31 research outputs found
Active layers of high-performance lead zirconate titanate at temperatures compatible with silicon nano- and microelecronic devices
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
Thermal Stability of Hf-Based Gate Dielectric Stacks with Rare-Earth Oxide Capping Layers
Universality of charge transport across disordered nanometer-thick oxide films
heoretical and experimental analysis of electron transport across ultrathin, homogeneously disordered oxide layers is presented with particular regard to the question of how much the effects are universal. We show that (i) distribution of transparencies across dirty subnanometer-thick insulating films is bimodal and (ii) conductance-voltage characteristics of oxide layers with thicknesses increased up to several nanometers are power functions with an index near 1.3. The universality of transport properties is explained as an effect of strong local barrier-height fluctuations generated by the presence of oxygen vacancie