Publications

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 Self-Nucleating Evaporator: An Experimental Study of Low-Superheat Pool Boiling via Injection of Gaseous By-Products from the Thermal Decomposition of Azobis-Isobutyronitrile

Christopher William Hogue
Albert P. Pisano
Van P. Carey
2008

For the purpose of exploring a novel heat transfer concept to radically enhance the evaporator performance of the microColumnated Loop Heat Pipe (μLHP) system, an experimental investigation into the feasibility of a lowsuperheat, passive, selfnucleating evaporator surface was performed. The evaporator test surfaces were treated...

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...

A High-Voltage Charge Pump in Bulk CMOS

Eugene Lau Cheung
Bernhard Boser
Albert P. Pisano
1996

The goal of this project is to investigate a circuit for generating 80V in a bulk CMOS technology. This voltage is needed for powering a micromachined electrostatic actuator, and it must be generated from a 5V ...

A Large-Displacement Out-of-Plane SOI Actuator for Applications in Confocal Microscopy

Christopher Rulon Bowes-Lyon Ellis
Luke P. Lee
Roger T. Howe
2001

A silicon-on-insulator actuator has been designed for large DC deflections out of the plane of a wafer. The design employs deep reactive ion etching with a delay mask of two distinct silicon dioxide thicknesses to form silicon structures...

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...