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(Zr0.52
(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.
Scientific Reports, 2016
(a) and Seeded Photosensitive (b) solution systems. X-ray diffractograms of the films annealed at 600°C are included. A scheme showing the respective crystallization mechanisms proposed for each system at different stages (i: photoactivated gel film; ii: amorphous oxide film; iii: crystalline PZT film) is depicted.