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Offers : 111

Adaptive CMOS Image Sensor for smart vision systems

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Start date : 1 October 2019

offer n° SL-DRT-19-0335

The aim of this thesis is to explore new kind of smart vision sensor architectures using for enhance the sensor reactivity and for simplify the image processing. The studied vision system will use new 3D microelectronic technologies from CEA-leti. These technologies are capable to stack several integrated circuits. The main advantage is to propose a high density of interconnections between them, allowing connection at the pixel level. This characteristic allows us to think about a totally new architecture of the image processing chain of a basic imager (readout, amplification, compensation, colorization, tone mapping) in order to improve the agility, a better image quality, a better energy efficiency, with a low silicon footprint.

The PhD student will benefit during his 3-years thesis of the expertise and the scientific excellence of the CEA leti to attend objectives with a high level of innovation through international patents and publications.

The dynamic and autonomous candidate, will have a microelectronic master degree, specialized in analog integrated circuit design. A good knowledge of circuit design CAD tools will be important (Cadence, and also Matlab) and good knowledge in image processing will be appreciated.

This thesis will start with the state of the art study, then the PhD student will define the optimal architecture. Finally, a test chip will be designed and tested. It will demonstrate the scientific and industrial potentialities of the proposed solutions.

  • Keywords : Engineering science, Computer science and software, Electronics and microelectronics - Optoelectronics, DACLE, Leti
  • Laboratory : DACLE / Leti
  • CEA code : SL-DRT-19-0335
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SPAD Imager for HDR ToF using multimodal data fusion

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Start date : 1 October 2019

offer n° SL-DRT-19-0301

Depth sensors are currently a very high trending topic. Indeed, in the fields of autonomous vehicles, portable electronic devices and the Internet of Things, new technology enablers now tend to provide handy 3D image data for future innovative end-user applications. There is a great diversity of 3D sensor types, either using passive imaging (depth from defocus, stereovision, phase pixels…) or using active imaging (ultrasounds, structured light, Time-of-Flight…). Each of these systems addresses specifications in terms of depth dynamic range (accuracy of the measurement versus maximum distance). In this thesis, we will study the specific case of Single Photon Avalanche Diodes (SPAD). Recent scientific results regarding this electro-photonic component demonstrate its relevance in the context of Time-of-Flight (ToF) imaging, especially in the case of integration in a 3D-stacked design flow exhibiting a pixel pitch of the order of ten micrometers. However, the nature of the data gathered by this type of component requires significant signal processing within the sensor to extract relevant information. This thesis will aim to revise traditional approaches related to histogram processing by directly extracting statistical features from raw data. Depending on the background and skills of the PhD candidate, two research axes would be investigated. First, on the hardware side, possible modifications of SPAD based sensor architecture in order to provide “augmented” multi-modal information. Second, on the theoretical and algorithmic side, data fusion methods to improve the final reconstruction rendering of depth maps from sensed data.

  • Keywords : Engineering science, Electronics and microelectronics - Optoelectronics, Mathematics - Numerical analysis - Simulation, DACLE, Leti
  • Laboratory : DACLE / Leti
  • CEA code : SL-DRT-19-0301
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Core-shell perovskite nanocrystals for photovoltaic applications

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Start date : 1 October 2020

offer n° SL-DRF-19-0446

Halogenated perovskite materials have recently created a sensation in the field of photovoltaics and other optoelectronic applications because of the very high efficiencies obtained. Colloidal nanocrystals (NCs) of the perovskites have very recently attracted a lot of attention because of their unique optical properties, very high quantum yields and simple synthesis. The use of the perovskite NCs for the solar energy applications is limited today by their toxicity (they contain lead) and lack of stability. In the framework of the PhD project we propose for the first time to tackle both of these problems by synthesizing core-shell NCs with the inorganic perovskite core (based on Pb or Bi) and a lower crystalline dimensionnality perovskite shell (Cs3Bi2X9 or other 0D, 1D, 2D analogues). The shell will protect photoactive core and will limit (or eliminate completely) the toxicity. These systems will be studied by the advanced techniques available at the CEA or though ongoing international collaborations. The thin film or sensitized solar cells based on the best core-shell perovskite NC heterostructures will be fabricated and tested.

  • Keywords : Chemistry, Ultra-divided matter, Physical sciences for materials, INAC, SyMMES
  • Laboratory : INAC / SyMMES
  • CEA code : SL-DRF-19-0446
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Superconductor / Semiconductor hybrid nanostructures based on Germanium for quantum information

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Start date : 1 October 2019

offer n° SL-DRF-19-0565

Holes in germanium have the advantage to possess a strong spin-orbit coupling enabling fast electrical control of their spin. In addition, p-type germanium has the tendency to form low-Schottky-barrier contacts with several metals, including superconducting ones. This opens the opportunity to realize novel hybrid superconductor-semiconductor devices relying on the superconducting proximity effect in germanium.

The goal of this project is to fabricate and study nano-devices embedding a 2D hole gas confined to a germanium well. More specifically, we aim at realizing quantum-dot and quantum-wire nanostructures in which individual hole spins are electrically controlled by means of electrostatic gates. Then we plan to connect such nanostructures to superconducting electrodes to obtain novel types of high-quality hybrid devices such as gate-tunable transmons, i.e. “gatemons”.

Two types of germanium layers will be studied: high-mobility, strained-Ge quantum wells in Ge/Ge0.8Si0.2 heterostructures), and Ge layers on insulator (GeOI).

The strong spin-orbit coupling in combination with the superconducting proximity effect will be exploited to reach topological superconductor states hosting Majorana-fermion edge quasi-particles.

This PhD is part of the DRF-Impulsion project SUPER-G and of the TOPONANO ANR project.

The student will take active part in device fabrication at the PTA cleanroom and low-temperature transport measurements in dedicated cryostats equipped with superconducting vector magnets.

  • Keywords : Mesoscopic physics, Solid state physics, surfaces and interfaces, INAC, PHELIQS
  • Laboratory : INAC / PHELIQS
  • CEA code : SL-DRF-19-0565
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Short wave Infra Red diffuse reflectance spectroscopy for noninvasive molecular detection medical devices

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Start date : 1 October 2019

offer n° SL-DRT-19-0562

Diabetes is a major public health and industrial issue, with the number of diabetics worldwide estimated at 415 million. Until recently, to control their blood glucose, patients had to prick their fingertips. To avoid this inconvenience, laboratories have recently been offering minimally invasive measurement systems that can be interrogated using a smartphone. This evolution, although major, still poses many problems, such as its cost, its size, or its invasiveness, even reduced. As such, a medical optical sensor, reliable, inexpensive would represent a major breakthrough: many players in microelectronics such Apple or Google produce an effort in this direction.

In vitro, the sugar measurement can be performed by diffuse spectroscopy in the SWIR domain (wavelength range 1 – 1.7 µm). A fraction of the photons produced by an immersed light source (emitter) diffuse into the liquid and emerge from it by the interplay of multiple reflections. The sugar absorption is on a band around 1.5 µm, the fraction of light emerging and detected in this range will be as lower as the sugar concentration is high. Multispectral analysis provides realistic concentration measurements. In vivo, the results are much worse because of the heterogeneity of the biological tissues and the presence of many interferents (other absorbents). The purpose of the thesis is to remove these biases by developing a new type of optical sensor comprising on the one hand several emitters, on the other hand a plurality of detectors.

This subject concerns a candidate who must have received a physicist training with a solid module dedicated to optics / photonics, interested in a work at the interface between physics and biology.

  • Keywords : Engineering science, Mathematics - Numerical analysis - Simulation, Optics - Laser optics - Applied optics, DTBS, Leti
  • Laboratory : DTBS / Leti
  • CEA code : SL-DRT-19-0562
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