Within several projects funded by the German Research Foundation (including the Excellence Cluster ML4Q), building blocks of silicon-based quantum technologies are explored. This includes the fabrication of Si-spin qubits, the realization of coherent coupling between qubits over larger distances across a chip as well as investigations related to classical control electronics. For the realization of Si-based spin qubits, the use of mature CMOS fabrication techniques is studied. Here, a reliable and reproducible fabrication is targeted employing, e.g., spacer-lithography and damascene processes. The ability to fabricate of a large number of coupled quantum dots with high yield and low variability is, for instance, needed in order to realize a so-called quantum bus that potentially enables coupling qubits over larger distances across a chip. As an alternative, the coupling of quantum dots to superconductors is investigated, too. Since semiconductor Spin qubits are realized, manipulated and coupled with several gate electrodes, a classical control electronics operating at cryogenic temperature is required. Such a cryogenic control electronics needs to be operated at very small supply voltages in order to reduce its power consumption. To this end, transistor devices with extremely steep turn-on behavior are necessary. We are currently exploring ways how this can be realized.

Detailed information on Quantum Technology can be found on the Projectwebsite