Introduction

Focused ion beams (FIB) are promising tools in micro- and nanotechnology as well as in material analytics. Characteristic properties are the Nanometer spot size, the energy range from some eV up to 200 keV, the high current density and a broad spectrum of ion species. In commercial FIB systems Ga liquid metal ion sources (LMIS) are usually employed, but in some rare cases also liquid metal alloy ion sources (LMAIS) are used. FIB systems allow to create structures of arbitrary shape with dimensions on the nm scale.

Production

The ion fine beam laboratory in the institute has equipment and extensive experience for the development and production of liquid metal hairpin-type ion sources for different source materials like :

Au₇₃Ge₂₇, Au₈₂Si₁₈, Ce₈₀C₂₀, Co₃₆Nd₆₄, Er₆₉Ni₃₁, Sn₇₄Pb₂₆, In₁₄Ga₈₆, Ga₃₈Bi₆₂, Ga₃₅Bi₆₀Li₅ as well as new sources on demand ...

Test und characterization

The following parameters are determined for the test and characterisation of the sources:

• current-voltage characteristics, emission stability, lifetime and emitter-temperature behaviour, long-term stability.
• Mass spectra
• Angular distribution and angular intensity by means of a rotating Faraday cylinder
• Ion energy distribution as well as energy shift of each emitted component of the source through a mass filter and a retarding field energy analyzer

Instrumentation

• TIBUSSII - Orsay Physics NanoSpace system equiped with a 5 nm SEM, a 7 nm mass-separated Liquid Metal Alloy Ion Source FIB and a 17 nm mass-separated Plasma FIB
• 2x Orsay Physics CANION Z31Mplus mass-separated FIBs (semi-kommerziell), which can provide various ion species using in-house developed ion sources, for dedicated research Topics
• Carl Zeiss NVision 40 CrossBeam Ga-FIB for standard applications like ion beam lithography or TEM lamella preparation
• Carl Zeiss ORION NanoFab, 2x Carl Zeiss ORION Plus Helium Ion Microscope He/Ne-FIB
• Hitachi Ion Milling System ArBlade 5000 for sample crosssectioning, 500µA of 10 keV Ar, sputtering of > 1 mm / h
• Leica EM TXP Target Surfacing System for target preparation like milling, sawing, grinding, and polishing of samples with an integrated stereomicroscope

Current projects

Enabling New Quantum Frontiers with Spin Acoustics in Silicon EQUSPACE (02/2025 – 01/2029), gefördert durch HORIZON-EIC-2024-PATHFINDEROPEN-01-01 (Project Number 101185817), press release.

Although silicon has been the defining material of classical information processing, it is currently not the main material advanced for quantum information processing. It would however be very compelling to leverage the existing multibillion euro silicon infrastructure. Silicon spin qubits have already been shown to have excellent single-qubit properties, combining long coherence times with high-fidelity readout and control. The reason silicon qubits are not yet seen as a mainstream platform for quantum computing is mainly due to the lack of convenient coupling and readout mechanisms that could be used to scale-up to practical level. This proposal addresses both deficiencies and aims to enable a longterm future for donor spin qubits in silicon in Europe, for both quantum processing and quantum sensing applications.

This project will provide a scalable solution for all the important aspects of a quantum platform: control and readout, spin-spin coupling, and routing quantum information on-chip. In parallel, we will advance the needed material science methods, concentrating especially on deterministic single-ion doping, isotopical purification and strain tuning of silicon.

The end product of the project will be a complete quantum information platform including qubits, interconnects and scalable control and readout electronics. The platform will be based on embedded atomic spins as qubits, phonons as interconnects and gate defined quantum dots with on-chip multiplexing and amplification as readout devices. The project will bring together the relevant parties in Europe into a collaboration that will form a new hub for donor spinbased silicon quantum computing. The created network will span focused ion beam based single-ion implantation and isotopic purification facilities, semi-commercial silicon foundries, start-up companies working on silicon quantum dots and research groups researching silicon spin quantum computing and quantum acoustics.

Development of an emitter maker for the production of liquid metal ion sources from refractory components EMIE (03/2024 - 02/2026), funded by AiF/BMWK (32 46231 003)

In the fields of quantum technology and magnetic nanostructures, there is increasing demand for the utilisation of further refractory and air-reactive chemical elements in focused ion beam (FIB) systems. The ion beams are generated from alloys in liquid metal alloy ion sources (LMAIS), the components of which have melting points well above 1000°C and some of which are highly reactive in air. This resulted in unsafe operation of the sources. Raith GmbH is a globally active company in the field of nanostructuring. The Ion-Induced Nanostructures working group at the HZDR is involved in the production and characterisation of new types of LMAIS and the development of new types of spectrometers. The aim of this project is to develop a production technology that enables a variety of air-reactive elements with high melting temperatures. The chemical purity of the sources as well as various manufacturing and operating parameters must be monitored and standardised for quality management. The aim of the project is the reproducible, contamination-free production and function of a new range of LMAIS.

Gallium Oxide Fabrication with Ion Beams GoFIB (05/2022 – 05/2025)

GoFIB (Reference Number: project9659), press release

Gallium oxide is a novel ultra-wide band gap material, and the rationale is that its thin film fabrication technology is immature. In particular, the metastability conditions are difficult to control during sequential deposition of different polymorphs with existing techniques. However, the polymorphism may turn into a significant advantage if one can gain control over the polymorph multilayer and nanostructure design. Our objective is to develop a method for the controllable solid state polymorph conversion of gallium oxide assisted by ion irradiation, capitalizing on encouraging preliminary data. This fabrication method may pave the way for several potential applications (e.g. in power electronics, optoelectronics, thermoelectricity, batteries) and we will test the corresponding functionalities during the project. Thus, we envisage multiple positive impacts and potential benefits across a wide range of stakeholders.

Former Projects

All publications

Recent publications

2025

2024

2023