(Invited) Progressive Involvement of Thin Film Technologies in Connected Objects to Meet New Societal Challenges
Authors: Bonnaud Olivier 
Published: November 2022

This presentation is part of a context of galloping evolution of digitalization of all societal areas. These concern the administrative and financial management of economic activities, the management of the production of all kinds of objects and systems in an industry 4.0 vision, or the control of the functioning of communication, transport, health, energy or security equipment, mainly.

This invasion of digital systems and communication may appear as a progress in many societal applications, but this unprecedented development creates new limitations that must be quickly overcome. If from the users' point of view, the implemented technologies appear more and more simple thanks to their software, ergonomic and user-friendly aspects, the physical support of digital objects constitutes the foundation of all these sophisticated tools. It can be noted that the great majority of user-friendly devices in direct link with the users employ flat panel displays and many other microsystems. Any evolution or improvement of these “Physical Cyber Systems” tools is based on the innovation of microelectronic circuits and systems whether they are integrated, large area or hybrid.

Limitations appear in different forms, whether they are of a scientific, technical and technological origin, or also of a human origin, particularly with regard to the nature and the pool of skills, know-how, and innovation capabilities.

This talk highlights the future challenges related to the exponential development of connected objects, sensors, the Internet of Things and the exploitation of transmitted and stored data. Indeed, globally, the total number of sensors and actuators grows by a factor of 2 in less than 2 years, the number of connected objects by a factor of 2 every 4 years, and the number of bytes transferred annually by a factor of 2 every 2 years, having reached the Zettabytes in 2018 and expected to reach the Yottabytes in 2030 (1024). Knowing that in a complete chain of data transfer about 50% of the equivalent consumption is spent by data centers, 30% by transmissions at all levels and 20% by industrial, professional or individual users, the effective power consumption is also growing exponentially, in practice by a factor of 2 every 4 years, despite the current permanent improvement of microelectronic technologies. In 2030, the world electricity consumption due to digital technologies should reach the world electricity consumption of 2018, i.e. about 27,000 TWh without any major intervention on the hardware level! It is necessary to review the entire chain of integrated functions that are physically realized on the basis of microelectronic components, circuits and systems. It is therefore the field of microelectronics that will have to bring innovation to face the challenges.

At the level of microelectronics, the fields of intervention will therefore be multiple. The first area concerns the elementary components, which must be even more integrated but which must above all consume less. For example, major efforts are currently being made on memories that could consume up to 1000 times less than silicon-based memories thanks to the use of thin metal and insulator films. The stacking of integrated components using thin-film processes also provides solutions for integration and low consumption. The second area aims at a more intensive use of hybrid technologies in sensors and actuators involving thin films and multidisciplinary approaches. The third area is related to the reduction of energy consumption by modifying circuit architectures, by controlling the switch-off of inactive functions (a ratio of 1000 is expected), by using new materials such as organics for displays, or by involving large-gap semiconductors for high-power devices allowing to significantly reduce their leakage currents and their on-resistances. The fourth area is more complex and concerns the reduction of the use of rare elements in technologies that very often involve very high consumption in connection with their extraction, purification and transport. Their use in very thin layers such as those transferred onto insulating substrates in SOI technologies could be a solution. The last area concerns the human factor. The level of knowledge and know-how must be increasingly high with more and more players. Currently, many companies worldwide complain about the lack of candidates for job offers and point out the jobs in shortage. The challenge in this case is transferred to the international scientific and educational community.

After presenting the different challenges in this context, this talk highlights the different approaches to meet the challenges, emphasizing the potential interest of thin film technologies. It concludes with the human challenge, which is becoming a key point for the success of the digital extension at the global level.