Atom lithography of iron

Atom lithography is a technique in which a light field is used to pattern an atomic beam. This patterned flux is then deposited onto a substrate, resulting in a nanostructured thin film. The smallest structures that have been made thus far using this technique are around 30 nm wide. This thesis investigates the technique, expanding its possibilities. The work-horse for the development of atom lithography has been Cr, as this transition metal atom has a closed transition in a wavelength range that is accessible to dye lasers. We extend the technique to Fe, the first ferromagnetic element to be used for atom lithography. The setup that was used to do this experiment is described, along with its critical design parameters. We present nanostructures that are typically 50 nm wide, and up to 4 nm high. The spacing between the nanolines is 186.05 nm. The nanostructure profile is compared to that of a simulated deposition process, and found to match. To the authors’ knowledge, this is the first demonstration of direct write atom lithography without laser cooling. A preliminary incursion into the magnetic properties of the nanostructures deposited is presented. In addition to giving an overview of the general ferromagnetic properties that might be expected, a deeper investigation of the magnetic anisotropy of the nanostructures deposited in this experiment is given. Novel resonant light masks are used in an experiment performed at the University of Konstanz (Germany). These light masks, using exactly instead of nearly resonant light, reveal some intriguing quantum mechanical effects. The most important of these features is the possibility to place structures closer together – at quarter wavelength spacings rather than half-wavelength intervals. Finally, the influence of surface diffusion on the structures obtained in an atom lithography experiment is investigated using kinetic Monte Carlo simulations. Several diffusion limiting effects are investigated; the influence of small amounts of residual reactive background gas is found to describe the experimental observations

Atom lithography of Fe

Direct write atom lithography is a technique in which nearly resonant light is used to pattern an atom beam. Nanostructures are formed when the patterned beam falls onto a substrate. We have applied this lithography scheme to a ferromagnetic element, using a 372 nm laser light standing wave to pattern a beam of iron atoms. In this proof-of-principle experiment, we have deposited a grid of 50-nm-wide lines 186 nm apart. These ultraregular, large-scale, ferromagnetic wire arrays may generate exciting new developments in the fields of spintronics and nanomagnetics. (C) 2004 American Institute of Physics

Electrostatic clamp manufactured by novel method

Electrostatic clamps (ESCs), used in reticle and wafer handling, are presently manufactured using glass bonding and polishing technologies. We present a patented alternative concept to this process, relying on coating and etching processes rather than bonding. We manufactured a first prototype clamp based on a silicon-on-insulator wafer. The clamping operation was demonstrated, and the clamp’s performance was characterized. Clamping force, coating quality, and achieved morphology are characterized and understood

EBL2, a flexible, controlled EUV exposure and surface analysis facility

TNO is building EBL2 as a publicly accessible test facility for EUV lithography related development of photomasks, pellicles, optics, and other components. EBL2 will consist of a Beam Line, an XPS system, and sample handling infrastructure. EBL2 will accept a wide range of sample sizes, including EUV masks with or without pellicles. All types of samples will be loaded using a standard dual pod interface. EUV masks returned from EBL2 will retain their NXE compatibility. The Beam Line provides high intensity EUV irradiation from a Sn-fueled EUV source. EUV intensity, pupil, spectrum, and repetition rate are all adjustable. In-situ measurements by ellipsometry will enable real time monitoring of the sample condition. The XPS will be capable of analyzing the full surface area of EUV masks and pellicles, as well as performing angle resolved analysis on smaller samples. Sample transfer between the XPS and the Beam Line will be possible without breaking vacuum

Quantum features in atomic nanofabrication using exactly resonant standing waves

We report on the first fabrication of nanostructures with exactly resonant light revealing the quantum character of the atom-light interaction. Classically the formation of nanostructures is not expected; thus, the observed formation of complex periodic line patterns can be explained only by treating atom-light interaction and propagation of the atoms quantum mechanically. Our numerical quantum calculations are in quantitative agreement with this experimental finding. Moreover, the theory predicts that for small detunings nanostructures with ¿/4 period can be produced, which beats the standard nanofabrication limit of ¿/2. Our experiments confirm this prediction

Laser frequency stabilization using an Fe-Ar hollow cathode discharge cell

Polarization spectroscopy of an Fe-Ar hollow cathode discharge cell was used to lock a frequency-doubled Ti:sapphire laser to the 372-nm5D45F5 transition of 56Fe. The discharge cell produced a density of 1018 m-3 ground-state 56Fe atoms at a temperature of 650 K, this density being comparable to a conventional oven at 1500 K. Saturated absorption spectroscopy and two schemes of polarization spectroscopy were compared with respect to signal-to-background ratio and the effect of velocity-changing collisions. The laser was locked within 0.2 MHz for hours by feedback of the dispersive polarization spectroscopy signal