We propose here cost-effective gate-first dual-metal/dual-high-k CMOS technology in which Fermi-level pinning is "positively" utilized to reduce threshold voltages for the first time. After systematic investigation on the relation between oxygen vacancies in Hf-based high-k film and electrical characteristics, we concluded that the Fermi-level pinning is unavoidable in principle with a thin EOT, but is a stable phenomenon that should be intentionally utilized. In our proposed method, source of oxygen interstitials (Al) is contained in metal gate material for p-FET, and consequently the flatband voltage is properly modulated by "opposite" Fermi-level pinning due to the oxygen interstitials incorporated into the underlying high-k film after high temperature annealing. It is also noteworthy that this method is simple and cost-effective because the initial high-k films are identical for n- and p-FET but they are automatically converted into dual high-k after the annealing process.
Cerebrolysin (FPF1070) is an extract from pig brain obtained after enzymic digestion, containing free amino acids (85%) and low-molecular weight amino acid sequences (15%). We studied FPF 1070 to determine its ability to protect against delayed neuronal death in the gerbil when administered before and after ischemia. Transient forebrain ischemia was produced by occluding both common carotid arteries. Morphological changes in the CA1 sector of the hippocampus were evaluated 4 days after 5 min. occlusion. The formation of hydroxyl radicals in the postischemic (15 min. occlusion) reperfused (2 min.) brain was measured with HPLC using salicylate (SA). SA reacts with hydroxyl radicals and yields 2,3- and 2,5-dihydroxybenzoic acid (2,3- and 2,5-DHBA), which can be detected by HPLC-ECD. Gerbils treated with FPF 1070 revealed significant protection of CA1 neurons when it was applied 2 hrs before the occlusion. In contrast, no clear beneficial effects were observed when FPF 1070 was administered immediately after the recirculation. Concentrations of 2,3- and 2,5-DHBA after reperfusion increased significantly compared to the basal levels both in the hippocampus and cerebral cortex. The 2,5-DHBA contents in the postischemic reperfused brain was significantly reduced when FPF 1070 was administered 2 hr. before the occlusion. The administration of dimethylsulfoxide (DMSO), a hydroxyl radical scavenger, prevented ischemia-reperfusion-induced delayed neuronal death, and significantly reduced the 2,5-DHBA content after reperfusion. The results indicated that hydroxyl radicals are produced in the postischemic-reperfused brain and that hydroxyl radical scavenging action of FPF 1070 played an important role in preventing delayed neuronal death.
We implanted B ions in a 110-nm-thick HfO/sub 2/ layer, subjected the substrates to various thermal processes, and evaluated the diffusion coefficient by comparing experimental and numerical data. We found that the diffusion coefficient of B in HfO/sub 2/ is higher than that in SiO/sub 2/ by about four orders and almost the same as that in Si. Therefore, the penetration of B through this layer can be expected to be significant, making the use of a cover layer indispensable for p/sup +/ polycrystalline silicon gate devices.
Hemoglobins (Hb) Yakima and Kempsey were purified from patients' blood with diethylaminoethyl cellulose column chromatography. The oxygen equilibrium curves of the two hemoglobins and the effects of organic phosphates on the function were investigated. In 0.1 M phosphate buffer, Hill's constants n for Hb Yakima and Hb Kempsey were 1.0 to 1.1 at the pH range for 6.5 to 8.0 and the oxygen affinities of both the mutant hemoglobins were about 15 to 20 times that of Hb A at pH 7.0. The Bohr effect was normal in Hb Yakima and one-fourth normal in Hb Kempsey. In the presence of inositol hexaphosphate, the oxygen affinities to Hb Yakima and Hb Kempsey were greatly decreased, and an interesting result revealed that these hemoglobins showed clear cooperativity in oxygen binding. Hill's constant n in the presence of inositol hexaphosphate was 1.9 for Hb Kempsey and 2.3 for Hb Yakima at pH 7.0. The cooperativities of these mutant hemoglobins were pH-dependent, and Hb Kempsey showed high cooperativity at low pH (n equal 2.1 at pH 6.6) and low cooperativity at high pH (n equal 1.0 at pH 8.0). Hb Yakima showed similar pH dependence in cooperativity. In the presence of inositol hexaphosphate, Hb A showed a pH-dependent cooperativity different from those of Hb Yakima and Hb Kempsey, namely, Hill's n was the highest in alkaline pH (n equal 3.0 at pH 8.0) and decreased at lower pH (n equal 1.5 at pH 6.5). 2,3Diphosphoglycerate bound with the deoxygenated Hb Yakima and Hb Kempsey, however, had no effect on the oxygen binding of these abnormal hemoglobin. The pH-dependent cooperativity of alpha1beta2 contact anomalous hemoglobin and normal hemoglobin was explained by the shifts in the equilibrium between the high and low ligand affinity forms.
Metal spinning is a plastic forming process for forming rotational shapes. In this process, a sheet metal blank attached to a rotating mandrel is subjected to a force by a roller tool and formed into a desired shape. This process is more suitable for high-mix low-volume production than press forming. Former studies on forming nonaxisymmetric shapes encountered the problem that the shapes were limited to noncylindrical shapes. In this study, we propose a synchronous multipath metal-spinning method for nonaxisymmetric shapes with vertical sidewalls. The tool trajectory changes from the flat shape of the blank gradually to fit the shape of the mandrel surface. Linear interpolation between the blank and mandrel shape along normalized planar paths, which constitute curved- and straight-path elements, is used to calculate the tool trajectory in three-dimensional space. The cross-section shape of the mandrel is measured by touching it with the roller using force control. It is possible to independently handle the mandrel shape, blank shape, and the paths for interpolation in this method. Cylindrical and rectangular box shapes are successfully formed from thin aluminum sheets in forming experiments.
We have fabricated 55-nm poly-Si gated n- and p-MOSFETs with HfO/sub 2/ gate dielectric of 3-nm physical thickness deposited by atomic layer deposition (ALD). A conventional CMOS process was used with high-temperature S/D anneal of /spl ges/1000/spl deg/C, cobalt-silicide and pocket implants. The devices showed very promising characteristics for low standby power applications due to drastic reduction of gate leakage current.
