Abstract-Pulsed-current controlled wall motion in 20 m wide 200 m long 160 nm thick patterned Permalloy strips was studied using magnetic force microscopy. By sequential imaging, the displacement of Bloch walls as far as 200 m along the strip was observed. The direction of motion was in the same direction as the carrier velocity, which reversed with current polarity. The displacement per pulse was dependent upon the sample thickness and current density, which suggests that the mechanism is a combination of s-d exchange and hydromagnetic domain drag forces.

The generality of the curvature-enhanced accelerator coverage ͑CEAC͒ model of superconformal electrodeposition is demonstrated through application to superconformal filling of fine trenches during silver deposition from a selenium-catalyzed silver cyanide electrolyte. The CEAC mechanism involves ͑i͒ increase of local metal deposition rate with increasing coverage of a catalytic species adsorbed on the metal/electrolyte interface and ͑ii͒ significant change of local coverage of catalyst ͑and thus local deposition rate͒ in submicrometer features through the changing area of the metal/electrolyte interface. Electrochemical and X-ray photoelectron experiments with planar electrodes ͑substrates͒ are used to identify the catalyst and obtain all kinetic parameters required for the simulations of trench filling. In accord with the model, the electrolyte yields optically shiny, dense films, hysteretic current-voltage curves, and rising current-time transients. Experimental silver deposition in trenches from 350 down to 200 nm wide are presented and compared with simulations based on the CEAC mechanism. All kinetics for the modeling of trench filling come from the studies on planar substrates. The results support the CEAC mechanism as a quantitative formalism for exploring morphological evolution during film growth.Superconformal electrodeposition of copper in the Damascene process for microelectronic fabrication is enabling a new generation of integrated circuits. The use of copper interconnections has permitted faster clock speeds, enhanced reliability, and lower processing cost. Central to the success of the electrodeposition process is its ability to yield void and seam-free filling of high aspect ratio features. Empirically, such superfilling of trenches and vias with copper results from more rapid metal deposition ͑growth͒ at the bottom of the feature than at the sidewalls. Early models of superfilling of copper in trenches assumed location-dependent growth rates derived from diffusion-limited accumulation of only an inhibiting species. 1,2 Such models were unable to predict several key experimental observations. 3-6 Understanding of the superfill phenomena has improved substantially in the past two years. Electrolytes for the study of superconformal electrodeposition of copper have been fully disclosed. 6,7 A correlation between efficacy for superconformal filling of fine features, hysteresis in cyclic current-voltage studies, and recrystallization of deposits has also been demonstrated. 6 In addition, the curvature-enhanced accelerator coverage ͑CEAC͒ mechanism has been used to quantitatively predict superconformal copper deposition in trenches. [8][9][10][11] and vias 12 by electrodeposition as well as by surfactant-catalyzed chemical vapor deposition ͑CVD͒. 13,14 The CEAC mechanism involves the gradual accumulation of a metal-deposition-rate-accelerating species at the surface of the growing metal. If there is a deposition-rate-inhibiting species, it is presumed to be weakly bound and displaced, or altered, by th...

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We have carried out an extensive search for credible evidence to support the existence of a ballistic magnetoresistance ͑BMR͒ effect in magnetic nanocontacts. We have investigated both thin-film and thin-wire geometries for both mechanically formed and electrodeposited nanocontacts. We find no systematic differences between mechanically formed and electrodeposited nanocontacts. The samples we have investigated include mechanical contacts between ferromagnetic wires, electrodeposited nanocontacts between ferromagnetic wires, ferromagnetic nanocontacts electrodeposited on Cu wires, nanocontacts electrodeposited between ferromagnetic films anchored on wafers, ferromagnetic nanocontacts electrodeposited on Cu films anchored on wafers, nanocontacts between two ferromagnetic films connected by a pinhole through an insulating film, and nanocontacts formed by focused ion-beam etching. In none of these samples did we find credible evidence for a BMR effect. However, we did find a number of artifacts due to magnetostrictive, magnetostatic, and magnetomechanical effects that can mimic BMR.

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