Advanced DC and RF electrical characterisation of passive and active components in 28nm-FDSOI technology at cryogenic temperature

Defense of doctoral thesis by  Quentin BERLINGARD, for the  University  Grenoble Alpes, speciality  " OPTIC & RADIOFREQUENCIES  "

Keywords :
Q-ENG on silicon,cryogenics,electrical characterisation,Radio-frequency,FDSOI

Abstract :
The operation of electronic circuits and devices at cryogenic temperatures is generating increasing interest in fields such as aerospace and high-performance computing, where it is well established that electronic device performance significantly improves at lower temperatures. Recently, the rise of quantum computers, which integrate quantum bits, or qubits, along with their readout and control electronics, has further heightened the appeal of cryogenic electronics, leading to a remarkable resurgence in this area. Electronic circuits capable of operating at these extreme temperatures and reaching radio frequencies (RF) are proliferating. However, there remains a significant lack of reliable models to accurately describe passive and active devices under these conditions, particularly in the RF frequency range.
Among the technologies being explored, FD-SOI stands out for its high-performance passive circuits and transistors, known for their low power consumption, adaptability to RF applications, and fine control of threshold voltage through a back-gate. While many characterization studies at low temperatures have been conducted in direct current (DC), RF characterization remains scarce. However, studying devices in RF provides a complementary perspective, offering deeper insights into the physical effects specific to cryogenic temperatures.
In this thesis, we propose a comprehensive approach to the characterization and modeling of passive and active components using 28nm FD-SOI technology, over a temperature range from ambient to cryogenic conditions down to 4.2K. This approach includes the development of a dedicated measurement setup and a methodology for RF characterization at low temperatures, followed by a detailed analysis of devices operating in cryogenic conditions. RF measurements will complement existing DC data, with the aim of enhancing our understanding of the physical phenomena at low temperatures and developing accurate models. These characterizations will then be used to optimize the performance of electronic circuits designed to operate in cryogenic environments.

Jury members :

• Mikaël CASSE, RESEARCH DIRECTOR - CEA - Centre de Grenoble : Supervisor
• Bogdan CRETU, ASSISTANT PROFESSOR HDR - Normandie Université : Reviewer
• Jean-Michel SALLESE, ASSISTANT PROFESSOR - Ecole Polytechnique Fédérale de Lausanne : Reviewer
• Philippe FERRARI, PROFESSOR UNIVERSITY- Université Grenoble Alpes : Examiner
• Valeriya KILCHYTSKA, SCIENTIST - Université Catholique de Louvain : Examiner
• Sylvain BOURDEL,  PROFESSOR UNIVERSITY - Grenoble INP - UGA : Examiner