Date of Award
Doctor of Philosophy
Materials Science and Engineering
Philip D. Rack
Kurt E. Sickafus, Eric D. Lukosi, Gerd Duscher, Jason D. Fowlkes
A focused electron beam deposition process (FEBID) coupled with in-situ infrared pulsed laser assist (LA-EBID) has been implemented for higher purity tungsten nanowires using W(CO)6 [tungsten hexacarbonyl] as parent precursor gas. Nanowires made of Co from Co2(CO)8 [dicobalt octacarbonyl] and Pt from MeCpPtIVMe3 [trimethyl methylcyclopentadienyl platinum] have also been realized by using inert focused ion beams of helium and helium and neon, respectively. In all cases, higher electrical conductivities, higher purities and larger grain sizes have been obtained when compared with preceding traditional additive edit techniques. These new approaches will make possible successful nanoscale direct-write processes on complex structures of high technological relevance such as the Mo/Si EUV reflector mirror.
Etching of a nickel top absorber layer has been attained by using a neon focused ion beam (Ne-FIB), but not with a He-FIB. Subsurface or collateral damage due to defect generation and interactions still remains a side effect that needs to be minimized and corrected. Experiments made in a helium ion microscope (HIM) indicate that endpoint detection is possible for monitoring when a top film (Ni, Au, Cu, and SiO2 [silicon dioxide]) in a multilayer structure has been milled through to an internal boundary by using a neon focused ion beam. In the case of helium ion irradiation, the electronic signature corresponding to the onset of nanobubbling (or swelling) has been captured, hence improving the detectability of this adverse effect. Models using an empirical 2-D Lambertian distribution have been deployed to predict how the secondary electron (SE) emissions vary as a function of the etch geometry and composition for one-, two- and three-component systems.
Gonzalez, Carlos M., "Elucidating Fundamental Mechanisms in Focused Electron- and Ion-Beam Induced Synthesis. " PhD diss., University of Tennessee, 2014.