Superconducting Qubit Control with Single Flux Quantum Pulses: Part I - Fabrication

A large-scale superconducting quantum computer will require significant classical resources for operation, including elements for control, measurement, and feedback. A promising candidate technology to reduce both the wiring heat load and overall system footprint of a future control system is the Single Flux Quantum (SFQ) digital logic family. Here we describe the design and fabrication of an on-chip SFQ pulse driver for control of a superconducting transmon qubit. We discuss optimization of the process flow to preserve the coherence properties of the qubit. Finally, we describe preliminary steps toward the development of a quantum/classical multichip module (MCM) involving a transmon qubit array on one chip and a classical SFQ pattern generator on a second chip, with the two chips coupled in a flip-chip arrangement.