Growth of high-purity silicon crystals by the Czochralski method using magnetic fields – for Einstein telescope mirror substrates

Supervisor: Priv.-Doz. Dr. R. Radhakrishnan Sumathi

Institution:
Leibniz-Institut für Kristallzüchtung (IKZ), Berlin

Bewerbungsfrist: August 17, 2026

Silicon (Si) single crystals are indispensable in microelectronics and power electronics. They are also a leading candidate material for the test mass mirrors of the proposed Einstein Telescope (ET), a next-generation underground gravitational-wave observatory. As a partner in the ET collaboration, our research focuses on the growth of ultra-high-purity, high-quality bulk Si single crystals using advanced melt-growth techniques. The goal is to develop Si mirror substrates with exceptional optical properties that enable the higher sensitivity required for the ET interferometer. In this BMFTR-funded research project, we aim to establish a novel magnetic field assisted Czochralski (MCz) crystal growth process to produce ultra-pure, high-quality Si single crystals with extremely low optical absorption.

As a doctoral research student, you will contribute to the development and optimization of this innovative crystal growth process. Your research will involve detailed investigations of melt growth dynamics, reduction of contamination originating at the crucible–melt interface, and approaches to further improving crystal purity. You will study the influence of melt convection on impurity transport from the crucible to the growing crystal and develop advanced methodologies to achieve the stringent material quality required for the application.

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