CMOS and beyond CMOS
Discover why imec is the premier R&D center for advanced logic & memory devices. anced logic & memory devices.
Connected health solutions
Explore the technologies that will power tomorrow’s wearable, implantable, ingestible and non-contact devices.
Life sciences
See how imec brings the power of chip technology to the world of healthcare.
Sensor solutions for IoT
Dive into innovative solutions for sensor networks, high speed networks and sensor technologies.
Artificial intelligence
Explore the possibilities and technologies of AI.
More expertises
Discover all our expertises.
Be the first to reap the benefits of imec’s research by joining one of our programs or starting an exclusive bilateral collaboration.
Build on our expertise for the design, prototyping and low-volume manufacturing of your innovative nanotech components and products.
Use one of imec’s mature technologies for groundbreaking applications across a multitude of industries such as healthcare, agriculture and Industry 4.0.
Venturing and startups
Kick-start your business. Launch or expand your tech company by drawing on the funds and knowhow of imec’s ecosystem of tailored venturing support.
/Job opportunities/Reliability-physics based hardware primitives for tamper-free cryptographic applications

Reliability-physics based hardware primitives for tamper-free cryptographic applications

PhD - Leuven | More than two weeks ago

Improving IC security by understanding and exploiting their degradation features.

​Cryptographic algorithms and protocols are essential for protection of data during storage, transmission and processing. Research challenges in this domain rely in developing more lightweight solutions (e.g. for low power and cost IoT applications) as well as improving robustness against post-quantum threats (hypothetical attacks by computationally powerful systems).

Utilizing dedicated hardware implementations for typical security primitives is advantageous as it offers an extremely strong root of trust. Some of such hardware-based roots of trust recently gaining a lot of attention are physically unclonable functions (PUF), true random number generators (TRNG) and “silicon odometers”.

A PUF provides a chip with a unique static feature, i.e. a chip fingerprint, which cannot be remanufactured and hence can be used to identify this specific chip. Conventionally, a PUF harvests the static entropy from random process variation of the devices or interconnects, to generate the unique chip fingerprint. On the other hand, the entropy in TRNG is harvested from the dynamic stochastic processes occurring during operation, such as thermal noise and charge trapping.

A reliable age monitoring system can be provided by understanding the deterministic features of IC degradation (analogous to odometers in cars that indicate the wear and tear on the vehicle) to prevent chip recycling and reselling. In other words, one can derive the actual usage of the chip, i.e. distinguishing chips that might have been unused in storage from those that might have been overused, e.g., by overclocking.

Although some implementations of silicon odometers have been proposed using degradation mechanisms such as Biased Temperature Instability (BTI), Hot-carrier Injection (HCI) or Electromigration (EM) [1-2], these implementations, however, do not provide resilience against tampering. Since most of the degradation mechanisms can be recovered to some extent, vectors may exist for tampering the recorded aging information. One example is the odometer based on ring oscillators (RO)--the oscillation frequency can reflect the amount of hot-carrier injection (HCI) degradation caused by operation. HCI degradation typically only worsens with time, but can be also partially reversed by a tamperer due to an effect called thermal curing (e.g., by baking the chip at high temperature).

The student candidate will perform a comprehensive study on the reliability physics and investigate different types of degradations, allowing to exploit degradation features to conceive hardware primitives for PUFs or TRNGs, or to develop more precise silicon odometers and elaborate robust countermeasures for physical tampering.

  • Ref. 1: J. Keane, X. Wang, D. Persaud, C.H. Kim. 2010. An All-In-One Silicon Odometer for Separately Monitoring HCI, BTI, and TDDB. In IEEE Journal of Solid-State Circuits, vol. 45, no. 4, pp. 817-829.
  • Ref. 2: X. Wang, J. Keane, T.T. Kim, P. Jain, Q. Tang, C.H. Kim. 2014. Silicon Odometers: Compact In Situ Aging Sensors for Robust System Design. in IEEE Micro, vol. 34, no. 6, pp. 74-85

KU Leuven supervisor: Guido Groeseneken (KU Leuven)
Location: Leuven
Focus of work: Devices; Circuit Design; Metrology & characterization 

The reference code of this topic is 2021-041. Please mention this on your application.

The next application window will be open from mid-March 2021 until mid-April 2021.
It is not possible to send in your application before mid-March 2021.