Field Emission Cathode Small Gate Hole Array Developed

The term vacuum microelectronics is used to describe devices or components of micron-sized dimensions.This is in contrast to solid state microelectronics,which refers to similar sized devices of a semiconductor. It has the unique advantage of a vacuum device, of course, the device can achieve integration. Compared with the solid state microelectronics devices, vacuum microelectronics devices has its unique advantages: higher-speed electronic transmission; ability to work in adverse environment; lower power loss; small size and light weight because of IC technology; potential of large-scale production. Recently, vacuum electronics technology is a hot research field all over the world. Applications of vacuum electronics technology include field emission displays, high frenquence and power microwave devices, switching devices and future high-density memories etc.At prescent, most vacuum microelectronics research are mainly concentrating on the preparation, properties and applications of the field emission cold cathode. Now silicon and molybdenum are the most popular materials used for tip field emitter arrays.However, the Mo tip cathode is also called Spindt cathode, its fabrication was based on thin film methods and angle evaporation technology. For practical applications,it is desirable for the emitter array to have as low an operating voltage as possible. Scaled-down field emitters are expected to operate at low voltages because of their small dimensions and to provide high current density because of their high packing density. Therefore it is an important issue in the fabrication of Spindt-type field emitter arrays how small the size of the apertures on the gate electrode can be consistently patterned. Small gate aperture can lower the control voltage, also can reduce the divergence of the electron beam.In connection with this issue, it has been reported that ion beam and electron beam lithography, which have some disadvantages such as narrow field size, high cost, and low throughput, can be used to fabricate FEAs with submicron gate apertures. Some researchers have introduced the interferometric lithography, but it is less mature to be used in the manufacture of FEAs.In this paper, we present a new process scheme as an alternative approach to fabricate FEAs with submicron gate apertures for low voltage operation.This scheme has a special feature that the submicron-sized gate apertures can be easily fabricated by means of local oxidation of silicon (LOCOS), even with a conventional contact printer. After achieve the gate aperture, we can fabricate field emission tips with evaporation technology which be used in fabricating Spindt cathode, and the material used here is Mo or other better materials. Simulation of the field emission cathode which has small gate aperture shows that the smaller gate aperture, the lower control voltage; the smaller gate aperture, the less divergent of the electron beam.