On-chip HEMT amplifiers for semiconductor spin qubit readout

Recent experiments have demonstrated improvements in spin qubit readout using semiconductor-based (HEMT or HBT) amplifiers located adjacent to the qubit chip, at the mixing chamber of a dilution refrigerator. Based on these results, a natural next step is to integrate the amplifier and spin qubit on the same semiconductor chip. For semiconductor spin qubits fabricated using heterostructures supporting high-mobility 2D electron layers (e.g. s-Si/SiGe, GaAs/AlGaAs), fabrication of on-chip HEMTs should be possible. We will discuss progress towards integration of HEMT amplifiers on-chip with quantum dots in GaAs/AlGaAs heterostructures, including design, fabrication, and expected gain and noise performance based on preliminary characterization of HEMT devices. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE, Office of Basic Energy Sciences user facility, and was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories, a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.