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[en] Purpose: To evaluate performance characteristics of currently available superficial femoral artery (SFA) stents and stent delivery systems (SDS). Materials and Methods: Six 7 mm/80 mm stent systems were included: BIOTRONIK Astron Pulsar (4F), EDWARDS LifeStent Flexstar, ev3 PROTEGE Everflex, CORDIS Smart Control, BARD E-Luminexx, GUIDANT Absolute (all 6F). The SDS were evaluated for profile, flexibility in the stent region, trackability and pushability through a tortuous vessel model and release force during deployment. The stents were evaluated for flexibility, radial force during expansion and compression, and shortening. Results: The 4F system had a profile of 1.45 mm, and the 6F stent systems had a profile of 1.96 - 2.10 mm. The Astron Pulsar was most flexible (195 Nmm2) compared to 334 - 972 Nmm2 for the 6F systems. The track force of the stiffest system (Flexstar, 0.314N) was higher than that of the Astron Pulsar (0.273N) but lower than that of the other systems (0.387 - 0.579N). The release force was 1.69N (Absolute), 2.05N (Astron Pulsar) up to 13.00N (Flexstar). The radial force for a 6 mm stent diameter during expansion ranged from 3.95N (Absolute) and 3.99N (Astron Pulsar) up to 7.22N (FlexStar) but was higher when compressed. Conclusion: The 4F system had the best flexibility and trackability. The release force was high in most systems with release handles. The radial force of all tested stents covers a broad range. These results could be helpful to find the best stent for different lesions. (orig.)
[en] We produced and measured over 800 32P-ion-implanted coils for pre-clinical and clinical studies. Platinum coils are intravascular implants most frequently used in the treatment of intracranial aneurysms. This less invasive endovascular approach is safer than conventional surgery, but a frequent drawback is the recurrence of the aneurysm, associated with recanalization, a phenomenon that can be inhibited by the local application of beta radiation. Total coil activities, uniformity, reproducibility and 32P binding to platinum were determined and found to be adequate for this application
[en] The injection of deuterium into the gate oxide film was achieved through two kind of method, high-pressure annealing and low-energy implantation at the back-end of line, for the purpose of the passivation of dangling bonds at SiO2/Si interface and SiO2 bulk. Experimental results are presented for the degradation of 3-nm-thick gate oxide (SiO2) under both negative-bias temperature instability (NBTI), hot-carrier injection (HCI), and constant voltage stresses using P and NMOSFETs. Annealing process was rather difficult to control the concentration of deuterium. This paper is focused on the improvement of MOS device reliability related to deuterium process. Because when the concentration of deuterium is redundant in gate oxide excess traps are generated and degrades the performance, we found annealing process did not show the improved characteristics in device reliability, compared to conventional process. However, deuterium ion implantation at the back-end process was effective method for the fabrication of the deuterated gate oxide. Device parameter variations under the electrical stresses depend on the deuterium concentration and are improved by low-energy deuterium implantation, compared to conventional process. Especially, we found that PMOSFET experienced the high voltage stress shows a giant isotope effect. This is likely because the reaction between 'hot' hole and deuterium is involved in the generation of oxide trap.
[en] The succeed of the use of biomaterials for orthopedic implant device is determined by its mechanical properties, chemical stability and biocompatibility in tissues and body fluids. The corrosion resistance is one of the main property of biomaterials to determine for successful orthopedic implant in body tissues. Surface modification is carried out to improve biomaterial surface properties of austenitic stainless steel 316L with nitrogen ion implantation technique and ion nitriding. Nitrogen ion implantation performed on 60 keV ion energy and ion dose variations 2 x 10"1"6 ions/cm"2- 2 x 10"1"7 ions/cm"2. The corrosion resistance of austenitic stainless steel 316L in Hanks solution is measured by using a potentiostat, and corrosion resistance optimum of a sample is obtained at an ion dose of 5 x 10"1"6 ions/cm"2 and increase by a factor of 2.1 if compared to the sample without the nitrogen ion implantation. Further the sample of austenitic stainless steel 316L with the optimum corrosion resistance is processed by ion nitriding technique at a nitriding temperature of 350 °C and nitriding time of 4 hours. Based on corrosion test of the sample produced by ion nitriding is obtained an increasing the corrosion resistance by a factor of 2.96 when compared to the sample before nitrogen ion implantation. The improvement of corrosion resistance of the sample is caused by the formation of iron nitride ξ-Fe2N and γ- Fe4N which has excellent corrosion resistance properties. (author)
[en] The lattice location of implanted silver in Si was studied by means of the emission channeling technique. Following 60 keV room temperature implantation of radioactive 111Ag at a dose of 2-3x1012 cm-2, we identify around 30% of Ag on near-substitutional sites (∼0.45 A from ideal S-sites). Upon annealing at 200-300 deg. C, the fraction on near-S sites reaches a maximum around 60-80%. For higher annealing temperatures it decreases again and at 600 deg. C Ag starts to diffuse out of the Si samples. We estimate the activation energy for the dissociation of near-substitutional Ag to be 1.8-2.2 eV. The experimental results are compared to those of Cu in Si, and common features and characteristic differences in the behavior of the two group 1B metals are discussed
[en] The diffusion of indium in both the top silicon and the buried oxide (BOX) layers in separation by implantation of oxygen (SIMOX) is investigated. For all indium-implanted samples, there is a significant redistribution of indium atoms from the top Si-BOX interface toward the bottom BOX-Si interface, thereby affecting the indium concentrations in the two silicon-BOX interfaces. In the case of relatively high-dose and high-energy indium implantation (1x1014 cm-2 at 200 keV), an anomalous segregation of indium is observed in both the bulk Si and the SIMOX substrates. However, there is a notable transportation of indium atoms from the top Si layer toward the bottom BOX-Si interface in the SIMOX, thereby affecting not only the indium concentrations in the two silicon-BOX interfaces but also the indium distribution in the top silicon layer. The unique indium-diffusion behavior in the SIMOX is believed to be a composite effect of indium trapping by the two Si-BOX interfaces, indium atoms being drawn away from the top silicon layer by the buried oxide, as well as implant damages in the top silicon. The asymmetrical structure of the BOX layer with Si islands accumulating at the bottom BOX-Si interface and the abundance of oxygen-related defects in the BOX layer are also believed to be responsible for the indium-diffusion behavior in the BOX layer
[en] The extent ('gate overlap') and slope ('abruptness') of the lateral junction are quickly replacing vertical junction depth as the most important physical junction metrics in advanced device architectures. This is in particular true for ultra-thin body devices, where the vertical junction is limited by a geometric constraint. The optimum gate overlap is quite small, or may even be negative, making a process without the need of high-tilt implantation feasible, even for dopant activation with negligible diffusion by flash annealing or laser thermal processing. Dopant activation by solid phase epitaxial regrowth might require high-tilt implants for a positive overlap. The use of such implants, however, is expected to lead to severe gate-poly and gate-oxide degradation. Scaling the 150 nm technology has drastically shrunk the overlap, accomplished by an equally aggressive reduction in thermal budget. For a 65 nm node device, a significant fraction of the overlap originates in the as-implanted dopant profile and the importance of diffusion is diminished. As a consequence small changes in the as-implanted profile are beginning to have a disproportionate impact on device characteristics. Small angular deviations of the incident beam from normal incidence, as seen by the wafer, lead to large changes in on-current. This can be alleviated significantly by a quad implant provided the tilt-angle is sufficiently large, in the order >5 deg.
[en] In this work we propose an alternative methodology to study B diffusion in crystalline Ge. We enhance B diffusion by means of passing implants in such a way to increase the point-defects distribution through the sample, well above the equilibrium value. A comparison between B diffusion occurring under implantation with different ions or after post-implantation annealing allowed to discern any possible role of ionization effects on B diffusion. Indeed, B diffusion is demonstrated to occur through a point-defect-mediated mechanism. The diffusion mechanism is hence discussed. These results are a key point for a full comprehension of the B diffusion in Ge.
[en] In this work we investigate the diffusion and the electrical activation of In atoms implanted into silicon with energies ranging from 40 to 360 keV and doses of 5x1012 and 5x1013 In/cm2 during rapid thermal processing. Our investigation shows a clear dependence of In outdiffusion and electrical activation on the implant depth. For a fixed dose, the electrical activation was found to increase with the implant energy. We propose that the data can be explained by considering the balance between the local In concentration and the C background. The occurrence of coupling between the C present in the substrate and the implanted In, depending on the C/In ratio, may in fact give rise to significant formation of C-In complexes. Such complexes play a role in the enhanced electrical activation due to the shallower level they introduce into the Si band gap (Ev+0.111 eV), with respect to the rather deep level (Ev +0.156 eV) of In alone [R. Baron et al., Appl. Phys. Lett. 30, 594 (1977); R. Baron et al., ibid. 34, 257 (1979)]. The interaction of In atoms with the C background inside the silicon substrate has been, therefore, identified as the most likely origin of this behavior. In and C coimplantation has also been studied in this work, in order to further investigate the key role of C in the increase of electrical activation. A large increase of electrical activation has been detected in the coimplanted samples, up to a factor of about 8 after annealing at 900 deg. C. However, C precipitation occurs at 1100 deg. C, and has dramatic effects on the carrier concentration that falls by even two orders of magnitude. This limits the maximum thermal budget that can be used for In activation in C coimplanted material
[en] The analysis of the kinetics of formation the dynamically stable nanostructures during implantation quartz glass Au"- ions and Cu"- with the energy of 60 keV in the framework of a one-dimensional model of the evolution of the distribution of implanted atoms in depth, taking into account the spray of the surface of the implanted layer, the production and the diffusion of the implanted mass, has been presented in the paper
[ru]В работе проведен анализ кинетики формирования динамически устойчивых наноструктур при имплантации кварцевого стекла ионами Au"- и Cu"- с энергией 60 кэВ в рамках одномерной модели эволюции распределения имплантированных атомов по глубине, учитывающей распыление поверхности имплантированного слоя, производство и диффузию имплантированной массы