Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 49: Poster: Nanostructures on Surfaces I

O 49.29: Poster

Tuesday, March 13, 2018, 18:15–20:30, Poster A

Ultrahigh vacuum piezo-based mask aligner for shadow mask evaporation with sub-100 nm precision — •Priyamvada Bhaskar, Simon Mathioudakis, Tim Olschewski, Florian Muckel, Jan Rafael Bindel, Marcus Liebmann, and Markus Morgenstern — II. Institute of Physics B, RWTH Aachen University, 52056 Aachen, Germany

Realizing nanostructures in ultrahigh vacuum (UHV) could be beneficial for many experiments including the STM investigation of lateral interfaces or quantum transport experiments employing a 4-tip STM. Another example is to realize a clean interface for the detection of Majorana fermions, where in-situ evaporation of superconductors with pierced holes onto a topological insulator ((Bi_x−1Sb_x)₂Te₃) is a controllable setup. Using three piezo-drivers on the mask aligner and three capacitive sensors on the shadow mask, the sample-mask distance can be controlled with a sub-100 nm precision and the mask can be aligned parallel to the sample surface. Mask and sample can be exchanged in-situ and the sample can be moved laterally with respect to mask using an additional piezo motor. The precise control of the mask-sample distance allows to minimize the penumbra of evaporated regions and improves the quality of the lateral interface. We demonstrate µm-sized patterns of Au on Si(100) with penumbra as low as 90 nm and show that the penumbra increases with increasing mask-sample distance.