Periodic Reporting for period 3 - IQubits (Integrated Qubits Towards Future High-Temperature Silicon Quantum Computing Hardware Technologies)
Reporting period: 2021-11-01 to 2024-04-30
Quantum computers have the potential to solve computational problems that are unsolvable with the classical computers (including supercomputers) of today, such as the synthesis of new drugs to treat incurable diseases, understanding the secrets of the human brain, and many other open complex challenges in all fields of Science and Technology.
The current qubits are primarily developed in research laboratories and operate at extreme cryogenic temperatures of tens or hundreds milli-Kelvin, with electronic circuits for control and readout that are external to the chip with the qubits.
The extreme cryogenic temperatures and the inherent limitations to the integration due to external electronic circuits, introduce dramatic barriers to the possibility to build actual quantum computers, with thousands and even million integrated qubits and circuits.
The general objective of the project IQubits is to break through these major scientific and technological barriers by developing integrated qubits, control and readout circuits that can operate at higher cryogenic temperatures (i.e. above 1 K) and can be integrated together into the same chip in commercial nanoscale silicon technologies, so paving the way for moving quantum technologies out from research laboratories to semiconductor industry for large-scale fabrication of quantum processors.
IQubits has addressed these major challenges in a full-stack approach at all levels in a multi-disciplinary synergistic effort between EU and Canada, from fundamental quantum principles to modeling, simulation, fabrication and testing of qubit devices and qubit control and readout integrated circuits (ICs) as the fundamental building blocks of future monolithic quantum processors (i.e. integrated on a single chip) in Silicon commercial technologies and operating at higher cryogenic temperatures, paving the way to the quantum technology leap from lab to fab, which is the key step to deliver quantum technology to Society.
The current qubits are primarily developed in research laboratories and operate at extreme cryogenic temperatures of tens or hundreds milli-Kelvin, with electronic circuits for control and readout that are external to the chip with the qubits.
The extreme cryogenic temperatures and the inherent limitations to the integration due to external electronic circuits, introduce dramatic barriers to the possibility to build actual quantum computers, with thousands and even million integrated qubits and circuits.
The general objective of the project IQubits is to break through these major scientific and technological barriers by developing integrated qubits, control and readout circuits that can operate at higher cryogenic temperatures (i.e. above 1 K) and can be integrated together into the same chip in commercial nanoscale silicon technologies, so paving the way for moving quantum technologies out from research laboratories to semiconductor industry for large-scale fabrication of quantum processors.
IQubits has addressed these major challenges in a full-stack approach at all levels in a multi-disciplinary synergistic effort between EU and Canada, from fundamental quantum principles to modeling, simulation, fabrication and testing of qubit devices and qubit control and readout integrated circuits (ICs) as the fundamental building blocks of future monolithic quantum processors (i.e. integrated on a single chip) in Silicon commercial technologies and operating at higher cryogenic temperatures, paving the way to the quantum technology leap from lab to fab, which is the key step to deliver quantum technology to Society.
In the first year (12 months), we designed the preliminary qubits, control and readout circuits in a commercial nanoscale Silicon technology, for operations a few Kelvin (e.g. 2 K and possibly beyond). We identified the methodology about how to design these integrated qubits and circuits, as well as how to design more advanced and smaller qubits with 10nm characteristic dimension than those that can be fabricated today (22 nm) with the most advanced industrial Silicon technology process that we believe has the capability to be a most suitable technology process for the implementation of future integrated quantum processors. We started the development of the nanofabrication technology processes necessary for the fabrication of the advanced qubits capable of operating at higher temperature. At the same time, we started the implementation of advanced simulation software capable of accounting for quantum effects at atomic scale, which are not taken into account in the current device and circuit design simulators.
In the second period (18 months), we simulated, designed, fabricated and tested experimentally the preliminary qubits and qubit circuits in commercial nanoscale Silicon technology. The experimental measurements have shown that the transistors of some of advanced nanoscale commercial technologies provide clear evidences of quantum effects at cryogenic temperatures above 2 K. Also, verified that the design methodology for qubit control and readout ICs provides an effective design strategy for frequency operations up to 220 GHz. A large set of innovative building blocks have been designed, fabricated and tested with success, and their designs validated for the implementation of the final versions. Among these, it is worth emphasizing the successful implementation of a new class of low-power high-frequency ICs featuring a small form factor (i.e. comparable with the qubit dimensions) that, for this reason, has been named as low-power qubit-size integrated circuits, which are of strategic importance for the implementation of monolithic Silicon quantum processors. The development of nano-fabrication processes for ultra-scaled devices with 10nm characteristic dimension continued with promising results.
In the third period (30 months), we studied, simulated, modeled, designed, fabricated and tested several single, double and triple quantum-dot (QD) devices in commercial and research nano-fabrication facilities Silicon and III-N semiconductor technologies. The measurements on the Silicon QD devices have shown clear signatures of quantum effects and excellent yield. Complex measurement setups were designed and implemented to analyze further in detail the quantum properties and functionality of the fabricated qubit devices.
The work carried out has been actively disseminated in renowned international journals and global forums (conferences, workshops and seminars), as well as through invited lectures and presentations in academic,research and industrial institutions in four continents (Europe, America, Oceania and Asia).
The developed software, nano-fabrication processes, qubit devices, qubit control and readout circuits, design methodologies, measurement setups and test methodologies have shown a high potential for future exploitation of the know-how through potential licensing, creation of start-up companies, pilot lines and strategic academic-industrial partnerships and collaborations.
In the second period (18 months), we simulated, designed, fabricated and tested experimentally the preliminary qubits and qubit circuits in commercial nanoscale Silicon technology. The experimental measurements have shown that the transistors of some of advanced nanoscale commercial technologies provide clear evidences of quantum effects at cryogenic temperatures above 2 K. Also, verified that the design methodology for qubit control and readout ICs provides an effective design strategy for frequency operations up to 220 GHz. A large set of innovative building blocks have been designed, fabricated and tested with success, and their designs validated for the implementation of the final versions. Among these, it is worth emphasizing the successful implementation of a new class of low-power high-frequency ICs featuring a small form factor (i.e. comparable with the qubit dimensions) that, for this reason, has been named as low-power qubit-size integrated circuits, which are of strategic importance for the implementation of monolithic Silicon quantum processors. The development of nano-fabrication processes for ultra-scaled devices with 10nm characteristic dimension continued with promising results.
In the third period (30 months), we studied, simulated, modeled, designed, fabricated and tested several single, double and triple quantum-dot (QD) devices in commercial and research nano-fabrication facilities Silicon and III-N semiconductor technologies. The measurements on the Silicon QD devices have shown clear signatures of quantum effects and excellent yield. Complex measurement setups were designed and implemented to analyze further in detail the quantum properties and functionality of the fabricated qubit devices.
The work carried out has been actively disseminated in renowned international journals and global forums (conferences, workshops and seminars), as well as through invited lectures and presentations in academic,research and industrial institutions in four continents (Europe, America, Oceania and Asia).
The developed software, nano-fabrication processes, qubit devices, qubit control and readout circuits, design methodologies, measurement setups and test methodologies have shown a high potential for future exploitation of the know-how through potential licensing, creation of start-up companies, pilot lines and strategic academic-industrial partnerships and collaborations.
The results show - for the first time - that the QD devices implemented in the commercial 22nm Silicon technology process, show superior quantum effects at cryogenic temperatures of a few Kelvin. An effective design methodology for innovative ICs has been developed and proven experimentally.
New software solutions, nanofabrication processes and measurement setups have been developed to prove the feasibility, properties and performances of advanced qubit device structures and circuits of future integrated quantum processors that can operate at higher temperature, and can be designed with advanced software tools and fabricated on industrial scale.
In continuation with the important results emerged at the end of the project, further experimental tests will allow us to prove the feasibility of further advanced semiconductor qubits (i.e. beyond the original plans) that together with the control and readout circuits fabricated on the same chip, will pave the way to the future monolithic quantum processors operating at acceptable cryogenic temperatures, so allowing the leap of quantum technologies to the industrial production scale.
Despite the future challenges, IQubits has had a the profound impact on the quantum technology hardware developments. The results emerged so far, in many respect innovative, groundbreaking and well beyond the state of the art, despite in some regard they may require still further experimental proofs beyond those already achieved, have convinced the semiconductor industry to start working on the technology process developments. Moreover, semiconductor qubit start-ups in EU, US, Oceania and elsewhere are now following our approach, exploring qubits and qubit arrays in 22nm FDSOI CMOS, i.e. technology first-developed in EU. Therefore, with its pioneering developments, IQubits has greatly concurred so far to secure a leading position of the EU's research and innovation on Quantum Technologies, which will have a pivoting role on future societal and economical transformations world-wide.
New software solutions, nanofabrication processes and measurement setups have been developed to prove the feasibility, properties and performances of advanced qubit device structures and circuits of future integrated quantum processors that can operate at higher temperature, and can be designed with advanced software tools and fabricated on industrial scale.
In continuation with the important results emerged at the end of the project, further experimental tests will allow us to prove the feasibility of further advanced semiconductor qubits (i.e. beyond the original plans) that together with the control and readout circuits fabricated on the same chip, will pave the way to the future monolithic quantum processors operating at acceptable cryogenic temperatures, so allowing the leap of quantum technologies to the industrial production scale.
Despite the future challenges, IQubits has had a the profound impact on the quantum technology hardware developments. The results emerged so far, in many respect innovative, groundbreaking and well beyond the state of the art, despite in some regard they may require still further experimental proofs beyond those already achieved, have convinced the semiconductor industry to start working on the technology process developments. Moreover, semiconductor qubit start-ups in EU, US, Oceania and elsewhere are now following our approach, exploring qubits and qubit arrays in 22nm FDSOI CMOS, i.e. technology first-developed in EU. Therefore, with its pioneering developments, IQubits has greatly concurred so far to secure a leading position of the EU's research and innovation on Quantum Technologies, which will have a pivoting role on future societal and economical transformations world-wide.