Three-dimensional additive electron beam lithography

Abstract

The procedure for three-dimensional lithography with electron-beam induced deposition is described. The technique can be applied in scanning electron microscopes and does not contaminate the instrument. Various precursor materials with vapor pressures of mtorr at room temperature are investigated with regard to their suitability for different applications. Deposited materials are characterized with respect to topography, morphology, electrical and optical properties by scanning electron microscopy, high resolution transmission electron microscopy, conductivity measurements, and energy dispersive x-ray analysis. The results show, that the properties of deposited nanocrystalline materials can be selected to be insulating or conducting using different currents and voltages for the deposition process. High resolution and high aspect ratio structures are grown with this technique and are applied in many fields. In optics 2-dimensional phonon crystals can be custom designed and produced as filters with a narrow bandgap. For atomic force and scanning tunneling microscopy very fine tips having a high aspect ratio are produced on top of conventional commercial probe tips, or on thermally heated etched tungsten tips, or on fresh cut wire tips. Nanostructurization of materials renders deposited nanocrystalline gold dots of 20 nm diameter and 10 nm distance. K(Omega) to G(Omega) -resistors of a few micrometer in length are components for micro- and nanoelectronics. Electrodes and field electron sources for electron optical microsystems are built under computer control. A micro-tube of 0.25 micrometer in length can be built for vacuum microelectronics.