Three-dimensional nanostructures unraveled with ultra-high resolution ion beam analysis

Leuven - PhD
More than two weeks ago

You develop an instrument and methodology to characterize today’s and future nanostructures with unprecedented precision and accuracy


Materials analysis is a cornerstone in the development of new technologies and 3D-nanoelectronic devices and, as such, represents an important area where the semiconductor industry looks at Imec for for innovation and advanced solutions. At present, metrology solutions apt to deal with ultra thin films and 3D-structures are high in demand whereby quantification and non-destructive analysis are critical characteristics. Imec has pioneered such solutions exploiting the properties of (high energy, 2 MeV) ion beam analysis e.g. through Rutherford backscattering spectrometry (RBS). Conceptually the technique is well established whereby the intensity and the energy of the scattered particles from the ion beam impinging on the sample, provides the information about the elements, their concentration, and their depth distribution. When applied to large area or blanket films, ultimate performance in terms of depth resolution (targeting < nm!) is pursued through the exploration of new detectors, data-acquisition electronics and detection schemes combined with advanced data analysis algorithms.

Recently Imec has implemented a unique detector concept with unprecedented depth-resolution, sensitivity and measurement speed, outperforming all other systems worldwide by several orders of magnitude. This concept also contains interesting prospects towards the analysis of 3D-nanostructures by exploiting the idea of array analysis and 3D-tomography.

In this project you will create the fundamental understanding of the underlying physics (scattering geometries, straggling) and its practical implementation (angular divergence of the incoming and scattered ion beam, accelerator ripple, energy straggling, sample roughness, ..) which all affect the performance of the system  in terms of depth resolution and quantification accuracy. Applications such as the analysis of 2D-nanosheets, ultrathin metal stacks for memory applications, or growth modes of ultra thin films, will form the basis of industrially relevant test vehicles.

This work will provide the basis to introduce and establish the concept of ion scattering tomography , the ultimate objective being the 3D-analysis of laterally confined nanostructures. You will design and implement novel spectrometers for that purpose and establish the required data-analysis and data-reconstruction algorithms among others based on machine learning and neural networks.

Within this project you can rely on in-house expertise related to computational 3-dimensional reconstruction of TEM and Atomprobe tomography and will  be engaged in a critical assessment of your results as compared to those obtained with atom probe microscopy and TEM tomography (available in the department).The Ph.D research requires a solid mathematical and analytical background, engineering skills and a swift understanding of the physical principles of the experimental techniques.

Required background: Master physics/chemistry/materials science/nanotechnology

Type of work: 75% Experimental, 25% Theory

Supervisor: Wilfried Vandervorst

Daily advisor: Johan Meersschaut

The reference code for this position is 1812-03. Mention this reference code on your application form.


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