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The Leibniz-Institute for Crystal Growth (IKZ) is a leading research institution in the area of science & technology as well as service & transfer of crystalline materials. Our goal is to enable solutions for urgent societal challenges (e.g. communication, artificial intelligence, climate protection, health etc.). by modern electronic & photonic technologies. The work covers the full spectrum from basic over applied research up to pre-industrial development and is performed in collaboration with national and international partners from university, academy and industry. The institute is part of the Forschungsverbund Berlin ( and a member of the Leibniz Association You can find more details on the institute webpage:

We are offering a

PhD Student Position (m/f/d)

for the topic.

“Microscopic structural characterization of epitaxial Si/SiGe heterostructures”

Semiconductor based electron spin qubits are a promising route towards the realization a quantum processor with scalable architecture which potentially allows to provide a fully error-corrected network with a large number of qubits. Silicon spin qubits offer the advantage to be fabricated using well established routines of semiconductor industry and their high degree of miniaturization. Moreover, such devices provide comparably stable quantum properties and low potential disorder due to the high material quality achievable today.

Individual qubits are formed by electrons confined in electrostatic quantum dots allowing for coherent manipulation of the electron spin state. Both the confinement within a 2D layer as well as removing the p-state degeneracy of electrons in the conduction band are realized via quantum wells (QW) obtained by tensilely strained Silicon that is epitaxially grown between two layers of Si-Ge alloys.

At IKZ, we contribute to the development of SiGe spin-qubits both in terms of growth and characterization of the strained QW heterostructures with the goal to realize highly homogeneous, epitaxial SiGe/Si/SiGe stacks that are suitable for quantum application. For this purpose, we aim to minimize the defect density in the films and understand their origin as well as their impact on the qubit performance. We combine advanced X-ray and electron microscopy techniques to identify individual defects and to map their influence on the structural parameters that determine the qubit potential. The major issues include strain fluctuations due to dislocations and lithographically fabricated gate electrodes, alloy composition fluctuations, inter-diffusion at the interfaces as well as the evolution of these properties in different stages of device fabrication.

The tasks of the PhD student in an international environment will include,

  • Structural and morphological characterization of SiGe-based quantum well hetero-structures using state-of-the-art techniques both at large scale facilities and in IKZ labs
  • Identification of material defects and inhomogeneities that are critical for application
  • Active exchange with a national consortium of research groups developing semiconductor quantum processors
  • Acquire skills in using standard laboratory techniques (eg. XRD, SEM, AFM) as well as analysis and presentation of results
  • Design of strategies for multi-scale imaging of qubit structures combining strain-sensitive synchrotron radiation diffraction and lab-based electron microscopy
  • In particular: development of a fast metrology using non-destructive X-ray microscopy and layout of a high-throughput analysis pipeline for large amount of experimental data


Applicants must hold a master degree either in physics, materials science, chemistry or related disciplines. Prior hands-on experience or skills in the following fields is an asset to your application:

  • X-ray scattering / diffraction or electron microscopy
  • Programming/Software skills (Python / C)
  • Background in semiconductor physics, crystallography and/or elasticity
  • Good English language skills - written and oral
  • Basic knowledge in German language

For information about the project please contact: Dr. Carsten Richter, Tel.: +49(0)30-6392-2859,

What we offer

The position is limited to three years, an extension for another year is possible. Payment is according to TVöD (75%) (Treaty for German public service). The IKZ is an equal opportunity employer and actively supports reconciliation of work and family life. There is equality for applicants of all genders. Qualified women are especially encouraged to apply. Among equally qualified applicants, preference will be given to disabled candidates.

Have we aroused your interest?

Then apply directly by clicking on the “Apply online” button below with a letter of motivation, curriculum vitae and all relevant certificates. The deadline for the application is on 28th of October.

We look forward to receiving your application!