Characterization, surface treatment and nanofabrication by charged particle beams

Surface characterization and modification methods are an essential part of modern micro- and nanofabrication. Over the course of nine decades, electron microscopy has emerged as the main analysis method for a wide variety of materials. Developed in parallel with machines utilizing beams of electrons, focused ion beam systems have made their way from early analysis tools to include options for sophisticated fabrication of miniaturized devices. With a combined method of implementing electron and ion beams into the same machine, the number of analysis options has increased. In this thesis, three charged particle-beam methods are introduced that play a pivotal role throughout the work. While electron microscopy, electron tomography and focused ion beam are all established methods, in this work they are applied in materials analysis. In addition, in this work a focused ion beam is used as the main fabrication method in realizing both microdevices and thin-film device platforms. Several other standard fabrication techniques are applied in various processes throughout the work in realizing the presented applications. Focused ion-beam milling is applied to produce a device platform for low temperature physics applications. Focused ion-beam method also allows a rapid nanofabrication of silicon structures by gallium mask doping of silicon. Functional devices are fabricated by a combination of focused ion-beam doping and dry etching. This hybrid fabrication method enables high aspect ratio micro- and nanostructures. Charged particle beam based material characterization methods are applied to compound Nafion thin films for electroanalytical filtering applications. A standard negative staining method using uranyl formate was applied to Nafion thin films and is shown to improve both contrast and resolution in electron tomography. A new sample preparation method is developed and deployed together with new imaging modes enabling imaging of beam-sensitive Nafion in high resolution. A finger prick blood test strip based on the filtering properties of Nafion and carbon nanotubes is developed. The electrodeposition of copper on carbon nanotube fiber bundles is shown to be capable of increasing the electrical conductance of the bundle, and the copper growth mechanism of bundles is explained. Also it is shown that the corrosion protection of chromium nitride on steel is increased by closing the surface pinholes with an atomic-layer-deposited nanolaminates. Moreover a fabrication method of dual-type nanowires on a single substrate is introduced. Dual-type nanowires are fabricated in a novel method, that enables the fine tuning of the chemistry and optical properties of the nanowires for optical sensor applications.