6. Conclusions

Ultra-high permittivity dielectrics are currently a key technology from a strategic point of view. Whether we're talking about replacing lead-containing dielectrics, the manufacture of which runs counter to new European environmental laws, reducing the size of field-effect transistors, integrating capacitors into printed circuit substrates, or creating multilayer systems with very high capacitances, the stakes for increasing performance are very high. This is why new approaches, based not only on the chemical constitution of materials but also on their nano- and microscopic structure, are increasingly being employed.

In this article, we have discussed the main classes of materials capable of meeting these needs: classical ferroelectric ceramics and relaxers, as well as their solid solutions, often used because of their morphotropic phase boundary, and also ceramic-based...