Diraq Silicon Spin-Qubit Devices (imec 300 mm CMOS)

Overview

Diraq is an Australian company, a spin-out of the University of New South Wales, that is building quantum computers from silicon spin qubits. The idea is to store a qubit in the spin of a single electron trapped in a tiny transistor-like structure, so that quantum chips can be made on the same production lines as ordinary microchips.

Two results define the current state. In September 2025, Diraq and the Belgian research center imec reported in Nature that qubits fabricated on imec's 300 mm industrial platform achieved fidelities above 99% for single- and two-qubit operations. In 2026 the team reported an eight-qubit array made with the same process, four times the size of the earlier unit cell.

History and background

Silicon spin qubits were proposed in the late 1990s. The UNSW group of Andrew Dzurak, from which Diraq was spun out, showed in 2014 that a silicon MOS spin qubit could be controlled with fault-tolerant-level fidelity, and it later demonstrated two-qubit logic gates. Academic devices were made in university cleanrooms, which raised the question of whether performance would survive industrial manufacturing.

The 2025 Nature paper answered that. Diraq-designed devices made at imec showed fidelities above 99% across several nominally identical unit cells on a single 300 mm wafer, with measurement and preparation above 99.9%. Diraq also demonstrated cryogenic CMOS control electronics operating at millikelvin temperatures with its qubits in 2025 and has worked with GlobalFoundries on a 22 nm process. The 2026 eight-qubit array was reported in Nature Communications. Diraq has been selected for stage B of DARPA's Quantum Benchmarking Initiative.

How it works

A silicon spin qubit starts with a layer of silicon, purified so that almost all atoms are the isotope silicon-28, which has no nuclear spin and therefore produces little magnetic noise. Metal gate electrodes on top of the silicon create small electric potential wells called quantum dots, each of which can trap a single electron. The electron's spin, up or down, is the qubit.

Qubit operations use microwave pulses applied to a nearby antenna or gate, which rotate the spin using a technique called electron spin resonance, or through electric fields combined with a magnetic-field gradient. To perform a two-qubit gate, neighboring dots are brought close together and their wavefunctions overlap, which creates an exchange interaction that can entangle the two spins. Readout converts the spin state into a charge movement that a nearby sensor transistor detects.

The big attraction is manufacturing. A quantum dot is not much larger than a modern transistor, and the control electronics can in principle be made on the same chip. Diraq's economic goal is a cost per qubit of well under a dollar at scale, which is a long way from today's research devices but shows why the CMOS approach attracts interest.

Connectivity

Nearest-neighbor exchange coupling in a linear array (eight-qubit array reported in 2026)

Specifications in detail

Key features

• Qubits built with industry-standard 300 mm CMOS manufacturing
• Single- and two-qubit gate fidelities above 99%, repeated across several unit cells on one wafer
• State preparation and measurement above 99.9%
• Eight-qubit linear array reported without loss of coherence compared with the two-qubit cells
• Compatible with cryogenic CMOS control electronics

Limitations

• Qubit counts are small: eight in the largest published array
• Fidelities near 99% are below the best superconducting and trapped-ion results
• Not available to outside users or on any cloud
• Wiring and control for millions of qubits remain a design challenge

Timeline

What it is used for

• Developing a path to chips with millions of qubits using existing semiconductor manufacturing
• Research on integrating qubits with cryogenic control electronics
• Studying error correction on silicon platforms

How it compares

• Compared with superconducting chips like IBM Heron, silicon spin qubits are far smaller in size but have far fewer qubits so far and slightly lower reported fidelities.
• Compared with trapped-ion machines such as Quantinuum H2, they have lower fidelity but a much clearer path to manufacturing at scale.
• Compared with Alice & Bob's cat qubits, they are a solid-state, CMOS-compatible approach rather than a bosonic superconducting one.

Technical notes

This entry replaces an earlier placeholder labeled 'CORE1', which could not be verified against public sources. The facts below come from the peer-reviewed results of Diraq and imec. Each qubit is the spin of a single electron trapped in a quantum dot formed by gate electrodes on a silicon chip. Because the structure resembles a transistor, the same manufacturing lines used for classical processors can produce it.

Why it matters

If silicon spin qubits can keep their fidelity as arrays grow, then the semiconductor industry's manufacturing base becomes available to quantum computing. That is the main attraction: millions of qubits might be built with tools that already exist.

This entry is also a useful example of how database entries should be handled. When a specific product name cannot be verified, it is better to describe the public, peer-reviewed results than to keep unverified specifications.

Frequently asked questions

Keep exploring

• Related processor: IBM Heron (r1, r2, and r3)
• Related processor: Quantinuum H2
• Related processor: Alice & Bob Boson 4 (cat qubit chip)

This profile is written for educational purposes and summarizes company announcements, published papers, and vendor specification sheets. Last reviewed: September 30, 2026. Figures marked as company-reported have not all been independently verified, and benchmarks differ between vendors, so compare them with care.

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