Integration of Ferroelectric Random Access Memory Devices with Ir/IrO₂/Pb(Zr_xTi_1-x)\barO₃/Ir Capacitors Formed by Metalorganic Chemical Vapor Deposition-Grown Pb(Zr_xTi_1-x)O₃

Abstract

Metal organic chemical vapor deposition (MOCVD) of Pb(Zr x Ti 1−x )O 3 (PZT) and its capacitor module process were established for ferroelectric memory device integration. The 130 nm-thick PZT films were deposited on Ir layers at 530 • C or 550 • C. The remnant polarization of the Ir/IrO 2 /PZT/Ir capacitors is in the range of 15 to 21 µC/cm 2 , and their leakage current is 10 −5 A/cm 2 at 2.5 V without additional annealing. The degradation in their switching endurance is less than 5% after 10 10 cycles, indicating that the interfaces formed between the PZT and Ir layers can be optimized to improve their fatigue properties. To evaluate the capacitors on the devices, the conventional backend process was performed after encapsulating the capacitors with AlO x /TiO x layers located on the poly-Si plug. High charge separation and fully functional bit activities were obtained, demonstrating that this MOCVD-PZT process is a reliable integration scheme for high-density ferroelectric memory devices.

Modulating Ferroelectric Response in Colloidal Semiconductor Nanocrystals through Cation Exchange

“…Ferroelectrics are a class of materials that exhibit unique electronic behavior that has the potential to revolutionize energy storage and random-access memory design. − Additional energy-harvesting applications arise as a result of their polar, non-centrosymmetric crystal structure, causing these materials to exhibit both piezoelectric and pyroelectric properties imparting capacitance and room temperature polarizability. − Bulk barium titanate is a classic ferroelectric material that has been prepared by glycothermal and hydrothermal syntheses and has been utilized in capacitors and data-storage devices. , However, the ability to produce nanosized ferroelectric materials is highly desirable in order to achieve a greater density of independent ferroelectric domains. Nanoscale BaTiO 3 has been synthesized by glycothermal treatment, which showed a dependence of ferroelectric response on size.…”

Fluorescent Colloidal Ferroelectric Nanocrystals

“…Introducing ferroelectric properties in quantum dots (QDs) through cation exchange multiplies their already ever-growing list of applications, elevating their utility in industry. CdSe nanocrystals are ubiquitous in nanoscience and have been developed for applications in lighting, displays, biology, solar cells, solar concentrators, and lasers. − However, the ability to change the polarization of ferroelectric materials through electric, thermal, and mechanical energy allows for the additional use of these nanoparticles in ferroelectric random access memory (FRAM) and as energy harvesters, energy scavengers, actuators, transducers, capacitors, and microelectromechanical (MEMS) devices. − …”