Construction of a three-dimensional microtriode by nanolithography with electron-beam induced deposition

Electron-beam induced deposition is employed to build three-dimensional nanostructures like supertips for electron field emitters and microtubes. This is a novel technique rendering supertips with 15 nm tip radius and 50 nm length with 7.2 degree emission angle. This is a 25 fold increase in brightness if compared to conventional tungsten field emitters. Miniaturised microtubes are constructed under computer control with a cathode to anode separation of less than 700 nm and a cathode-grid capacitor in the fF range. Tubes with 5 parallel cathodes can have an estimated transconductance of 50 μSiemens and can be switched with 30000 electrons at 5 V in the 100 GHz range