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Heavy ion lithography using self-assembled colloidal particles as a mask enables micro- and nano-patterning of surfaces. The resulting patterns can be tuned by varying the mask configuration, i.e. packing geometry of the colloidal particles and number of particle layers. In this work we present several patterns, which can be transferred to rutile TiO2 single crystals by irradiating through self-assembled layers of silica micro-spheres with 25 MeV Br ions. As the induced ion tracks in TiO2 have a very high etching selectivity the patterns can be developed in HF with very high contrast. This makes it possible to prepare large patterned areas which can be of interest for e.g. optical applications.

A method for producing ordered carbon nanopillar arrays is presented. The method is based on ion irradiation through a small anodic porous alumina membrane, resulting in carbon deposition within the centers of the pores on a gold covered SiO2/Si substrate. Samples were irradiated by 4 MeV Cl2+ ions with fluences of . The combined use of pick’n place positioning of the small porous alumina templates and ion beam irradiation is well suited for post-processing on silicon based integrated circuits. It provides fast local deposition at low temperature of high-density ordered carbon nanopillar arrays in larger silicon based systems, e.g., for field emitting or biosensors applications.

Ordered nanoporous alumina samples with a pore diameter of 70 nm, an array period of 100 nm and several thicknesses were considered as possible masks for pattern transfer by MeV ion lithography. A simple procedure for the sample alignment using a 2 MeV He+ beam was utilized. The energy distributions of transmitted ions as well as backscattering spectra were studied in aligned and non-aligned orientations. The best transmission, comparable to the relative surface area covered by pores, was reached for 2 mum thick samples and was independent on ion species. Although the transmission for thicker membranes was generally lower, it significantly depended on the quality of each individual sample. The presented ion beam technique can therefore be used as a tool for the characterization of porous materials. The acceptance angle for transmission through pores and the effective atomic density of samples can be obtained from the experimental data and it is shown that nanoporous alumina can be used as a mask for MeV ion lithography., QC 20100525 QC 20110926

For a practical ion-lithography column of 150 kV, the light elements Li, Be, B, C, and Si were found to be the most promising for resist exposure. With the exception of Li, these elements emit doubly charged ions when used on a liquid metal (LM) ion source. Lithium, although highly reactive, can be operated as a single-element species, while the others must be used in alloys. Mass spectra for alloys of Be-Au, Si-Au, and B-Pt were obtained and showed significant fractions of the desired ion species. A new LM ion source structure (needle and heater assembly) was tested and found to improve the stability of the Be-Au ion emission. This ion source structure appears to be suitable for all elements and alloys considered for resist exposure. The results show that 0.5 micrometers of resist can be exposed with Be+ ions at an energy of 60 to 80 keV while the same exposed depth requires 175 to 200 keV for Si+ ions. Focused-beam exposures in PMMA were made using the Be40-Au60 alloy as the ion source material. Since the focused beam was not mass separated, the gold was implanted along with the beryllium. Because of the short range of the gold ions, polymerization of the resist occurred at doses greater than approx. 9 x 10 to the 12th power Be(++)/sq cm. The low Be(++) dose at 55 kV is not sufficient for maximum range, and most of the exposed depth is due to the combination of Be+ and Be(++) ions.