NEGCAP

The negative capacitance (NC) effect has been presented as a possible solution to the necessary reduction of the switching voltage in field effect transistors and could thus contribute to the future development of low power switching devices. The work that we plan to carry out is mainly positioned in the development of mature static NC structures. This maturity will be reached if we can control and stabilize the physical phenomenon at the origin of this NC. To succeed, it will be necessary to develop heterostructures alternating layers of a few nanometers thick made of ferroelectric (FE) materials on the one hand and paraelectric (PA) materials on the other hand, and to control the quality of the interfaces essential to the stabilization of the NC effect. The choice of materials, the control of epitaxial stresses and electrostatic effects will be crucial to bring the NC phenomenon back to near-ambient temperature ranges. The consortium set up for this project intends to take up this challenge and for that it gathers competences and strengths in the elaboration of heterostructures, the fine characterization at the elementary scale of the materials, of their interfaces, of the structure in ferroelectric domains, the electrical characterization of these structures at the local and macroscopic scale in wide frequency and temperature ranges, clean room technologies for the realization of specific test vehicles. In this context, the objectives of the NEGCAP project are: (i) to fabricate model FE/PA structures in superlattice (for direct measurement of negative capacitance) and multilayer (for indirect measurement of NC), (ii) to determine and model the dielectric response of these structures in a wide frequency range, (iii) to probe the properties at the FE/PA interfaces in order to understand the physical phenomena involved, (iv) to identify the fields of application of these structures and to propose "negative capacitance effect at room temperature" structures.