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The amplitude dependent mechanical loss due to bosing of an idealized Frank-Read Source is studied using both simulation and analytical techniques. Dislocations are modeled within isotropic elasticity theory, and are assumed to be in the over-damped limit.

1. Introduction The multilayer ceramic capacitor (MLCC) [1, 2] is the 'workhorse of the electronic components industry' [3] and a pervasive and critical element for electrical decoupling, filtering, and many [...]

The strain field surrounding a spherical indentation in silicon is mapped in two dimensions (2-D) using electron backscatter diffraction (EBSD) cross-correlation and confocal Raman spectroscopy techniques. The 200mN indentation created a 4 μm diameter residual contact impression in the silicon (001) surface. Maps about 50 μm x 50 μm area with 128 pixels x 128 pixels were generated in several hours, extending, by comparison, assessment of the accuracy of both techniques to mapping multiaxial strain states in 2-D. EBSD measurements showed a residual strain field dominated by in-surface normal and shear strains, with alternating tensile and compressive lobes extending about three to four indentation diameters from the contact and exhibiting two-fold symmetry. Raman measurements showed a residual Raman shift field, dominated by positive shifts, also extending about three to four indentation diameters from the contact but exhibiting four-fold symmetry. The 2-D EBSD results, in combination with a mechanical-spectroscopic analysis, were used to successfully predict the 2-D Raman shift map in scale, symmetry, and shift magnitude. Both techniques should be useful in enhancing the reliability of microelectromechanical systems (MEMS) through identification of the 2-D strain fields in MEMS devices. [ABSTRACT FROM AUTHOR]

The random buckling patterns of nanoscale dielectric walls are analyzed using a nonlinear multiscale stochastic method that combines experimental measurements with simulations. The dielectric walls, approximately 200 nm tall and 20 nm wide, consist of compliant, low dielectric constant (low-k) fins capped with stiff, compressively stressed TiN lines that provide the driving force for buckling. The deflections of the buckled lines exhibit sinusoidal pseudoperiodicity with amplitude fluctuation and phase decorrelation arising from stochastic variations in wall geometry, properties, and stress state at length scales shorter than the characteristic deflection wavelength of about 1000 nm. The buckling patterns are analyzed and modeled at two length scales: a longer scale (up to 5000 nm) that treats randomness as a longer-scale measurable quantity, and a shorter-scale (down to 20 nm) that treats buckling as a deterministic phenomenon. Statistical simulation is used to join the two length scales. Through this approach, the buckling model is validated and material properties and stress states are inferred. In particular, the stress state of TiN lines in three different systems is determined, along with the elastic moduli of low-k fins and the amplitudes of the small-scale random fluctuations in wall properties--all in the as-processed state. The important case of stochastic effects giving rise to buckling in a deterministically sub-critical buckling state is demonstrated. The nonlinear multiscale stochastic analysis provides guidance for design of low-k structures with acceptable buckling behavior and serves as a template for how randomness that is common to nanoscale phenomena might be measured and analyzed in other contexts. [ABSTRACT FROM AUTHOR]

A methodology to decouple irregular small-scale roughness and regular long-range features on deep reactive ion etched (DRIE) silicon surfaces is presented. Height-height correlations of three different DRIE silicon surfaces are evaluated via atomic force microscopy height data and fit to an analytic, five-parameter model based on a phenomenological scaling function for the small-scale roughness and a Bessel function for the long-range features. The resulting roughness parameters are constant for all three surfaces at small lateral length scales, indicating self-affine roughness inherent to the DRIE process, but dependent on the etch process at large lateral length scales, increasing by a factor of five as the controlled portion of the DRIE process decreased. The results from the analysis are also compared to fracture strengths from recently introduced 'theta' test samples with the same etch features as an example of the potential of the analysis in providing an unbiased assessment of the processing-structure-property relationships for DRIE silicon surfaces. [ABSTRACT FROM AUTHOR]

Thermal-field directed self-assembly (TDSA) of epitaxial self-assembled quantum dots (SAQDs) is the method of using spatially varying temperature patterns to influence SAQD growth kinetics and ultimately the order and positions of SAQDs. The effectiveness of TDSA in enhancing the size and spatial order or precision placement of single dot or dot cluster is investigated via a two dimensional (one dimensional surface) finite element based model of Ge dots grown on Si. Three different cases of heating are studied, namely, spatially constant heating, spatially periodic heating, and a Gaussian shaped hot spot. Statistical measures are used to study the evolution of quantum dot heights and spacings between the quantum dots for different temperatures and heating cases. Spatially periodic heating is investigated for a wavelength of about 185 nm corresponding to the wavelength of an excimer laser. In order to investigate the effectiveness of spatially periodic heating in enhancing the spatial and size order of the SAQD array, the results are compared with those obtained from spatially uniform heating. Simulations using Gaussian shaped hot spot are performed to demonstrate its effectiveness in placing a distinct dot at a desired location. Results from the simulations indicate that spatially periodic heating proves to be an effective means for producing an array of uniformly sized and spaced quantum dots for a broad range of temperatures. Also, the results from the simulations using Gaussian shaped hot spots show that such a form of heating can effectively place a distinct quantum dot near a desired location for a broad range of temperature values. [ABSTRACT FROM AUTHOR]

Elastically inhomogeneous multilayer films are being exploited for use as ultra-hard coatings. These films exhibit a strong dependence between the compositional wavelength of the film, ?, and the hardness, H = K ? -a + H 0 where the scaling exponent a depends on the elastic properties of the individual layers (shear moduli and Poisson ratios). The dislocation pileup model can explain this trend and form a bridge between the microscopic strength of multilayer interfaces and the macroscopic strength of the multilayer. A semianalytic solution to the pileup model of multilayer strength is presented. All parameter dependencies are solved analytically except a single dimensionless coefficient which is found from numerical simulation. The predictions are compared to data from a 2D discrete dislocation model and to experimental Cu/Ni data. Coefficients and exponents are given for some additional material systems. [ABSTRACT FROM AUTHOR]

The primary tool for mechanical charaterization of surfaces and films is instrumented indentation using the Oliver-Pharr data analysis method. However, this method measures contact area between the indenter and sample indirectly, thus confounding instrumented indentation tests when characterizing dynamic properties, thin films, and materials that "pileup" around the indenter. Here, we demonstrate an electrical technique to continuously measure the in situ contact area by relating nonlinear electrical contact current-voltage (I-V) curves to the instantaneous contact area. Using this approach, we can obtain hardness as a continuous function of applied force. [ABSTRACT FROM AUTHOR]