Test laser beam of integrated circuits and electronic systems

Presentation of the nanoelectronics research activities of the Laser team

The transition from the single-point sensor to source and detector arrays is one of the key elements of the terahertz wave roadmap. This transition is underway for CMOS systems below 500 GHz (Nearsense project), but the challenge remains unresolved for systems very broad pulse band (from 0.1 to 5 THz band). This key element is in collaboration with Mona Jarrahi from UCLA

Another important axis is the photonics-based THz source design and fabrication. The THz devices, i.e source, detector and other systems, are mostly developed from different approaches by using nonlinear optical processes in various materials (bulk crystal or gas), photoconductive antennas, or by tailoring the properties of the incoming laser (wavelength, duration, repetition rate…). The research work is undertaken from the simulations to the experiment in order to reach proofs of concept in the laboratory. The objectives are to improve system performances such as the efficiency, the spectral bandwidth toward the far infrared or to tailor the spatial profile with antenna networks. Thus, we also investigate several type of waveguide to confine THz radiation toward the application (e.g with fiber ) or to generate/detect efficiently the THz field (fibre, ridged waveguide…).

The increase in frequency will require in the future to have all the passive components as they exist in optics and microwaves, so as to design THz systems. Some may be an extension of existing concepts on other bands of the electromagnetic spectrum, with all the challenges of scaling, while other functions require the creation of new objects. Two short-term examples are, first, the development of terahertz waveguides, with two parts, one aimed at making waveguide-based sensors and the other related to infrared waveguides and the possibilities IR-THz coupling. A second example concerns the Luneberg THz antennas, which opens up prospects for increasing frequency and opening up applications to 6G and detection with radars.

While the volume of data is several gigabytes for a THz image, and data fusion and matrix sensors bring even larger volumes of data, one issue concerns the link between terahertz and digital science. Whatever the application, for NDT or telecom, the deployment of dedicated digital tools, and at different scales, will be essential. After years of work around tomography or holography, which were hitherto limited by existing technologies, computational imaging, in the broad sense, will experience a resurgence of interest with the integration of matrix systems.

Work is thus planned within the framework of the ANR Hypster (P. Mounaix) and also with A. Özcan from UCLA. Other integrations, both hardware and software, aim to perform data fusion, in particular for the millimeter band with FMCW radars, with calculations and AI as close as possible to the sensors, with ultimately a reduction post-processing operation (Terascope Project). This computational approach during acquisition, currently limited to time-frequency conversions and filtering, could in the future concern multi-sensor data fusion, SAR reconstructions, parameter extraction, identification in augmented reality, and so on. promote a rise in TRL for terahertz solutions (Collaboration Fraunhoper, Lytid, Optikan, UCLA, IOGS etc).

The contribution of terahertz on the societal level being one of the recognized strengths of our team. A first challenge will be to revisit certain applications in the light of the new possibilities offered by the terahertz technological breakthroughs.

Another important activity of the team is to create and use optical analysis techniques, laser and terahertz, for the diagnosis of microelectronic objects. Among the techniques we find three specific fields of application: Analysis of sensitivity to radiation effects, fault detection and fault injection. The analysis of sensitivity to radiation effects is treated by simulating the effect of a direct ionizing particle (space heavy ions, protons atmospheric) or indirect (atmospheric neutrons) by replacing the particle by an ultrashort laser pulse. The advantage of laser is that you can precisely locate in the space (micrometer resolution) and time (picosecond resolution) the ionizing effect. It is therefore possible to identify sensitive areas to allow the hardening of components or systems to sensitive application (aerospace, ground transportation, ….). Each sensitive area can be defined by volume and over a time window of operation. The detection of faults within the integrated circuit failure analysis. Optical techniques (photon emission) laser (OBIC, OBIRCH LVP, ltem) and terahertz (EOPTR) allow the use of different types of interaction with the system for accurate detection of a defect (crack, amorphization of the semiconductor, short-circuit, open circuit

The fault injection the evaluation of the robustness of the secure circuits. This injection can be done by sending a laser beam at different points of the chip or a terahertz wave broad spectrum of the component. The different techniques used are types of ‘pump’ (disruption of the functioning of the circuit by creating free charges), “probe” (analysis of the laser beam after passing through the substrate and reflection on the different interfaces, without disturbing the operation of the circuit ) and “pump-probe” (induction of a disturbance laser and analyzing the consequences of this disturbance by laser or terahertz wave).

Laser teams skills

Time Domain Spectroscopy: development and analysis

Implementation and design

Manipulation of optical pulse and THz radiation

Time domain analysis techniques

Design and development of sources and detector

Nonlinear photonics for THz radiation

Simulations: home-build code, HFSS, CST

Spectroscopy and imaging

Partners

Collaborations and partners

For the various research projects underway, the IMS Bordeaux laboratory and its teams rely on strong partnerships and collaborations, which allow for the creation of a synergy of strengths and a sharing of technical and human resources