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Background: Aging is a multifactorial process characterized by organ loss of function and degeneration, but the mechanisms involved remain elusive. We have shown recently that catecholamine metabolism drives the accumulation of mitochondrial DNA (mtDNA) deletions in dopaminergic cells, which likely contribute to their degeneration during aging. Here we investigated whether the well-documented degeneration and altered function of adrenals during aging is linked to catecholamine production in the medulla followed by accumulation of mtDNA deletions. Material and Methods: We analyzed adrenal medullary and cortical samples of both murine and human origin covering a wide range of ages for mtDNA deletion content, mtDNA copy number, mitochondrial and cellular integrity as well as aging-related tissue changes such as fibrosis. Results: Indeed, we demonstrate in mice and humans that the adrenal medulla accumulates a strikingly high amount of mtDNA deletions with age, causing mitochondrial dysfunction in the adrenal medulla, but also in the cortex, accompanied by apoptosis and, more importantly, by severe inflammation and remarkable fibrosis. Additionally, a concomitant and dramatic loss of medullary and cortical cells is observed in old animals. Conclusion: Our results show that accumulation of mtDNA deletions, and the ensuing mitochondrial dysfunction, is a hallmark of adrenal aging, further strengthening the hypothesis that catecholamine metabolism is detrimental to mtDNA integrity, mitochondrial function and cell survival. Moreover, the cell loss potentially induced by mitochondrial dysfunction could explain the decline in adrenal hormonal and steroidal secretion during aging. [ABSTRACT FROM AUTHOR]

The 3D spatial resolution, the material contrast and the evolution of the noise are analyzed in the reconstructed volume of a combined scanning transmission electron microscopy (HAADF-STEM) and energy dispersive x-ray spectroscopy (EDS) tomography experiment. Standard simultaneous iterative reconstruction technique and HAADF-EDS bimodal tomographic reconstruction are considered for the +/−90° tomography series of a pillar shaped sample embedding a full nanowire device. With a high number of iterations, a spatial resolution for both HAADF and EDS down to 5 nanometer can be reached for this volume. Best material’s contrast and minimum noise are obtained for medium number of iterations. Improvement of the signal-to-noise and contrast can be obtained by filtering the EDS data while the spatial resolution is not impacted. A fast and reliable preparation methodology for rectangularly shaped pillar samples for tomography analysis is discussed. [ABSTRACT FROM AUTHOR]

Advanced semiconductor devices have 3D morphologies with nanometer sized features. Therefore, their structural and chemical characterization requires analysis techniques with high spatial 3D resolution. Through focal integrated differential phase contrast and high angle annular dark field scanning transmission electron microscopy (STEM) depth sectioning are among the techniques that can potentially fulfill these needs. In this work they are applied to Si and Ge nanowire structures with gate all around replacement metal gates. It is shown that with both imaging modes slicing with 2D lattice resolution through the polycrystalline gate stack and the monocrystalline wires is possible, while a resolution in the viewing direction on the order of 5 nm is obtained. Based on fast Fourier transformation analysis the crystal distribution in the gate stack and morphology of the nanowires are analyzed. Similar structures are investigated with combined STEM-energy dispersive spectroscopy 180° tomography on pillar shaped TEM specimens. Comparison of the 3D imaging modes and standard TEM/STEM imaging is discussed. [ABSTRACT FROM AUTHOR]

During Cu/low-kdamascene integration, plasma ash can introduce a thin modified layer on the trench sidewall of low-kdielectrics. This plasma ash modified layer can influence the time-dependent dielectric breakdown (TDDB) lifetime distribution. In this paper, we investigated the plasma ash modified layer effect on the TDDB thermal activation energy of a CVD SiOC:H low-kdielectric (k= 3) integrated in Cu damascene structures. We found that for the 'non-modified' SiOC:H low-kdielectric combined with sealing metal diffusion barriers, the TDDB thermal activation energy is close to zero. With the introduction of a plasma ash modified layer, the apparent TDDB thermal activation energy increases. By means of thermal desorption spectroscopy on blanket films and energy-filtered TEM analysis on patterned structures, the increase of TDDB thermal activation energy is correlated with plasma ash induced moisture uptake in the CVD SiOC:H low-kdielectric. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNT) are known to be materials with potential for manufacturing sub-20 nm high aspect ratio vertical interconnects in future microchips. In order to be successful with respect to contending against established tungsten or copper based interconnects, though, CNT must fulfil their promise of also providing low electrical resistance in integrated structures using scalable integration processes fully compatible with silicon technology. Hence, carefully engineered growth and integration solutions are required before we can fully exploit their potentialities. This work tackles the problem of optimizing a CNT integration process from the electrical perspective. The technique of measuring the CNT resistance as a function of the CNT length is here extended to CNT integrated in vertical contacts. This allows extracting the linear resistivity and the contact resistance of the CNT, two parameters to our knowledge never reported separately for vertical CNT contacts and which are of utmost importance, as they respectively measure the quality of the CNT and that of their metal contacts. The technique proposed allows electrically distinguishing the impact of each processing step individually on the CNT resistivity and the CNT contact resistance. Hence it constitutes a powerful technique for optimizing the process and developing CNT contacts of superior quality. This can be of relevant technological importance not only for interconnects but also for all those applications that rely on the electrical properties of CNT grown with a catalytic chemical vapor deposition method at low temperature. [ABSTRACT FROM AUTHOR]