Surface-science aspects of vacuum microelectronics

Vacuum microelectronics (VME) concerns the design and manufacture of vacuum devices and components built to sizes and tolerances similar to those found in solid state microelectronic devices. This technology is well suited for use in electron devices of commercial importance, particularly flat-panel displays. The flat-panel display industry is projected to have annual revenues measured in the tens of billions of dollars by the turn of the century. As opposed to conventional electron tubes that utilize cathodes based on thermionic emission, vacuum microelectronic devices principally utilize cold cathodes based on field-electron emission. The introduction of field-electron emission cathodes can yield unique device performance; however, attaining the level of reliability required for commercial applications requires addressing a host of challenging surface physics and chemistry problems. In this review we outline the surface-science-related issues of importance in VME. These issues cover a large realm of surface science ranging from adsorption/desorption phenomena, surface diffusion, surface passivation, and the deposition of overlayers to cathode bombardment, field-electron current density limits, emission noise, low-voltage phosphors, thin-film growth, and voltage breakdown. As the field of VME is relatively new, many of these surface aspects have not been thoroughly investigated and many more remain to be identified.