Henry I. Smith

Fabrication of large area nanostructured magnets by interferometric lithography

Patterned arrays of magnetic elements may be useful as media for high density magnetic storage applications. Interferometric lithography has been used to fabricate arrays of cobalt and nickel pillars with periods of 200 nm over areas of 5 cm/spl times/5 cm using a UV laser. This provides an economical and rapid method for manufacturing particle arrays.

Field emitter arrays for low voltage applications with sub 100 nm apertures and 200 nm period

Fabricated 70-nm-gate aperture silicon FEAs with turn-on voltages as low as 10 V. We demonstrated emission currents of 1 /spl mu/A at V/sub g/ of 13 V. Transmission electron microscopy (TEM) of the tips verified that the tip radii have a log-normal distribution with a mean radius of 4.5 nm. The measured tip radii are consistent with the electrical characterization of the devices.

Modelling of hysteresis loops of arrays of 100 nm period nanomagnets

Magnetic hysteresis loops have been measured for a 100 nm period array of 35 nm diameter nickel pyramids formed by interferometric lithography. Results are compared with a computational model which describes a square array of Stoner-Wohlfarth particles. This allows the distribution of particle anisotropies and easy axis directions, and the switching mechanism, to be inferred.

Nanostructured Origami (Trademark) 3D Fabrication and Self Assembly Process for Soldier Combat Systems

Abstract : The Nanostructured Origami(Trademark) 3D Fabrication and Assembly Process is a method of manufacturing 3D nanosystems using exclusively 2D lithography tools. The 3D structure is obtained by folding a nanopatterned 2D substrate. We report on the materials, actuation and modeling aspects of the manufacturing process, and present results from fabricated structures.

100 nm gate aperture field emitter arrays

We report the results of experimental and numerical simulation studies of the scaling of FEA gate apertures. Numerical simulation of realistic device structures was performed using a commercially available electrostatic simulator and custom written software. Our device simulations indicate that FEAs will operate with a gate to emitter voltage below 15 V if the gate aperture is scaled to 100 nm. At this operating voltage the FEA can provide an array current density of at least 10 /spl mu/A/cm/sup 2/ which should be adequate for use in a notebook computer type flat panel display.

Magnetization reversal in sub-micron nanoring arrays

In this paper, we report on the magnetization reversal exhibited by arrays of sub-micron ring-shaped nanomagnets (nanoings). The nanoring arrays were characterized by scanning electron microscopy and atomic force microscopy.

Evaporated electron beam sensitive organic resist for the back-patterning of X-ray lithography masks

One of the most important issue in the choice of a next generation lithography technology is the availability of adequate mask fabrication technology to demonstrate the extendibility of the technology to future technology nodes. In the case of X-ray lithography, it has been demonstrated that it is necessary to reduce the mask-to-wafer gap in order to achieve very high resolution. In order to do that, one solution is to pattern the absorber on the back of the membrane. This allows a reduction of the risks of accidental contact between the absorber patterns and the wafer during exposure and reduces turbulence in the gas flow in the mask-to-wafer gap. This paper presents characteristics of QSR-5, a negative organic sterol-based resist that is used to perform such patterning on the back of membrane. As it is impossible to spin-coat a resist on the back of a membrane substrate, one interesting characteristic of QSR-5 is that it is deposited by evaporation. This evaporation is performed using a joule-effect evaporator with an initial pressure of 3x10/sup -7/ torr. The temperature of the evaporation boat is kept below 200°C to maintain the integrity of the evaporated organic molecules. A LEO 1530 FEG-SEM with external control of the beam position is then used to pattern QSR-5, forming polymerized structures in the exposed regions. The resist is developed by immersion in a solvent solution.