Effect of annealing and hydrogen on properties of electrodeposited platinum electrode and lead-zirconate-titanate films for ferroelectric random access memory applications

The selection of capacitor electrode materials for the nonvolatile ferroelectric random access memory is one of the most important issues because capacitor electrical characteristics are strongly influenced by the electrode materials. The lower Pt electrode was electrodeposited on the Ti seed/Pt seed layer. Two different thicknesses of Ti seed layer (5 and 15 nm) were adopted, and lead-zirconate-titanate (PZT) was deposited on the electrodeposited Pt. The Pt crystal orientation with a 5 nm Ti seed layer is much better than that with a 15 nm Ti seed layer, and the deposited PZT shows much better crystal orientation. Due to better crystal orientation of the PZT layer in the case of a 5 nm Ti seed layer, a Pt/PZT/Pt capacitor well-saturated D-V hysteresis loop was obtained whereas little current was observed in the large electric field. With the 15 nm Ti seed layer, numerous several-mu m-sized voids formed on the lower Pt electrode surface. With the 5 nm Ti seed layer, fewer voids formed on the lower Pt electrode surface. Glow discharge spectrometry measurement with a 15 nm Ti seed layer shows much higher H intensity than that with a 5 nm Ti seed layer, and the H peak coincides with the Ti peak. The H existing in the Ti seed layer must have transmitted into the PZT layer and deteriorated the PZT crystal orientation. (c) 2005 The Electrochemical Society. </p

Saposin B Is a Human Coenzyme Q10-Binding/Transfer Protein

Coenzyme Q10 (CoQ10) is essential for ATP production in the mitochondria, and is an important antioxidant in every biomembrane and lipoprotein. Due to its hydrophobicity, a binding and transfer protein for CoQ10 is plausible, but none have yet been isolated and characterized. Here we purified a CoQ10-binding protein from human urine and identified it to be saposin B, a housekeeping protein necessary for sphingolipid hydrolysis in lysosomes. We confirmed that cellular saposin B binds CoQ10 in human sperm and the hepatoma cell line HepG2 by using saposin B monoclonal antibody. The molar ratios of CoQ10 to saposin B were estimated to be 0.22 in urine, 0.003 in HepG2, and 0.12 in sperm. We then confirmed that aqueous saposin B extracts CoQ10 from hexane to form a saposin B-CoQ10 complex. Lipid binding affinity to saposin B decreased in the following order: CoQ10>CoQ9>CoQ7>>α-tocopherol>>cholesterol (no binding). The CoQ10-binding affinity to saposin B increased with pH, with maximal binding seen at pH 7.4. On the other hand, the CoQ10-donating activity of the saposin B-CoQ10 complex to erythrocyte ghost membranes increased with decreasing pH. These results suggest that saposin B binds and transports CoQ10 in human cells