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In recent years vacuum microelectronics (VM) based on field emiuer array1 (FEA) concept has experienced tremendous growth. VM devices benefit from collision-free motion of electrons in vacuum, enabling faster modulation and higher electron energies than possible with solid-state structures. In addition TM devices can operate in a wide temperature range, 4K<T<1000K, and in high-radiation environment. Applications include FEA flat-panel displays, microwave amplifiers, digital IC, electron and ion guns, sensors, high energy accelerators, electron beam lithography, free electron lasers, and electron microscopes and microprobes. Innovative approaches to FEAs were made in latest years with respect to PEA materials, structure, and applications. A number of TM devices have by now moved beyond the research laboratories to actual prototypes and commercial products. Now silicon is considered as one of the most suitable material for FEA fabricating in batch technology (see e.gJ21). Silicon, though has orders of magnitude fewer conduction band electrons than metals, has emitting characteristics comparable to metals, and highly developed silicon batch technology can be applied to make various VM devices, including transistor-like structures. There are many specific aspects and special requirements for VM, and comprehension of physics of VM devices functioning play a key role in its successful development. One of the most important problem is the creation of FEA with sufficiently high, controlled, and stable emission ability. Field emission from semiconductors has some peculiar features which should be taken into account in silicon-based VM. High electric field penetrates deep enough into the semiconductor and results in intense electron heating near the emitting surface. Since the tunnelling coefficient exponentially depends on energy, this drastically effects the emission characteristics and heat dissipation. Thus the electron transport in semiconductor field emitter is in fact highly nonequilibrium hot electron process. It was well demonstrated in3'4 for one-dimensional model. However two-dimensional (2D) approach is principal for real cathodes modelling57. It is an actual physical and practical problem which is rather complicated and can be solved accurately enough by means of numerical methods only. In this paper we report on 2D numerical simulation offleld emission from silicon wedge microcathode structure.
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