Active layers of high-performance lead zirconate titanate at temperatures compatible with silicon nano- and microelectronic devices

Abstract

Applications of ferroelectric materials in modern microelectronics will be greatly encouraged if the thermal incompatibility between inorganic ferroelectrics and semiconductor devices is overcome. Here, solution-processable layers of the most commercial ferroelectric compound ─ morphotrophic phase boundary lead zirconate titanate, namely Pb(Zr0.52Ti0.48)O3 (PZT) ─ are grown on silicon substrates at temperatures well below the standard CMOS process of semiconductor technology. The method, potentially transferable to a broader range of Zr:Ti ratios, is based on the addition of crystalline nanoseeds to photosensitive solutions of PZT resulting in perovskite crystallization from only 350 °C after the enhanced decomposition of metal precursors in the films by UV irradiation. A remanent polarization of 10.0 μC cm−2 is obtained for these films that is in the order of the switching charge densities demanded for FeRAM devices. Also, a dielectric constant of ~90 is measured at zero voltage which exceeds that of current single-oxide candidates for capacitance applications. The multifunctionality of the films is additionally demonstrated by their pyroelectric and piezoelectric performance. The potential integration of PZT layers at such low fabrication temperatures may redefine the concept design of classical microelectronic devices, besides allowing inorganic ferroelectrics to enter the scene of the emerging large-area, flexible electronics.

Influence of Crystallization Temperature on Structural, Ferroelectric, and Ferromagnetic Properties of Lead-Free Bi0.5(Na0.8K0.2)0.5TiO3 Multiferroic Films

“…Habouti et al produced the evidence of an interfacial intermetallic layer between Pt and Pb when PZT thin films were annealed at 500°C [27]. By using XPS technique, Bretos et al [28,29] also showed the existence of a transient intermetallic Pt x Pb between PZT and Pt and determined its composition and thickness in films. e intermetallic layer plays the role as a dead layer causing a weak crystallinity in the films.…”

Photochemical solution processing of films of metastable phases for flexible devices: the β-Bi2O3 polymorph

“…Special attention has been paid to chemical solution deposition (CSD), because it offers benefits such as low cost, compositional control, large-area deposition or high-throughput fabrication. Additionally, CSD provides a particular advantage; the tailoring of the solution chemistry to achieve special processing targets (e.g., to reduce the high temperatures conventionally used, over 600 °C)123456. Recent developments in the preparation of metal oxide thin films by solution methods have made use of a specifically design of homo- and hetero-metallic molecular complexes aimed either at the reproduction of a molecular structure similar to that of the crystal structure of the oxide phase to be synthesized in the film, or at the increase of their photosensitivity for irradiation purposes27891011.…”

“…Within the framework of the CSD methodology, sensitive metal coordination complexes have shown a huge potential for the processing of oxide thin films at low temperatures (<400 °C), like several Pb- and Bi-based ferroelectric perovskites1011. These compounds are characterized by reactive metal – to – ligand charge transfer states, where a shift of the electronic distribution can be induced by UV light, resulting in the dissociation of the complex bonds and the formation of the metal – O – metal skeleton of the oxide material236101112. As a result, photochemistry has become a powerful tool for the fabrication of films of crystalline oxides at low temperatures, minimizing the high energy consume of the traditional thermal annealing methods and providing a new pathway to integrate functional oxide layers with flexible polymers212.…”

Lead Zirconium Titanate Films and Devices Made by a Low- Temperature Solution-Based Process

“…As a result, ferroelectric perovskite structure can be obtained at 400°C. Furthermore, incorporation of nanoseeds into the Ph sol (PhS) increased Ferroelectrics and Their Applications the number of nucleation sites in the resulting film, which produced a further reduction of crystallization temperature [34]. The mechanism proposed for the low-temperature processing of PhS-PZT thin films is described in Figure 7.…”

“…This technique uses focused high-energy laser beam in continuous or pulse mode Lead Zirconium Titanate Films and Devices Made by a Low-Temperature Solution-Based Process http://dx.doi.org/10.5772/intechopen.79378 Figure 7. Mechanisms for the low-temperature processing of inorganic ferroelectric thin films using the activated PhS solutions [34].…”