Triode Field Emitter Array Design And Production

Vacuum micro-electronics devices, which are based on field emission theory, are more and more widely applied, because of their low power consumption, high current density and high frequency. The performance of field emission device is mainly depending on field emitting cathode. In recent years with the progress of research, the structure of field emitter array, cathode materials, and fabrication process are dramatically improved.Among various types of triode emitter arrays, the molybdenum emitters made by Spindt in SRI lab and silicon emitters made by oxide-sharpening process are the most widely used, both of them were easy to be fabricated on silicon substrate, because of its simple process and compatibility with VLSI technology.The field emitter arrays with submicron gate apertures for low voltage operation have been successfully fabricated by modifying the conventional Spindt process. The key element of the new process is forming the gate insulator by local oxidation of silicon, resulting in the reduction of the gate hole size due to the lateral encroachment of oxide. Then aluminum was deposited at a grazing angle to form a parting layer using the thermal evaporator. Molybdenum was deposited subsequently by the same machine, resulting in the formation of an emitter cone on the cathode. The overlying structure was lifted off by removing the parting layer selectively. Molybdenum field emitter triode array was successfully fabricated.Research in my paper is mainly concentrated on etching process of cavity and fabrication of the molybdenum tips. Molybdenum was Deposited on samples with different etching parameter, Cross-sectional view was observed by SEM. Gate aperture, tip height, and tip curve radius were also measured. Finally emitter array which has tip radius less than 20nm was obtained. Then influence of all parameters was also stimulated by software.Lanthanum hexaboride film was successfully deposited on molybdenum emitter array for improving its emission characteristic. Test equipment was designed for emission characteristic measurement of molybdenum emitter and composite emitter . experimental result are discussed and some improving methods are given.