Ferraris, A.Cha, E.Mueller, P.Morf, T.Prathapan, M.Sousa, M.Han, H. -C.Enz, C.Zota, C. B.2023-06-052023-06-052023-06-052022-01-0110.1109/IEDM45625.2022.10019536https://infoscience.epfl.ch/handle/20.500.14299/197935WOS:000968800700192We demonstrate cryogenic switching devices based on HEMT technology for scalable quantum computer (QC) control and readout signal routing. The switches are implemented in a quantum well network design without metal contacts between gates, and exhibit extremely steep cryogenic subthreshold swing of similar to 5 mV/decade, fast switching, along with on/off ratio of 10(7) and isolation leakage of 10 pA/mu m. The use of a Pt gate metal layer that diffuses into the gate barrier is shown to significantly enhance subthreshold properties. The results indicate that HEMT-based switching circuits could offer advantages over Si CMOS at cryogenic temperatures for future high-density ultra-low power QC signal routing.Engineering, Electrical & ElectronicEngineeringtext::conference output::conference proceedings::conference paper