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Willy Lim- ​ESR 14,  September 2018 - August 2021

RAITH, Germany

Master thesis: "Setup of a magneto-optical microscope and characterization of skyrmionic bubbles"

The main task was setting up a new magneto-optical Kerr microscope coupled with electrical transport measurements for the Spintec laboratory. The main purpose was to have a dedicated equipment for the study of skyrmions. I put together the differents parts of the whole setup, installed the softwares. I also designed pieces on SolidWorks, created a LabVIEW module to control the contacting tips. Afterwards, I did magneto-optical Kerr effect (MOKE) measurement on this microscope and also another MOKE setup. Measurements were done on wafer with double wedges (magnetic material and oxide) with different materials. Supervisor: Hélène BEA, SPINTEC, CEA-Grenoble, France

Personal Training Committee

Main supervisor: Guido Piaszenski, RAITH

Co-supervisor: Elke Scheer, UKON

Mentor: Felix Casanova, NanoGUNE

Planned secondments

At NanoGUNE (January/February 2019): Quantum devices nanofabrication,

At AALTO (May 2019): Electron transport measurement,

At UKON (January, March and August 2021): Transport measurements at very low temperature.

PhD Project

Developing novel Electron Beam Lithography (EBL) methods and recipes

Objectives: I will further develop existing EBID recipes as method for the local deposition of insulators (SiOx) and metals with spatial resolution in the 20 nm range. The deposited material may serve as electrical insulator for complex nanoelectrical circuits, as etch masks for further RIE processes, or as conducting part of the circuit. With EBID, more versatile circuit designs are possible than with standard shadow-evaporation techniques.

EBID will be developed on planar and non-planar substrates (e.g. after a first lithography step). I will explore whether the local deposition of metal (Au, Pt, W) is possible to bridge between nanoelectrodes and to form a QD. I will optimize the success of the process development by in situ electrical characterisation and height detection as well as by ex situ TEM to detect the element composition of the deposited material. The post processing and electrical characterisation of the devices will be performed at UKON. In addition, I will further improve EBL by exploring the minimum feature size using advanced resists and multi-angle evaporation in combination with improved imaging techniques using a specialised electron detector. These process improvements will be beneficial for the projects of ESR 4, 9, 11 and 12 and will be developed in collaboration with them. This includes the fabrication of EBL samples for the above-mentioned ESRs.