A ‘Robot Pizza Chef’ Serving Up Better Quantum Computers

At the cluster tool’s hub, a robotic arm shuttles an 8-inch disc called a wafer in and out of the surrounding ring of stations. Some deposit atom-thin layers of material, while others check each step for quality.

“It’s like a robot pizza chef sitting in the middle with a spatula,” said Aeron Tynes Hammack, a Berkeley Lab scientist who works on the cluster tool. “The exciting thing is that it automates processes in a fully clean environment to make complex materials. You can do it very reliably, very reproducibly, and fine-tune the recipes. It gives you insights you would never have if you were human-in-the-loop limited, making one sample at a time.”

By automatically collecting AI-compatible data during quantum device fabrication and linking it to which qubits perform the best, researchers can then apply artificial intelligence to accelerate the search for the best materials, device design, and production methods for the next generation of quantum components.

The QIS cluster tool excels at developing a tiny device at the heart of most quantum computers: the Josephson junction, a sandwich of two superconductors separated by an ultrathin insulating layer. This structure taps into the strange rules of the quantum world: pairs of electrons can “tunnel” through the barrier, even though they don’t have the energy to cross over it in the classical sense.

Josephson junctions are combined with other components to form circuits that act as qubits, the basic units of quantum information. By sending carefully tuned microwave pulses into the circuit, qubits can then be manipulated to perform operations, similar to the bits in classic computers. But because they exploit quantum effects, they are not restricted to a binary set of states, opening the door to new types of computation. As the technology matures, quantum computers could tackle problems that are far too large or complex for today’s machines, such as simulating molecules and optimizing massive networks (like the electric grid, supply chains, or traffic flow).

It’s fitting that a cluster tool specializing in Josephson junctions is now at Berkeley Lab; John Clarke and his fellow laureates conducted their Nobel-Prize winning work on the technology at the lab, building the predecessors of today’s superconducting qubits and paving the way for quantum computing.