Publications

Abstract not provided.

Novel technologies often are born prior to identifying application arenas that can provide the financial support for their development and maturation. After creating new technologies, innovators rush to identify some previously difficult-to-meet product or process challenge. In this regard, microsystems technology is following a path that many other electronic technologies have previously faced. From this perspective, the development of a robust technology follows a three-stage approach. First there is the ''That idea will never work.'' stage, which is hurdled only by proving the concept. Next is the ''Why use such a novel (unproven) technology instead of a conventional one?'' stage. This stage is overcome when a particular important device cannot be made economically--or at all--through the existing technological base. This initial incorporation forces at least limited use of the new technology, which in turn provides the revenues and the user base to mature and sustain the technology. Finally there is the ''Sure that technology (e.g., microsystems) is good for that product (e.g., accelerometers and pressure sensors), but the problems are too severe for any other application'' stage which is only overcome with the across-the-board application of the new technology. With an established user base, champions for the technology become willing to apply the new technology as a potential solution to other problems. This results in the widespread diffusion of the previously shunned technology, making the formerly disruptive technology the new standard. Like many technologies in the microelectronics industry, the microsystems community is now traversing this well-worn path. This paper examines the evolution of microsystems technology from the perspective of Sandia National Laboratories' development of a sacrificial surface micromachining technology and the associated infrastructure.

Two major problems associated with Si-based MEMS (MicroElectroMechanical Systems) devices are stiction and wear. Surface modifications are needed to reduce both adhesion and friction in micromechanical structures to solve these problems. In this paper, the authors present a CVD (Chemical Vapor Deposition) process that selectively coats MEMS devices with tungsten and significantly enhances device durability. Tungsten CVD is used in the integrated-circuit industry, which makes this approach manufacturable. This selective deposition process results in a very conformal coating and can potentially address both stiction and wear problems confronting MEMS processing. The selective deposition of tungsten is accomplished through the silicon reduction of WF{sub 6}. The self-limiting nature of the process ensures consistent process control. The tungsten is deposited after the removal of the sacrificial oxides to minimize stress and process integration problems. The tungsten coating adheres well and is hard and conducting, which enhances performance for numerous devices. Furthermore, since the deposited tungsten infiltrates under adhered silicon parts and the volume of W deposited is less than the amount of Si consumed, it appears to be possible to release adhered parts that are contacted over small areas such as dimples. The wear resistance of tungsten coated parts has been shown to be significantly improved by microengine test structures.

This paper examines the impact of inserting Micro-Electro-Mechanical Systems (MEMS) into US defense applications. As specific examples, the impacts of micro Inertial Measurement Units (IMUs), radio frequency MEMS (RF MEMS), and Micro-Opto-Electro-Mechanical Systems (MOEMS) to provide integrated intelligence, communication, and control to the defense infrastructure with increased affordability, functionality, and performance are highlighted.