Cryogenic CMOS circuits for quantum computing (multiple thesis topics)

Quantum computers hold the promise to efficiently solve problems that are intractable by classical computers today, such as large number factorization and simulation of quantum systems, by exploiting quantum phenomena for computation. State-of-the-art solid-state quantum processors must be cooled at cryogenic temperatures to preserve quantum behaviour. In addition, quantum processors require an electronic interface to both control and read out the quantum bits (qubits). Such electronic interface must also operate at cryogenic temperature to enable practical connections to the thousands of qubit envisioned in future quantum computers. The electronic interface spans from the digital to the analog domain and comprises several analog and mixed-signal components, such as data converters, voltage/current references and low-noise amplifiers.

Several M.Sc. thesis projects will be defined, each focusing on a circuit componetn.

The objective of each of those projects is the design and implementation of a CMOS analog/mixed-signal circuit component for the use in the electronic interface for quantum processors and operating at cryogenic temperatures close to the quantum processor. While prior works has demonstrated the functionality of CMOS devices at cryogenic temperature, the challenge will be to design of circuits operating at temperatures as low as 4 K and below and achieving performance comparable with state-of-the-art designs operating at room temperature. The project will include analog circuit design (schematic and layout) and characterization of the fabricated circuit.

The project will comprise the following phases, partially or fully, depending on execution speed and time constraints:

• Literature review on cryo-CMOS and specific circuit architectures (2 weeks)
• System analysis and choice of best architecture (10 weeks)
• Circuit design in 40-nm CMOS (12 weeks)
• Layout of test chip (8 weeks)
• Preparation of measurement setup (PCB, instrument automation) (2 weeks)
• Measurement and analysis of performance (6 weeks)
• Writing of report (4 weeks)

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Last modified: 2023-01-30