon dioxide as the solvent. With supercritical carbon dioxide as the solvent, the ink dissolved will start to nucleate with a micronozzle and generate extremely small and uniform ink particles due to rapid expansion of supercritical...

A Silicon-Based Microsensor to Measure Airborne Contaminants

Bharat M. Shah
Richard M. White
Albert P. Pisano
1994

In this reseach project the ability of a microfabricated acoustic-wave microsensor to detect volatile organic compounds in indoor air was studied. The microsensors were made in the Berkeley Microfabrication facility following designs developed at the Berkeley Sensor & Actuator Center. The devices were exposed in a four-liter chamber to vapor-phase concentrations of six representative VOCs one at a time: tetrachloroethylene, 1,1,1-trichloroethane, toluene, benzene, ethanol, and formaldehyde. The device sesnitivity to each VOC was computed from the measured oscillator frequency and...

A Multi-Stage Micro-Tangential Flow Filtration System for BioMEMS Applications

Patrick Pak-Ho Leung
Dorian Liepmann
Luke P. Lee
Liwei Lin
2002

The micromachining technology that emerged in the 1980s has yielded an explosion of developments of micro electromeclianica1 systems (MEMS) in the past two decades. The developments have brought lives to many miniaturized sensors and...

A MEMS Sensor for AC Electric Current

Eli Sidney Leland
Paul K. Wright
Richard M. White
Dennis K. Lieu
2009
This manuscript describes the development of a new MEMS sensor for the measurement of AC electric current. The sensor is comprised of a MEMS piezoelectric cantilever with a microscale permanent magnet mounted to the cantilever’s free end. When placed near a wire carrying AC current, the magnet couples to the oscillating magnetic field surrounding the wire, causing the cantilever to deflect, and piezoelectric coupling produces a sinusoidal voltage proportional to the current in the wire. The sensor is itself...

Miniature Gaseous Light Sources

Hsi-Jen Yeh
Richard S. Muller
Roger T. Howe
1991

This report describes miniature gas-filled plasma-discharge cavities fabricated using combined surface and subsurface micromachining. Starting with a bare silicon substrate, successive layers of polycrystalline silicon, low-stress silicon nitride, and low-temperature oxide layers were deposited to form the micro cavities. Polysilicon electrodes were patterned to serve as electrical connections to the gas. Low-stress silicon nitride formed the insulating layer and the cavity wall which confined neon at atmospheric pressure. Low-temperature oxide served as the sacrificial layer which defined...

Microstructure Micropackaging

Kristen M. McNair
Roger T. Howe
Richard M. White
1991

Two processes are developed to fabricate electrostatic comb drives hermetically encapsualted in a silicon nitride or polysilicon micropackage. To fabricate the silicon nitride micropackage, high-doped phosphosilicate glass is deposited, after the electrostatic comb-drive process is complete except for the release etch, and reflowed to form a mould for the silicon nitride microshell. The mould is patterned with a 5:1 BHF wet etch, and then the etch channel layer of phosphosilicate glass is deposited and patterned with a wt etch. The silicon nitride microshell layer is depositied, and holes...

Micromechanical Electrostatic Voltmeter

Charles Heng-Yuan Hsu
Richard S. Muller
Roger T. Howe
1991

A microminiature, noncontracting electrostatic voltmeter (ESV), produced by IC processes on a silicon wafer, is described. The ESV works on the principle of intermittent shuttering and exposing a sensing electrode to an electric field between a remote electrode at a different potential from the sensing electrode. The resultant time-varying field at the electrode produces an electrical signal. The principle of ESV measurements by intermittent shuttering is well establihsed and hybrid designs are presently used commerically. This invention teaches how the entire structure, and eventually the...

Growth Stresses in Undoped LPCVD Polycrystalline Silicon Films

Peter Krulevitch
1991
Thin films have applications in many technological fields, particularly in the area of electronics, where they form the basis of integrated circuits [l]. More recently, the techniques used to manufacture VLSI circuits have been applied to mechanical systems, such as...

Analysis and Characterization of the Vertical Carrier Domain Magnetometer

Bret S. Burns
Richard S. Muller
Roger T. Howe
1989
The point of semiconductor device analysis is to find useful predictors of device performance. With these we can design to specifications, uncover promising directions for improving device operation, and understand device limitations. An actual device has no...