  Building a fault-tolerant quantum computer will require vast numbers of
physical qubits. For qubit technologies based on solid state electronic
devices, integrating millions of qubits in a single processor will require
device fabrication to reach a scale comparable to that of the modern CMOS
industry. Equally importantly, the scale of cryogenic device testing must keep
pace to enable efficient device screening and to improve statistical metrics
like qubit yield and voltage variation. Spin qubits based on electrons in Si
have shown impressive control fidelities but have historically been challenged
by yield and process variation. Here we present a testing process using a
cryogenic 300 mm wafer prober to collect high-volume data on the performance of
hundreds of industry-manufactured spin qubit devices at 1.6 K. This testing
method provides fast feedback to enable optimization of the CMOS-compatible
fabrication process, leading to high yield and low process variation. Using
this system, we automate measurements of the operating point of spin qubits and
probe the transitions of single electrons across full wafers. We analyze the
random variation in single-electron operating voltages and find that the
optimized fabrication process leads to low levels of disorder at the 300 mm
scale. Together these results demonstrate the advances that can be achieved
through the application of CMOS industry techniques to the fabrication and
measurement of spin qubit devices.
