POST DOC Investigation of CMOS circuitry reliability at deep cryogenic temperatures for quantum com

Leuven - PostDoc
Meer dan twee weken geleden

This post doc position aims to study the reliability of industry-standard CMOS in the 1 K regime, including time-zero and time-dependent variability on dedicated silicon circuits.


Postdoctoral Researcher CMOS circuitry reliability at deep cryogenic temperatures for quantum computing applications

What you will do

Recently, silicon shows to be an appealing platform for implementing spin qubits, due to its integrability with industry-standard CMOS technology [1]. In particular, it provides the advantage that the qubits can be co-integrated with CMOS electronics required for the initialization, manipulation and readout of them. Even though in practice only the qubits need to operate at deep cryogenic temperatures (mKelvin-range), the thermal noise can be further reduced by also operating the (co-integrated) control systems at the same cryogenic environment [2].

These control systems typically consist of integrated analog and RF circuits, which are particularly prone to variability and drift of MOSFET parameters. Currently, models accurately describing variability and degradation, such as hot carrier degradation (HCD [3]) and bias temperature instabilities (BTI [4]) are proven at room temperature and above. However, they are completely untested in state-of-the-art technologies in the 1 Kelvin range.  Reports in the literature on older, more conservative technologies indicate that variability and HCD at cryogenic temperatures increase significantly [5-7]. Moreover, also self-heating of the integrated circuits still takes place at cryogenic temperatures [8]. As a result, the control circuitry might not behave as expected and/or the circuit parameters might drift during operation of the quantum computer.

This work aims to study the reliability of industry-standard CMOS in the 1 K regime, including time-zero and time-dependent variability on dedicated silicon circuits. 
By doing so we expect to achieve the following two goals:
i) The amount of degradation and variability at 1 K operating conditions will be evaluated, enabling design of robust read-out circuits.
ii) The existing reliability models will be tested and extended to the 1 K range, enabling further fundamental insights into the degradation mechanisms and thus bolstering the physical foundations of existing CMOS reliability models.

[1] Pla et al., Nature 489, p. 541 – 545 (2012)
[2] Maurand et al., Nature Comm 7, 13575 (2016)
[4] Grasser T. (Ed.), Bias Temperature Instability for Devices and Circuits, Springer (2015)
[3] Grasser T. (Ed.), Hot Carrier Degradation in Semiconductor Devices, Springer (2015)
[5] Das and Lehmann, Cryogenics 62, pp. 84 – 93 (2014)
[6] Che et al., SSE 50, pp. 959 – 962 (2006)
[7] Song et al., TED 44(2), p. 268 (1997)
[8] Conway Lamb et al., RSI 87, p. 014701 (2016)

What we do for you

We offer you the opportunity to join one of the world’s premier research centers in nanotechnology at its headquarters in Leuven, Belgium. With your talent, passion and expertise, you’ll become part of a team that makes the impossible possible. Together, we shape the technology that will determine the society of tomorrow.
We are proud of our open, multicultural, and informal working environment with ample possibilities to take initiative and show responsibility. We commit to supporting and guiding you in this process; not only with words but also with tangible actions. Through, 'our corporate university', we actively invest in your development to further your technical and personal growth.
We are aware that your valuable contribution makes imec a top player in its field. Your energy and commitment are therefore appreciated by means of a competitive salary.

Who you are

  •  You have a PhD degree in a relevant field
  •  We value your experience in

          - FEOL device reliability 
          - Modeling
          - Electrical characterization
          - Scripting languages e.g. python for reliability model development

  •  We are looking for an enthusiastic and team-oriented candidate. We value your effective communication skills and eagerness to learn and achieve the goals. 
  •  Given the international character of imec, a fluent knowledge of English is necessary. This postdoctoral position is funded by imec through KU Leuven. Because of the specific financing statute which targets international mobility for postdocs, only candidates who did not stay or work/study in Belgium for more than 24 months in the past 3 years can be considered for the position (short stays such as holiday, participation in conferences, etc. are not taken into account).


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