Emission characteristics of silicon vacuum triodes with four different gate geometries

Arrays of 10*10, 30*30, and 50*50 phosphorus-doped 0.005-0.025 Omega -cm, monocrystalline silicon field emitters have been fabricated with an emitter height of approximately 4.5 mu m, a cone angle of 110 degrees , and four gate openings ranging from 1.8 to 5.3 mu m. The placement of the rims of the gates range from coplanar with the apexes of the emitters for the 1.8- mu m devices to fully recessed for the 5.3- mu m devices. The devices have been characterized in terms of geometry-dependent beta factors, scaling of emission currents with array size, temperature dependency from room temperature to 48 K, pressure dependency from 2.5*10/sup -9/ to 0.8*10/sup -5/ torr, current fluctuations at room temperature and at 48 K, and image formation. All of the measurements have been performed by operating the devices in the gate-induced field emission mode.<
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