Reconfigurable multiplex setup for high throughput electrical characterisation at cryogenic temperature

Abstract: In this paper, we present a reconfigurable multiplex (MUX) setup that increases the throughput of electrical characterisation at cryogenic temperature. The setup separates the MUX circuitry from quantum device under test (qDUT), allowing qDUT chips to be exchanged easily and MUX chips to be reused. To interface with different types of qDUTs, board-level designs are incorporated to allow interconnects flexibly routed into different topology. MUXs are built based on a multiple level selective gating (MLSG) scheme, where the number of multiplexed output channels (interconnects) is exponentially dependent on the number of control lines. In the prototype setup presented in this paper, with 14 out of 44 existing wires from room temperature, 4 MUXs at cryogenic temperature can supply in total 128 interconnects to interface with qDUTs. We validate the MUX setup operation and assess the various limits existed by measuring k$\Omega$ resistors made of $\mu$m-size graphene ribbons. We further demonstrate the setup by performing charge transport measurement on 128 nm-size graphene quantum devices in a single cooling down.