(Invited) The Contribution of Thin Film Technologies to the Future Challenges of a Connected Society
Authors: Bonnaud Olivier 
Published: December 2020

This paper highlights the future challenges related to the exponential development of connected objects and the Internet of Things. These challenges concern the integration of components, circuits and systems, the density of elementary components, but also the heterogeneous assembly, the data flow in communications and the energy consumption of the whole connected system. Indeed, current technologies and the amount of data transmitted currently lead to an exponential growth in energy consumption at the global level, a growth that will no longer be realistic and acceptable from 2030 onwards. To counteract this, the entire chain of integrated functions that are physically realized by microelectronic components, circuits and systems needs to be revisited. The main challenges will therefore focus on reducing the consumption of electronic functions including sensors and actuators, signal conversion and processing devices, energy collection and storage devices, display panels and short- and long-distance communications systems, and power electronics as well. Among these points, it should be noted that the number of sensors is increasing significantly, with predictions indicating that the number of sensors in the world is expected to reach 10 trillion by 2030, which corresponds to about a thousand sensors per inhabitant. Moreover, a strategy will have to be adapted not to increase the flow of data transmitted over long distances to data centers and cloud storage (or equivalent), but rather to prefer the use of short-range communications, which are much less energy-intensive.

This evolution involves new technological approaches including very highly integrated components and circuits (ULSI or Ultra Large Scale Integration) but also thin film technologies based on inorganic and organic materials. These technologies are becoming a priority for the development of integrated sensors, energy production and storage systems and for the realization of transducers such as electrical generation of optical signals or contact-controlled flat panel displays. Three-dimensional heterogeneous structures combining the stacking of highly integrated devices with the superposition of thin film devices are also promising for data storage, which is becoming one of the major elements of databases and data centers.

Depending on the desired properties, the solutions are more based on the modification of the materials constituting the basic electronic components in order to minimize the currents in the off-state but also the on-state, on the architectures of the circuits which must limit the consumption at stand-by, on the stacking of the layers constituting the devices and finally on the heterogeneous assembly involving several technologies. This will also require adapting the skills and know-how of technicians, engineers, doctors and researchers in order to overcome the technological challenges.

This paper will thus successively focus on a general presentation of the challenges related to the development of connected objects and the Internet of Things, which involve all the main functions of electronics, which have consequences on all societal domains since the vast majority of applications in rapid development use electronic components and systems. Particular attention will be paid to the energy consumption of components and circuits that induce an exponential consumption of connected objects and the Internet. The next part will focus on the different approaches envisaged and more particularly on thin-film devices. In order to complete the picture, the last part will focus on the human needs in skills and know-how by giving as an example the strategy of the French microelectronics training network carried out over the last ten years. The final objective is to take up the technological and human challenges within the framework of the French electronics sector, set up in 2019 by the French government, which aims at making a significant contribution at the international level in the development of the digital society involving the Internet of Things, artificial intelligence and industry 4.0.