(Invited) Superconducting Qubits and Superconducting Digital Electronic Circuits on 300mm Wafers

Superconducting qubits have made great strides over the past decade, as evidenced by the announcement of 17-qubit and 50-qubit chips towards the end of 2017. The promise of quantum computing for solving problems of interest to society (such as complex drug design, and cryptography for national security, etc.) can be significantly advanced by the fabrication of qubits with high performance characteristics that faithfully replicate the designer's intent. Additionally, energy-efficient ways with low latency to control qubits at millikelvin temperatures are being researched. Superconducting digital electronics are one such approach, which can be 3D-integrated with qubits, with appropriate care taken to avoid quasi-particle poisoning of qubits. In this presentation, the potential advantages and challenges of qubit and superconducting electronics fabrication using advanced 300mm wafer processes will be discussed, followed by a review of millikelvin characterization results from qubits fabricated using 193nm lithographic techniques on 300mm wafers. The selection of materials, and formation of high quality interfaces during the fabrication of superconducting structures will be discussed, along with high resolution transmission electron microscopy and other analyses that guide such process development – these serve to illustrate the potential for achieving further increases in coherence time and qubit frequency control through the use of advanced 300mm fabrication and characterization techniques. The development of ‘manufacturing-friendly’ qubit architectures is essential to enable the creation of well-controlled qubits, as would be required to tackle practical computational problems of interest. Some of the approaches to ‘manufacturing-friendly’ qubit fabrication under consideration at SUNY Poly will be discussed, along with their 3D integration with control circuits and readout mechanisms.