Integrated field emission micro source for electron optical applications

For some optical application, electron sources require additional gates besides one extraction gate to focus or accelerate the emitted electrons coming through the extraction gate from the field emission tip. To realize multiple-gated electron source mentioned above, manual assembly of the tip and gates has been a usual idea, but it has some limitations; poor cylindrical symmetry and low productivity due to manual alignment and assembly. In this work, self-aligned integrated field emission micro source with multiple gates was fabricated using VLSI technology and silicon bulk micromachining technology. The field emission tip was formed by PECVD oxide deposition on top of hole-trench. The hole-trench was patterned by electron beam lithography and RIE. To make a path for the emitted electrons, silicon bulk micromachining was performed and highly boron doped layer was used as an etch-stop layer of silicon bulk etch in EDP solution