Silicon field emitter array design for 10 GHz modulation

Summary form only given, as follows. Silicon field emitter arrays show exciting potential applications as cathodes for microwave power devices. This presentation will discuss design considerations, fabrication techniques, test methods and results for silicon field emitter arrays produced at MCNC. Field emission, or cold cathode technology has advantages over thermionic cathodes for use in microwave power devices. These include: electron generation without the need for a cathode heater and its power supply, electrical modulation of the electron beam at the source to produce pre-bunched groups of electrons, and the ability to sustain current densities higher than predicted by the Langmuir-Child law. Advantages silicon field emitter arrays have over cold cathodes produced using other technologies include the use of well-established fabrication techniques from the semiconductor industry and the ability to place the emitter tips on tall columns. Additionally, large numbers of cathodes can be fabricated in a variety of shapes within a single fabrication run. To benefit from these advantages, careful consideration must be given to the device geometry and the materials used in the fabrication of the arrays to avoid excessive losses at high frequencies. Furthermore, the test equipment must be configured to manage power deposition in the anode, or measured performance will be limited. Early results at MCNC have shown that anode current modulation at 1 GHz can be produced and measured from a field emitter array. With continued advances in the technology, modulation at 10 GHz appears to be a reasonable goal.