MEMS-Based Sensors as Enablers of Advanced Scientific Research

The technological revolution occurring over the last thirty years in miniaturization is being recognized by a growing number of scientists as an untapped resource in nearly all technological fields. Examples I have worked on include: scientists studying global warming and geological CO2 sequestration desire precise gas sensor arrays to estimate spatially-distributed greenhouse gas exchanges; scientists mapping untapped oil and gas reserves are looking to a plurality of highly sensitive multi-axis accelerometers to be integrated into deployment systems on mile-long cables; population-based exposure assessment epidemiology studies to understand the links between particle exposure and human health can be vastly improved by modern, miniaturized particulate matter exposure assessment instrumentation. My work at Lawrence Berkeley National Laboratory was directed at identifying such needs and building working micro systems usable by scientists to perform their advanced research.

In this talk, I will present my work on five micro systems enabled by MEMS fabrication techniques. Specifically, I will discuss two acoustic sensors: 1) a new particulate matter sensor capable of speciation to study the links between particle exposure and human health, and 2) an ocean going dissolved organic carbon monitor for measuring the health of the ocean as a biological and carbon sequestration pump. I will also highlight three works which enhance transmission electron microscopy (TEM) studies: 1) a silicon-on-insulator microfabricated dark field annular aperture for Z-contrast, electron tomography and advance phase analysis, 2) an electrostatically actuated nano-cantilever for fracture and fatigue studies of dimensionally constrained materials, and 3) a shape memory alloy actuator enabling in-situ study of microstructure as a function of biaxial stress. I will also present a short synopsis of my Ph.D. thesis work illustrating the effect crystallization parameters have on microstructure and transformational behavior of super-elastic, shape memory alloy films. This work highlights the need for advanced characterization to ensure proper processing of materials for MEMS.