In this review/tutorial paper, we cover the history, physics, and current status of vacuum microelectronic devices. First we overview the performance requirements of vacuum microelectronic devices necessary for them to replace, or fill voids left by, solid state devices. Next we discuss the physical characteristics of micro-field-emission sources important to device applications. These characteristics include fundamental features, such as current-voltage data and noise, in addition to engineering considerations, such as life expectancy and procedures for tube assembly. We conclude with a review of a wide variety of demonstrated and proposed devices based on vacuum microelectronic principles, including electron guns, microwave tubes, and flat-panel displays. >

Vacuum microelectronic devices

A thermal de-ice and anti-ice system for aircraft surfaces employs a laminate in which flexible expanded graphite foil is an electrical and heat conducting layer that is disposed below an outer heat conducting layer, with an electrically insulating layer below the graphite layer. The flexible expanded graphite layer requires about three times less wattage than known resistance heating pad thermal systems to achieve de-ice and/or anti-ice temperatures. The temperature of the surface is controlled by varying the power supplied to the flexible expanded graphite layer of the laminate in response to a real time temperature value transmitted to a power control.

De-ice and anti-ice system and method for aircraft surfaces

An electron beam generator particularly adapted for direct-write semiconductor lithography applications is disclosed which includes a photoemissive cathode, a modulable laser for illuminating the photoemissive cathode, and light optics to create an optical pattern on the cathode. The photoemissive cathode is composed of a light transmissive substrate onto which is deposited an optically semitransparent, electrically conductive film. This film in turn is coated with a thin layer of a photoemissive substance such as cesium antimonide so that the photoemissive cathode emits an intense and substantially monochromatic beam of electrons upon laser light illumination. The emitted electron beam is configured in accordance with the optical pattern created on the cathode, and in passing through successive electron optical devices is further shaped and sized for use, for example, in lithographically generating very large scale integrated (VLSI) circuits on semiconductors.

Laser stimulated high current density photoelectron generator and method of manufacture

An electrothermal zoned de-icing system for an aircraft employs a heat-conducting tape bonded to the leading edge of an aircraft structure. The heat-conducting tape has a spanwise parting strip area, and first and second ice accumulation and shedding zones. The tape comprises a non-metallic electrical and heat conducting layer consisting of flexible expanded graphite foil laminated to an outer heat-conducting layer, in which the thickness of the flexible expanded graphite foil layer in the parting strip area is always greater than the thickness of the foil layer in either of the ice accumulation and shedding zones. Therefore, the parting strip area has a decreased electrical resistance, a greater flow of current, and becomes hotter than the zones in which the foil layer is thinner. Because the flexible expanded graphite foil is a monolithic structure that may be shaped, sculptured or layered to form different thicknesses in different areas, only a single control mechanism for a single set of electric terminals is necessary to produce desired watt densities and temperatures in the parting strip and ice accumulation and shedding zones.

Aircraft de-icing system

A field-emitter switching device wherein a positive pulse is applied to a te (which is held at a bias potential V1 just below turn-on). A collector is held at a potential higher than the gate in order to collect emitted electrons from a field emitter source. As the voltage is applied to the gate, electrons are emitted immediately from the source and travel to the most positive potential at the collector. Because of the field emitter geometry, such electron transport is extremely fast. The ultra-fast switching speed is attained because the electrons reach near-maximum velocity within a few field tip diameters of the source.

Ultra-fast field emitter array vacuum integrated circuit switching device

An integrated circuit operative in vacuum and having all circuit elements formed in coplanar fashion on a single surface of a substrate to provide superior performance even in the presence of adverse environmental conditions. The circuit is especially adapted to microminiaturization and includes a unique electron discharge device having coplanar electrodes easily formed on a substrate surface by relatively simple film deposition techniques.

Donovan V Geppert

Papers

Integrated vacuum circuits

High efficiency cathode structure

Semiconductor-type photocathode for an infrared device