We started building the Nanocluster from scratch in 2013, envisioning a versatile tool for multi-material deposition and analysis, and extended it over time. Ten years later, the Nanocluster is one of the biggest multi-material deposition clusters in the world, including 17 interconnected tools for molecular beam epitaxy (MBE), atomic layer deposition (ALD) and material sputtering. It enables the fabrication of unique combinations of a wide range of material systems, including III-V and II-VI semiconductors, metals and superconductors, phase-change materials, oxides and topological insulators. The structures include for example core/shell nanowires, superconductor/TI-based chips, in-situ FET devices.
Furthermore, our approach of interconnected chambers using ultra-high vacuum transfer lines allowed for the installation of several in-situ material characterization techniques such as a scanning electron microscope (SEM) with integrated focused ion beam (FIB) and a scanning tunnelling microscope (STM).
Installation of the Thermal Laser Epitaxy (TLE)
Thermal Laser Epitaxy (TLE) is a brand new and cutting edge technique for the growth of thin films for applications in electronic circuits for the next generation of electronic devices. TLE uses intense and highly focused lasers to locally heat the surface of a free-standing cylinder of pure elemental material, like silicon or tantalum. The laser heats a small portion of the source to high enough temperatures to where the source material begins to become a gas, while the rest of the source remains solid. This gaseous material is then deposited on a substrate like sapphire or silicon as a thin film which then be used in an electronic devices.
A major issue for modern electronics is the purity of the material that one uses to manufacture the circuit: any contamination of the thin films forming the device could significantly change its function or remove any sensitive quantum effects that one is trying to measure. TLE has the advantage in this regard as no indirect heating from external crucibles is required, removing any issues with contamination. TLE also has an unparalleled applicability, being able to deposit any solid, non-radioactive element from across the periodic table. The substrate itself is heated by a laser, allowing for temperatures exceeding 2000C to be easily accessed. This allows for the manufacture of different crystalline compounds that are normally extremely difficult to produce as thin films.
At FZJ, we are looking forward to applying TLE to the field of quantum computing and hope that this technique will help answer some of the material problems facing the field today.