Finite Size Effects in Highly Scaled Ruthenium Interconnects

Ru has been considered a candidate to replace Cu-based interconnects in VLSI circuits. Here, a methodology is proposed to predict the resistivity of (Ru) interconnects. First, the dependence of the Ru thin film resistivity on the film thickness is modeled by the semiclassical Mayadas-Shatzkes (MS) approach. The fitting parameters thus obtained are then used as input in a modified MS model for nanowires to calculate wire resistivities. Predicted experimental resistivities agreed within about 10%. The results further indicate that grain boundary scattering was the dominant scattering mechanism in scaled Ru interconnects.Comment: 4 pages. 2 figure

Temperature-Dependent Resistivity of Alternative Metal Thin Films

The temperature coefficients of the resistivity (TCR) of Cu, Ru, Co, Ir, and W thin films have been investigated as a function of film thickness below 10 nm. Ru, Co, and Ir show bulk-like TCR values that are rather independent of the thickness whereas the TCR of Cu increases strongly with decreasing thickness. Thin W films show negative TCR values, which can be linked to high disorder. The results are qualitatively consistent with a temperature-dependent semiclassical thin film resistivity model that takes into account phonon, surface, and grain boundary scattering.Comment: 11 pages, 4 figure

Reservoir quality controls on Rotliegend fluvio-aeolian wells in Germany and the Netherlands, Southern Permian Basin – Impact of grain coatings and cements

Reservoir quality in sandstones can be a function of temperature, pressure, and chemical alterations over time. Some intrinsic properties of sandstones can additionally impact the evolution of reservoir quality. The detrital composition, depositional environment, and properties controlled thereby, dictate some of the diagenetic changes. Extrinsic processes, like external fluids, e.g. from hydrothermal events or dewatering of clay minerals, can additionally result in changes of reservoir quality. One of these properties are grain coatings on quartz grains, which can strongly affect pore cementation by quartz overgrowths. To predict and infer the quality of undrilled reservoirs, constraints are needed to predict their occurrence. We analyse two reservoir settings in the Southern Permian Basin and delineate the impact of depositional systems, lithologies, detrital and authigenic composition on reservoir quality and with regard to grain coatings. Results highlight the importance of diagenetic alterations and the source area in regards to burial development in different parts of the Southern Permian Basin. Samples from the Rotliegend Bahnsen Sandstone Member from Germany and the Slochteren Sandstone Formation from the Netherlands have been petrographically and petrophysically analysed and linked to depositional environments. Our data shows that the emplacement and presence of grain coating minerals cannot be simply linked to the depositional environment or processes controlled thereby (e.g. grain size and sorting), neither on a reservoir-, nor on a basin scale. The dissolution of alumosilicates additionally has no consistent impact on the authigenesis of chloritic grain coatings on the reservoir- or basin scale in this study. This implies the necessity of sample specific analyses and importance of the assessment of diagenetic alterations when analysing, modelling, or predicting reservoir quality in similar settings worldwide

Large anisotropic uniaxial pressure dependencies of Tc in single crystalline Ba(Fe0.92Co0.08)2As2

Using high-resolution dilatometry, we study the thermodynamic response of the lattice parameters to superconducting order in a self-flux grown Ba(Fe0.92Co0.08)2As2 single crystal. The uniaxial pressure dependencies of the critical temperature of Tc, calculated using our thermal expansion and specific heat data via the Ehrenfest relation, are found to be quite large and very anisotropic (dTc/dpa = 3.1(1) K/GPa and dTc/dpc = - 7.0(2) K/GPa). Our results show that there is a strong coupling of the c/a ratio to superconducting order, which demonstrates that Tc is far from the optimal value. A surprising similarity with the uniaxial pressure effects in several other layered superconductors is discussed.Comment: 11 pages, 4 Figure

First principles-based screening method for resistivity scaling of anisotropic metals

The resistivity scaling of metals is a crucial factor for further downscaling of interconnects in nanoelectronic devices that affects signal delay, heat production, and energy consumption. Here, we present a screening method for metals with highly anisotropic band structures near the Fermi level with the aim to select promising materials in terms of their electronic transport properties and their resistivity scaling at the nanoscale. For this, we consider a temperature-dependent transport tensor, based on band structures obtained from first principles. This transport tensor allows for a straightforward comparison between different anisotropic metals in nanostructures with different lattice orientations. By evaluating the temperature dependence of the tensor components, we also find strong deviations from the zero-temperature transport properties at standard operating temperature conditions around room temperature.Comment: 25 pages, 8 figure

Spin wave emission by spin-orbit torque antennas

We study the generation of propagating spin waves in Ta/CoFeB waveguides by spin-orbit torque antennas and compare them to conventional inductive antennas. The spin-orbit torque was generated by a transverse microwave current across the magnetic waveguide. The detected spin wave signals for an in-plane magnetization across the waveguide (Damon-Eshbach configuration) exhibited the expected phase rotation and amplitude decay upon propagation when the current spreading was taken into account. Wavevectors up to about 6 rad/$\mu$m could be excited by the spin-orbit torque antennas despite the current spreading, presumably due to the non-uniformity of the microwave current. The relative magnitude of generated anti-damping spin-Hall and Oersted fields was calculated within an analytic model and it was found that they contribute approximately equally to the total effective field generated by the spin-orbit torque antenna. Due to the ellipticity of the precession in the ultrathin waveguide and the different orientation of the anti-damping spin-Hall and Oersted fields, the torque was however still dominated by the Oersted field. The prospects for obtaining a pure spin-orbit torque response are discussed, as are the energy efficiency and the scaling properties of spin-orbit torque antennas.Comment: 20 pages, 5 figure