RF Vacuum Microelectronics

We summarize our third quarter progress and discuss fourth quarter plans for the development of an edge emitter based vacuum triode with performance goals of 10 microAmp/micrometer emission current density at less than 250V and which can be modulated at 1 GHz for 1 hour. Fabrication of four process runs of field emitter diodes were completed. Initial testing indicates promising results. current densities of 5 MicroAmp/micrometer were measured on selected devices. Continuous emission for 70 hours was measured on devices with emission currents in the 5 microAmp range. Maximum currents of 155 microAmp for 100 long devices were also measured; these emission currents are a factor of ten higher than previously measured from an edge device. Design of triode emitter mask set was completed this quarter and a mask set was ordered. Thermal finite- element-analysis (FEM) of the triode structure indicates that ionic heating from the anode is the principal mechanism for large temperature rises at the emitter edge.