Caractérisation de la qualité des matériaux et interfaces à base de semiconducteurs par génération de seconde harmonique (SHG)

Publié le : 19 avril 2018

Delai limite pour l’application: 1er JUIN 2018

  Debut du Contrat : 1er OCTOBRE  2018

IMEP – LAHC, MINATEC – INPG, 3, Parvis Louis Néel, 38016, Grenoble
Irina Ionica (Associate Professor Grenoble ING)
Guy Vitrant (CNRS researcher)

Irina Ionica,, 04 56 52 95 23
Guy Vitrant,

This PhD topic is in the context of research on novel characterization methods of ultra-thin films and interface quality for applications in micro, nanoelectronics, photovoltaics, photonics, etc. In this context, a key element today is to propose and develop innovative characterization methods that do not need any physical contact, therefore avoiding any damage of the advanced ultra-thin substrates. A very promising technique was recently proposed: the second harmonic generation (SHG)1. The intensity emitted by centrosymmetric materials at the double incident laser frequency is related to the electric field present at the interfaces, and consequently to the charges, interface states etc.
The PhD student will benefit from innovative equipment, unique prototype in Europe, installed at IMEP-LAHC in 2014. Additionally, we developed a home-made optical simulator in order to explain the experimental results.

PhD objectives and work-to-do:
       – The first objective of this multidisciplinary PhD is to  is to calibrate the SHG in order to identify specific signatures of the chemical and the electrostatic passivation in high-k dielectric stacks used in image sensors and photovoltaic cells. The SHG results will be correlated with electrical parameters from measurements on simple test structures (i.e. MOS capacitors) fabricated in the clean-room.
– The second objective will consist in qualifying the measurement tool, using standard silicon-on-insulator (SOI) wafers. The calibration will be done based on benchmark studies using as comparative elements other well-known measurement techniques, such as the pseudo-MOSFET technique (intensively used today for electrical characterization of SOI, but invasive and destructive). This phase will lead to the validation and the extension of models for SHG, for the extraction of material quality parameters such as the density of interface states, in a completely contactless way.
For both cases, one on the challenges will be to de-correlate the optical effects from the electrical properties of the interface. Our home-made simulator will be continuously adapted in order to model the optical response of the structures under study and to isolate only the electrical part from the SHG measurements.

The topic is strongly connected to both academic and industrial world, since it covers the physical understanding (nonlinear optics, electrical semiconductor properties, electrical coupling in thin SOI) and the pragmatic applications for microelectronics. The eventual tool developments will be done in collaboration with
the American start-up company FemtoMetrix who installed the equipment. The SOI studies will benefit from our long-lasting collaboration of our laboratories with SOITEC, giving access to high quality state-of-the-art wafers. The passivation schemes studies will be developed in collaboration with our partner INL (Institut des Nanotechnologies de Lyon). The student could also benefit from samples of high interest to the imaging sensors, from ST Microelectronics.

Knowledge and skills required:
This Ph.D. topic belongs to the micro-nano-electronics filed but it is multidisciplinary (non-linear-optics, electrical characterization and modeling of semiconductor-dielectric interfaces). The candidate must have a solid knowledge of solid-state physics, physics of semiconductors and nonlinear optics.
The candidate is expected to enjoy both experimental and simulation work. Scientific curiosity, motivation, creativity are mandatory qualities in order to take full advantage of the scientific environment of this thesis and to gain excellent expertise for his/her future career. The topic is close to both fundamental physics, as well as industrial world; after the Ph.D. the candidate will easily adapt to both academic and industrial research environments.
The candidate must have a very good academic record, with high grades.

1 M.L. Alles et al, IEEE Transactions on Semiconductor Manufacturing, vol. 20, 107 (2007) D. Damianos et al, Solid State Electronics, vol. 115, p.237, 2016

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