This study examines the effects of bottom electrodes for metal ferroelectric metal (MFM) capacitor applications. We investigated the following parameters of bottom electrodes and Pb(Zr0.53Ti0.47)O3 (PZT) thin films: substrate temperature, rf power, gas flow rate, Ar/O2 ratio, electrode material, and post-annealing effect. Bottom electrodes grown at 300°C for Pt and 200°C for RuO2 exhibited a film resistivity of 10-4 Ω·cm, had a surface roughness of approximately 55 Å and a preferred crystal orientation. Rapid thermal annealing (RTA) treatments on a Pt electrode at 600°C for 30 s improved the resistivity to 5×10-6 Ω·cm and generated the (111) preferred crystal orientation. PZT films exhibited a strong PZT (101) peak for an optimized Pt bottom electrode and (111), (200), (112) planes without preferred PZT orientations for the RuO2 electrode. A well-fabricated Pd/PZT/Pt capacitor showed a leakage current density in the order of 6×10-5 A/cm2, a dielectric constant (ε r) of 365, a remanent polarization (P r) of 27 µC/cm2, and a coercive field (E c) of 50.5 kV/cm. This paper discusses the bottom electrode properties as well as their recommended conditions in memory device applications of thin-film PZT capacitors.

This study aimed to evaluate the soundness of solid-state welded steels. STS 430F alloy with a rod type was selected as experimental material, and the friction welding was conducted at a rotation speed of 2,000 RPM and upset length of 3 mm. The application of friction welding on STS 430F rods led to significant grain refinement in the welded zone (1.3 µm) compared to that observed in the base material (16.8 µm). The refined grains in the welds contributed to the development of the mechanical properties. In particular, the Vickers microhardness was increased by approximately 25% compared to the base material, and the fracture at the tensile specimen of the welds occurred at the base material zone and not in the welded zone, which suggests a soundly welded state on the STS 430F rods.