Research Projects

High entropy oxides (HEOs) are an exciting family of functional materials with tunable dielectric and ferroelectric behavior through compositional configurational disorder. Their capacity for stabilizing multiple cations within a single-phase structure provides unprecedented opportunities for the creation of advanced material systems for future-generation electronics [1-4]. At the same time, the international drive for ultralow-power and energy-efficient computing creates the need for new transistor innovations, most notably methodologies that allow sub-1 V operation. Recent progress in negative capacitance field-effect transistors (NCFETs) has revealed that the incorporation of ferroelectric/dielectric bilayers as passive stacks can dramatically reduce the switching voltage by stabilizing the negative capacitance effect. Although doped-hafnia-based ferroelectrics have been picked up, their long-term stability and integration issues require investigation of other material systems. In this regard, the current research intends to develop and integrate HEO-based ferroelectric and dielectric thin films in order to achieve steep-switching, ultralow-power NCFETs. This work will concentrate on the fabrication and synthesis of high dielectric constant multicomponent HEOs with stable ferroelectricity, produced through scalable chemical solution deposition directly on silicon. The layers will be engineered for electrical reliability, phase purity, and interface quality. The stacks of ferroelectric/dielectric based on HEOs will be incorporated into the gate architecture of p-type NCFETs with a goal of sub-1 V operation and high energy efficiency. In addition, a set of these devices will be rigorously tested under a systematic approach to achieve minimal variation in their performance, striving for reliability and consistency. This research has the potential to drive forward ultralow-power electronics with the incorporation of HEO ferroelectrics and dielectrics, enabling the development of integrated circuits with ultralow input voltages. The results are likely to significantly improve commercially scalable complementary metal-oxide technology for multifunctional applications and driving advancements in the next-generation energy-efficient electronics. 1. Rost, C. M., Sachet, E., Borman, T., Moballegh, A., Dickey, E. C., Hou, D., Jones, J. L., Curtarolo, S., and Maria, J. P. (2015). “Entropy-stabilized oxides.” Nat. Commun., 6(1), 8485. 2. Sarkar, A., Breitung, B., and Hahn, H. (2020). “High entropy oxides: The role of entropy, enthalpy and synergy.” Scr. Mater., 187, 43–48. 3. Bérardan, D., Franger, S., Dragoe, D., Meena, A. K., and Dragoe, N. (2016). “Colossal dielectric constant in high entropy oxides.” Phys. Status Solidi - Rapid Res. Lett., 10(4), 328–333. 4. Salian, A., and Mandal, S. (2022). “Entropy stabilized multicomponent oxides with diverse functionality–a review.” Crit. Rev. Solid State Mater. Sci., 47(2), 142–193.