Reference : UMR7252-STEBIL-004
Workplace : LIMOGES
Date of publication : Wednesday, September 21, 2022
Scientific Responsible name : Stéphane Bila (XLIM, Limoges, France) and Philippe Coquet (CINTRA, Singapore)
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 December 2022
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
FUSION - 3D integration of functionalized sub-mm-wave interposers using vertically aligned carbon nanotubes
Future generations of information technology (IT) systems will have to use higher frequency bands to meet the ever-increasing demand in terms of throughput and mass of data to be exchanged. Higher frequencies mean smaller wavelengths, and therefore very compact dimensions of electronic components and circuits, so that their realization with conventional manufacturing technologies becomes problematic, the levels of resolution required at a few hundred GHz no longer tenable.
The exploitation of new technologies based on nanomaterials, such as carbon nanotubes (CNT), is a solution envisaged to integrate devices at sub-millimeter and THz frequencies by reaching sufficiently fine resolutions.
XLIM and CINTRA have been collaborating for 10 years on the design and integration of submillimeter components and circuits using CNT-based technologies. The collaboration, which has given rise to numerous publications and two patents, is based on the complementarity of the two units, XLIM contributing its skills in terms of multiphysics modeling, design and characterization of very high frequency devices and CINTRA, its skills in terms of fabrication, transfer and integration of CNTs on different substrates for their implementation.
The various joint works have made it possible to develop and test the technology of vertically aligned CNTs for the encapsulation of components, the interconnection and the realization of basic functions (waveguides) at frequencies beyond 100 GHz, in particular within the framework of the ANR TRICOT project which has just ended. In particular, we have developed a low-temperature CNT transfer technology which makes it possible to produce 3D structures aimed at replacing metallic structures in passives, the production of which, in terms of precision and cost, becomes complex at high frequencies.
To continue this work, we wish, within the framework of this thesis, on the one hand to support the optimization of the technology of manufacture and transfer of the vertically aligned CNTs, and on the other hand, to implement, at a few hundred GHz, new functions such as filters and couplers, for the production of functionalized interposers using this technology.
This work should be carried out in close collaboration between the 2 units to ensure control of:
• Integration of vertically aligned CNTs with controlled density and reduced contact resistances,
• The modeling of CNTs integrating the parameters of the technology for precise consideration of all physical phenomena in the design of devices,
• The optimized design of the functions taking into account the precise models for the CNTs integrated into the structure
• The characterization of basic demonstrators or performing advanced functions such as filters, couplers or distributors with a view to the production of functionalized interposers to evaluate the performance of very high frequency technology
The PhD student will be posted to XLIM, in Limoges, France, to carry out the computer-aided design and characterization of components and circuits. He or she will be required to make several stays in Singapore to understand the manufacturing and transfer technologies of CNTs and to propose relevant and compatible demonstrators with these technologies.
Constraints and risks
Several missions to Singapore will be scheduled during the thesis
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