Leon Abelmann

Laser interferometric nanolithography using a new positive chemical amplified resist

The authors report on the progress of laser interference lithography at 266 nm laser wavelength with a chemical amplified resist containing a polyvinyl derivate dissolved in propylene glycol monoethyl ether ester. A continuous-wave deep-UV source combined with a Lloyd mirror is a simple and useful tool for the fabrication of nanoscale periodic structures generally called nanoarrays. Aiming for a robust pattern transfer technique to fabricate nanoarrays into magnetic materials, the authors investigated the utility of a chemical amplification positive tone resist, despite the relatively high theoretical resolution limit of 133 nm (λ2) pattern period for the laser source used. Taking advantage of this new type of resist, the authors demonstrated for the first time the fabrication of an 18 Gbit in.2 dot pattern on a platinum thin film.

On the vectorial calibration of a vibrating sample magnetometer for thin film measurements

A calibration method for the biaxial vector Vibrating Sample Magnetometer (VSM) is proposed to reduce the so-called `cross talk’ error, often observed during angular measurements on magnetic thin films. The coil system of the biaxial vector VSM consists of two sets of coils, one for each of the two co-ordinate axes. The method takes into account that each coil set is sensitive to all components of the magnetisation vector and moreover that the sensitivity to the components parallel and perpendicular to the film plane can be different. A correction for demagnetisation should be used to compensate the fact that the sample used for the calibration cannot be fully saturated with an applied field at angles close to the normal of the film plane. Curve-fitting on the sensitivity curves is used to reduce noise. These procedures result in a calibration which reduces the cross talk by a factor 4–8 depending on the coil configuration and the size and shape of the samples used.

Micro-assembly of three dimensional tetrahedra by capillary forces

This paper presents the realization of micrometer sized silicon nitride tetrahedra with well-defined angles that are folded out of a planar geometry using capillary forces. The required specific three-dimensional shape is achieved by a well-defined folding sequence. Using the favorable properties of the recently developed corner lithography technique, a programmable stop hinge is micro-machined by etching specifically defined intersection planes of the silicon mold. Tetrahedra were successfully folded by capillarity validating this new technique. The demand for such a microstructure has become very large since it can form the essential basic element for future three-dimensional data storage systems.