Roya Maboudian (Advisor)

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...

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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Sensing in harsh environment, especially high temperature environment, is drawing more attention, with potential applications in energy sector. The motivations are that enhanced (pressure, temperature, chemical) sensing will allow more efficient operation, enabling condition- based monitoring and reducing unwanted emission. State-of-the-art sensing technology remains limited, either not capable of long-term online monitoring under high temperature due to materials failure or, occupying too much space. We propose to adapt MEMS fabrication process and concepts to our proposed research...

We are designing a conductometric soot sensor that measures the change in conductance resulting from soot deposition onto the sensor. Although previous work has been done on conductometric soot sensing, current sensors are power intensive (5-30 W) and slow (60-170 s between sensing cycles) due to their large size, ineffective thermal insulation, and the high currents required for soot combustion (when self-regenerating). We propose to use MEMS fabrication methods to develop a miniaturized conductometric soot sensor with a built-in polysilicon microheater for self-regeneration, whose...