Quantum Motion taps GlobalFoundries for 1024 quantum dot chip

UK quantum computing startup Quantum Motion has shown details of its Bloomsbury quantum chip built in a commercial semiconductor process.

Quantum Motion has designed the chip with an integrated array of 1024 quantum dots (QDs) on an area of less than 0.1mm² and validated them in less than 5 minutes—at least 100 times faster than the current state of the art.

The Bloomsbury chip was fabricated on GlobalFoundries’ 300mm 22FDX platform using  leveraging its industry-leading capabilities such as power-efficient edge processing, wider temperature range to 1K and below and system-on-chip integration. The back gate bias capability of FDX further enables cryogenic tuning and control, providing a significant advantage compared to a bulk silicon process for readout and control operations.

The high speed characterisation uses radio-frequency reflectometry with a typical signal-to-noise voltage ratio in excess of 75 for an integration time of 3.18 μs. The system extracts key quantum dot parameters by using automated machine learning routines to assess the quantum dot yield and understand the impact of device design. 

It uses an all-to-all MUX that enables the selection of a single cell given a 10-bit input. It contains an analogue bus of three device control lines and ten digital address lines (five row-select lines and five column-select lines) to address each QD device under test in a 32 × 32 array. The devices are selectively connected to the analogue bus using CMOS gates integrated within the same silicon as the quantum devices.

This can be extended to more complex unit cells, such as coupled quantum dot systems, the basic building block of semiconductor-based quantum computers. The RF read-out techniques can be used to embed compact dispersive spin qubit read-out with the unit cells of scaled-up QD architectures.

Quantum Motion, backed by Sony, Bosch and Porsche, is developing a spin qubit prototype chip on a 300mm process for the UK’s quantum computer testbed which opened in October 2024.

“Our work with GlobalFoundries has enabled us to demonstrate that scalable manufacturing techniques are compatible with the stringent demands of quantum computing. This achievement shows that silicon-based quantum chips can be fabricated using established semiconductor processes, bridging the gap between quantum research and industrial-scale production,” said James Palles-Dimmock, CEO of Quantum Motion.

“This collaboration is an example of how GlobalFoundries is leveraging its differentiated technologies, such as our 22FDX technology platform, to drive advancements that will help shape the future of quantum computing,” said Ted Letavic, SVP and Corporate Fellow at GlobalFoundries.

“We are extremely encouraged by the results demonstrated by Quantum Motion which show that our process technology and our advanced 22FDX platform are robust enough to enable innovative quantum structures. We look forward to continuing our strong partnership with Quantum Motion to support their vision of a scalable monolithic quantum processor.”

Quantum Motion has developed a technique that can measure each qubit in a large array without needing a vast number of input/output connections to the chip, in the same way that conventional CPUs have billions of transistors interfaced to a motherboard using only a few hundred input/output connections.

The results from Bloomsbury confirm that silicon-based quantum chips are compatible with commercial semiconductor manufacturing processes, addressing key challenges in scaling up quantum computing.

Quantum Motion plans to build on Bloomsbury’s success and the GlobalFoundries partnership with new chip designs with increasing levels of quantum/classical integration.