A Millikelvin CMOS Demultiplexing Chip for Scalable Qubit Addressing

Large-scale silicon qubit control requires accurate biasing and gate pulsing for several terminals of a multi-qubit device. Continuous pulsing enables sequential quantum operations, while simultaneous pulsing on multiple terminals enables real-time cross-talk compensation. Conventional qubit addressing provides DC bias and gate pulsing using commercial instruments at 300 K, while recent innovation in cryo-CMOS control can move select signal generation to 4 K. In both approaches however, cabling, power and noise constraints becomes a bottleneck for controlling large qubit/SET arrays. To address the cabling bottleneck, certain aspects of the control system should be moved closer to the qubits at the mK stage.

In this work, we present a mK cryo-CMOS demultiplexer chip that uses a single DC bias generator and a single pulse generator as inputs, to demultiplex voltages for up to 64 qubit device terminals and provide both DC bias, and simultaneous and continuous high-speed gate pulses. To further alleviate cabling bottlenecks, a 4 K cryo-CMOS controller provides the control signals and gate pulsing voltage to the mK demultiplexer. Integrated with a foundry manufactured qubit chip on the same PCB, mK cryogenic measurements show multi-terminal characterization of a qubit device.