Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 50: Semiconductor Substrates: Structure, Epitaxy, Growth and Adsorption
O 50.1: Poster
Tuesday, March 21, 2017, 18:30–20:30, P1A
Mask aligner for shadow mask evaporation of nanostructures — •Simon Mathioudakis, Priyamvada Bhaskar, Tim Olschewski, Marcus Liebmann, Marco Pratzer, and Markus Morgenstern — II. Inst. Phys. B and JARA-FIT, RWTH Aachen University, Germany
In order to arrive at an experiment for detecting Majorana fermions using scanning tunneling microscopy, we aim at evaporating superconductors with pierced holes onto a topological insulator ((Bix−1Sbx)2Te3). This structure is produced by evaporating the superconductor through a shadow mask. The goal is an in-situ process of creating an array of pierced holes and thus keep the interface free of resists or residues. Therefore, a mask aligner operating in ultrahigh vacuum (UHV) is developed. It uses three piezo-drives to align the mask relative to the sample. Three capacitive sensors are used to determine the sample-mask distance down to a precision of 100 nm each. This technique has been successfully tested and as a first proof, gold has been evaporated onto HOPG and Si substrates. AFM and SEM characterizations reveal an edge width below 100 nm, however also indicate assymetry in the deposited holes due to a drift during evaporation.