Physical considerations in vacuum microelectronics devices

The author addresses the physical considerations that must be taken into account when the dimensions of a triode vacuum tube are reduced to micrometer and submicrometer levels, which are commonly used in solid-state microelectronics devices. For very high-speed devices, it is shown that vacuum transit times between comparable electrode spacings (0.5 mu m) can be smaller by a factor of between 1.5 and 15 compared to those for the best solid-state materials. Vacuum devices are also less sensitive to radiation damage and can operate at higher temperatures than solid-state devices.