Helium Ion Microscopy

Helium Ion Microscopy (HIM) is an advanced focus ion beam technology that allows imaging and nano fabrication of conductive as well as insulating materials with unprecendented resolution.

Basics

HIM utilizes a the apex of a tungsten tip to ionize noble gas atoms. Shaping the tip on the atomic level allows to use only the last three atoms of the apex for this purpose. This trimer and apertures in the ion optical column lead to a source size of only 0.25 nm which results in a beam spot with a diameter of only 0.5 nm. Currently the gas can either be He or Ne. While the former is mostly used for imaging the later allows high resolution nano fabrication.

Instrumentation

• 0.5 nm He beam 10-35 keV
• 2 nm Ne beam 5-25 keV
• GIS injection system for IBID (W(Co)₆, HRD, XeF₂)
• In-situ backscatter spectrometry and secondary ion mass spectrometry (50 nm lateral resolution)
• 4 Kleindiek MM3A micromanipulators
• Heating stage (<500°C)

Orion NanoFab	HIM Trimer
Foto: Carl Zeiss	Foto: Gregor Hlawacek
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Applications

high resolution imaging	nanofabrication
semiconductors materials science polymers (uncoated) biological samples (uncoated) materials for catalysis seconday ion mass spectrometry	metal free TEM lamella peraration creation of nanopores localized Noble gas implantation plasmonic applications ion beam mixing

Current projects

FIT4NANO (04/2020-03/2024)

The aim of the Action is to create a coordinated effort in the field of ion beam based nanoengineering that will put European researchers and commercial businesses at the forefront of the quickly moving field of functional nanostructured materials. The Action will unite developers and practitioners of focused ion beam technology to enable them to build the most efficient tool sets and application techniques for the identification, fabrication and characterization of next generation functional nanomaterials. The Action will develop ion sources and instrumentation for the sub 10 nm fabrication and materials analysis. These objectives will be reached through Europe wide networking between researchers from theoretical and experimental groups traditionally not interacting closely. The challenge to overcome is the increasing fragmentation of the FIB landscape between operators of established technologies, developers providing new techniques and methods and designers of functional nanomaterials not aware of the possibilities provided by these emerging focused ion beam technology and methods.

npSCOPE (01/2017-12/2020)

Within the npSCOPE project, a new instrument that couples the extraordinarily high resolution obtained with the finely focussed ion beam provided by a Gas Field Ion Source with sensors for composition (by mass spectrometry) and 3D visualisation (by transmission ion microscopy) will be developed. The tool will allow for an extensive characterisation of individual nanoparticles and their exact location in a given environment (tissue, cells, etc.) leading to a better understanding of their potential risks for human health and/or the environment. Hard- and software based on correlative microscopy approaches along with optimized sample-handling methods will therefore be developed to obtain a complete physico-chemical characterization of nanoparticles.

picoFIB (05/2017-04/2020)

The PicoFIB Network brings together international researchers with an interest in material manipulation and characterisation using novel gas-ion patterning and microscopy. It provides a foundation for knowledge exchange, technical training and research development. Outputs find application across the fields of nano-devices, energy technology and bio-materials. It comprises a series of exchange visits, training events and international workshops.

IONS4SET (02/2016-07/2020)

This projected, which started in February 2016, is aimed at the fabrication of a CMOS compatible single electron transistor that works at room temperature. This bold goal will be achieved by a combination of nanofabrication tehcniques and ion beam techniques. The HIM plays a leading role in this context as we will demonstrate that using the nanosized beam of the HIM we can form a single silicon nano cluster inside a burried SiO₂ layer. After the nano sized beam of the HIM has been used to locally mix Si into SiO₂ the cluster formation will be completed by a thermal treatment.

Analytical Ion Microscopy (finished)

This project led to the development of the worlds first backscatter time of flight spectrometer for the helium ion microscope. The achieved lateral resolution of 50 nm sets new standards for imaging backscatter spectrometry. The design of the spectrometer is such that it is minimal invasive to the microscope and hence ensures that the key performance parameters of the instruments are not influenced in a negative way. In addition the setup can be used for secondary ion mass spectrometry with an even better lateral resolution.

Publications

Recent publications

All publications

2023

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2022

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2021

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