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.
