Enhancing Voltage Amplification in FE-DE Heterostructure with Multiple Dielectrics

This paper presents how the application of different dielectrics affects the ferroelectric-dielectric (FE-DE) heterostructure's properties, including voltage amplification, capacitance increase, and negative capacitance stability. The initial study examines an isolated ferroelectric capacitor and found an S-shaped voltage-charge relationship. In ferroelectrics, negative capacitance is indicated by the negative slope in charge against voltage characteristics, instability is observed. An additional dielectric capacitor is added in series to stabilize negative capacitance. In a non-leaky heterostructure using Silicon dioxide (SiO2), Silicon nitride (Si₃N₄), Aluminum oxide (Al₂O₃), and Hafnium silicate (HfSiO₄) as dielectrics and Lanthanum (La) as the ferroelectric material, when the capacitance of dielectric material is less than the negative of the inverse anisotropy constant, stability is achieved. The charge against voltage characteristics does not exhibit any negative slope regions which ensures positive capacitance in the heterostructure. Ferroelectric and dielectric capacitors are used in series to lower the total energy and stabilize the state of negative capacitance. Voltage amplification results from this, confirming the heterostructure's effectiveness in enhancing voltage with small modifications to the supply. Greater capacitance values of the dielectric can result in stronger voltage amplification.