QLSI - Quantum Large-Scale Integration with Silicon

Quantum computers hold the promise of solving important computational problems beyond the reach of the most powerful supercomputers. It is hoped that quantum computers will help address major societal challenges such as energy, climate, health, and security.

In recent years, significant progress has been made towards the realization of prototype quantum computers. The most advanced are based on superconducting qubits and trapped ions. Despite rapid progress, the question remains whether these approaches will be able to overcome the major challenges of scaling up to many millions of qubits.

Semiconductor spin qubits have emerged as a credible alternative and may be best positioned for ultimate scaling. Spin coherence lasts up to tens of milliseconds, and qubits are relatively resilient to temperature, with several demonstrations at 1 K and above. Perhaps the most compelling attraction of semiconductor spin-qubits is that the clean room processes required to fabricate the quantum dot arrays that host the spins are very similar to those used in today’s transistors.

The mission of QLSI2 is to create a high-level vision and roadmap for the development of semiconductor quantum processors in Europe. With the actors involved in the consortium, we will formulate and execute a roadmap for designing, creating, validating and using Quantum Processing Units (QPU’s), based on semiconductor technology and with clear industrial perspectives for large scale.

At Fraunhofer IPMS, we will be contributing the expertise of our Center Nanoelectronic Technologies. The focus is on utilizing our state-of-the-art 300 mm advanced CMOS cleanroom to provide technology improvement towards scalable quantum computing. The main fields are solid state qubit technologies like superconducting qubits and spin-based semiconductor qubits. Our unique strength is our close relationship with leading semiconductor manufacturers like Infineon, Bosch and GlobalFoundries who are in close vicinity of Fraunhofer IPMS and have been engaged in close mutual projects and partnerships.

Additionally, Fraunhofer IPMS will play a key role in setting up a German R&D pilot fabrication line for solid state qubits together with leading partners from industry, research organizations and academia. 

The QLSI project aims to develop a scalable technology for silicon qubits for quantum computing. Silicon qubits can be driven and read out quickly and are ideally suited for quantum computing due to their small size, high Q-factor and compatibility with industrial manufacturing processes. Silicon qubits have been successfully demonstrated many times; the project is now about developing a scalable technology for later industrial implementation and demonstrating a 16-qubit chip.

With the Center Nanelectronic Technologies, Fraunhofer IPMS contributes a 4000 m² clean room and its expertise in state-of-the-art, industry-compatible CMOS semiconductor manufacturing on 300-mm wafer standard. This concerns, for example, manufacturing processes for nanostructuring, but also material development and electrical control from the CMOS area. In close cooperation with Infineon Dresden, RWTH Aachen University and FZ Jülich, the first qubit demonstrators on wafer level are realized in the project.

To achieve these results, our consortium brings together an unrivalled multidisciplinary team of European groups in academia, RTOs and industry working on silicon-based quantum devices. These groups are committed to playing an active part in developing the industrial ecosystem in silicon-based quantum technologies. QLSI is structured in three enabling toolboxes and one demonstration and scalability activity.

1. The semiconductor toolbox brings together skills from the semiconductor industry such as fabrication, high throughput test and CAD (computer-aided design) with the expertise of the physics community;
2. The quantum toolbox gathers skills from the physics community on spin and quantum properties of Si-based nanostructures and quantum engineering from theory and experience perspectives;
3. The control toolbox gathers teams with instrumentation skills ranging from RF signal generation, automation and set up of high throughput characterization at low temperature.