PhD Position Cryo-CMOS Circuit Design for Optical Communication in Quantum Computers

Are you ready to shape the future of quantum technology? Join our vibrant team in designing and demonstrating cryo-CMOS integrated circuits to interface quantum computers and quantum sensors!

Job description
Quantum computers promise to solve problems intractable by classical digital computers, while quantum sensors can offer unprecedented accuracy and sensitivity in detecting very small quantities. However, quantum devices typically operate at cryogenic temperatures, thus requiring long, bulky, and unreliable wires to connect to their room-temperature control electronics. This wiring bottleneck hinders the system's scalability and performance. As a PhD student in Electrical Engineering at TU Delft, you will overcome this bottleneck by building the cryogenic interface for future quantum systems.

In our group, we have pioneered the use of CMOS integrated circuits operating at cryogenic temperatures (cryo-CMOS). We adopt standard CMOS technologies to exploit their large-scale integration, as required in future large-scale quantum computers and cryogenic sensors, and their performance. CMOS devices are functional at temperatures as low as 4 K and below, but their behaviour is very different than at room temperature, including an increased threshold voltage, a higher driving current, and a lower thermal noise. The challenges lie in exploiting the advantages of cryogenic operation, such as the lower thermal noise, while circumventing device non-idealities by inventing innovative circuit architectures and systems that can outperform the state-of-the-art. Although we have demonstrated several high-performance cryo-CMOS circuits and systems in the last decade, your challenge will be demonstrating new functionalities and pushing the boundary of circuit performance and knowledge.

In this project, you will address a crucial challenge in quantum computers: how to efficiently transfer a large amount of digital data in and out of a cryogenic refrigerator? The quantum processor will operate in a closed chamber cryogenically refrigerated, thus requiring the transfer of both the input data and the computation results in and out of such a cryogenic chamber over a distance of up to a few meters. While electrical communication via conducting wires seems the straightforward solution, this approach suffers from several limitations, including generating electromagnetic interference and the limited data bandwidth of electrical interconnects. Furthermore, electrical conductors also conduct heat, thus occupying part of the cooling budget of the cryogenic refrigerator. Optical communication presents then a promising alternative thanks to the low thermal conductance of optical fibers and the excellent performance in terms of interference and data rate. Your research will aim to demonstrate the first cryo-CMOS optical transceiver. You will identify the best optical-electrical transducer to operate at cryogenic temperatures and design the cryo-CMOS electric interface to transmit and receive high-speed digital data. Over the course of your PhD, you will design several prototypes of cryo-CMOS temperature sensors, tape them out in advanced CMOS technologies, and characterize the resulting prototypes in our advanced cryogenic electrical characterization laboratory.

Your results will advance the state-of-the-art in cryo-CMOS circuit design and will result in presentations at top conferences for the advances of integrated circuits and publications in high-impact scientific journals. Your cryo-CMOS temperature sensor will be integrated into the larger prototypes developed at TU Delft and our industrial partners, thus achieving a real impact in the field of quantum technologies.

Job requirements

• A MSc degree in Electrical Engineering or a related field.
• Strong interest and strong background in analog circuit design; any practical experiences in circuit design, either in academia or industry, is a plus, but not a necessity.
• Good analytical, creativity and problem-solving skills.
• Excellent communication skills in English, both written and oral.
• Ability and eagerness to work in an international collaborative environment.

TU Delft (Delft University of Technology)
Delft University of Technology is built on strong foundations. As creators of the world-famous Dutch waterworks and pioneers in biotech, TU Delft is a top international university combining science, engineering and design. It delivers world class results in education, research and innovation to address challenges in the areas of energy, climate, mobility, health and digital society. For generations, our engineers have proven to be entrepreneurial problem-solvers, both in business and in a social context.

At TU Delft we embrace diversity as one of our core values and we actively engage to be a university where you feel at home and can flourish. We value different perspectives and qualities. We believe this makes our work more innovative, the TU Delft community more vibrant and the world more just. Together, we imagine, invent and create solutions using technology to have a positive impact on a global scale. That is why we invite you to apply. Your application will receive fair consideration.

Challenge. Change. Impact!

Faculty of Electrical Engineering, Mathematics and Computer Science
The Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) brings together three scientific disciplines. Combined, they reinforce each other and are the driving force behind the technology we all use in our daily lives. Technology such as the electricity grid, which our faculty is helping to make completely sustainable and future-proof. At the same time, we are developing the chips and sensors of the future, whilst also setting the foundations for the software technologies to run on this new generation of equipment – which of course includes AI. Meanwhile we are pushing the limits of applied mathematics, for example mapping out disease processes using single cell data, and using mathematics to simulate gigantic ash plumes after a volcanic eruption. In other words: there is plenty of room at the faculty for ground-breaking research. We educate innovative engineers and have excellent labs and facilities that underline our strong international position. In total, more than 1000 employees and 4,000 students work and study in this innovative environment.

Click here to go to the website of the Faculty of Electrical Engineering, Mathematics and Computer Science.

Conditions of employment
Doctoral candidates will be offered a 4-year period of employment in principle, but in the form of 2 employment contracts. An initial 1,5 year contract with an official go/no go progress assessment within 15 months. Followed by an additional contract for the remaining 2,5 years assuming everything goes well and performance requirements are met.

Salary and benefits are in accordance with the Collective Labour Agreement for Dutch Universities, increasing from € 2901 per month in the first year to € 3707 in the fourth year. As a PhD candidate you will be enrolled in the TU Delft Graduate School. The TU Delft Graduate School provides an inspiring research environment with an excellent team of supervisors, academic staff and a mentor. The Doctoral Education Programme is aimed at developing your transferable, discipline-related and research skills.

The TU Delft offers a customisable compensation package, discounts on health insurance, and a monthly work costs contribution. Flexible work schedules can be arranged.

Will you need to relocate to the Netherlands for this job? TU Delft is committed to make your move as smooth as possible! The HR unit, Coming to Delft Service, offers information on their website to help you prepare your relocation. In addition, Coming to Delft Service organises events to help you settle in the Netherlands, and expand your (social) network in Delft. A Dual Career Programme is available, to support your accompanying partner with their job search in the Netherlands.

Additional information
If you would like more information about this vacancy or the selection procedure, please contact Fabio Sebastiano, via f.sebastiano@tudelft.nl.

Application procedure
Are you interested in this vacancy? Please apply no later than 30 March 2025 via the application button and upload your CV and cover letter describing your interest in this specific position and why you think you are the suitable candidate for this specific position.

You can address your application to Fabio Sebastiano.

Doing a PhD at TU Delft requires English proficiency at a certain level to ensure that the candidate is able to communicate and interact well, participate in English-taught Doctoral Education courses, and write scientific articles and a final thesis. For more details please check the Graduate Schools Admission Requirements.

Please note:

• You can apply online. We will not process applications sent by email and/or post.
• A pre-employment screening can be part of the selection procedure.
• For the final candidates, a knowledge security check will be part of the application procedure. For more information on this check, please consult Chapter 8 of the National Knowledge Security Guidelines. We carry out this check on the basis of legitimate interest.
• Please do not contact us for unsolicited services.

36 - 40 hours per week

Mekelweg 5