The steady improvement of the microelectronic technology over the years was historically based on the miniaturization of semiconductor devices. To date, device dimensions are approaching some fundamental limits of materials and manufacturing processes. Therefore, a strong need is felt to investigate new materials, and/or innovative device architectures, allowing further technological progress. The aim is that of ensuring less power consumption and, possibly, improved performance. In this context, we are pursuing three different research lines.
- The first research line addresses the investigation of physical effects which are getting more and more important for the prediction of device performance, such as the quantum confinement of charge carriers in nanometric structures, band-to-band and source-to-drain electron tunneling, and quasi-ballistic transport, which makes classical transport models obsolete. In addition, this activity pursues the implementation of such models in home-made simulation tools. Commercial software tools are now widely used for device optimization within industrial environments. Yet, adequate physical models of strategic importance are still missing in commercial simulation tools.
- The next research line is pursuing the investigation of special devices characterized by a steep subthreshold swing. This property is required to make it possible lowering the supply voltage of integrated circuits with no performance penalty. In standard transistors the inverse subthreshold swing is limited by the Boltzmann distribution of high-energy electrons and cannot be reduced below 60 mV/dec. In order to break such limit it is required to filter out high-energy electrons entering the device active region. This filtering effect can be pursued by various techniques such as band-to-band tunnel field-effect transistors (TFETs), superlattice-based FETs and by exploiting the special band structure of 2D materials, such as graphene in so-called Dirac-source FETs. This activity is currently being pursued within a European project.
- Investigations carried out in the last decades have opened the way to the application of quantum mechanics to the information theory. The aim of this research line is to demonstrate the feasibility of a solid-state physical system able to pursue reversible, rather than dissipative, computation processes. The exploitation of quantum properties and, more specifically, the superposition of quantum states and the entanglement, made it possible to develop quantum computing systems which allow to overcome the classical limits for the solution of n-p complete problems. A project along these lines has been formulated and submitted to the European Commission. Algorithmic studies have demonstrated the potential of a hypothetical quantum computer to outperform classical systems for the solution of n-p complete problems, with a polynomial, rather than exponential, computation time against problem complexity.
