Vacuum microsystems for energy conversion and other applications

Silicon gyroscopes and resonators have motivated rapid progress in techniques for wafer-level, high-quality vacuum encapsulation. This paper reviews recent developments in this technology and describes how it provides a foundation for new microsystem applications that involve electron transport across vacuum gaps. Thermionic energy converters, as well as the recently reported photon-enhanced thermionic energy converter, involve vacuum encapsulation of microcathode arrays. These devices pose a variety of material and process challenges, due to their high operating temperatures. A second promising application is aimed at efficient generation and processing of signals in the THz region, by means of resonant-cavity vacuum oscillators.