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The article discusses the advanced characterization of materials in electronic devices using atom probe tomography (APT). APT, providing sub-nanometer 3D maps with high analytical sensitivity, is highlighted for its role in understanding failure modes influenced by material choice, processing methods, and service conditions. Topics include the evolution of APT, experimental overview, scope of material characterization, and examples of its applications in electronic devices.

1. IntroductionMultiwall carbon nanotubes (MWCNTs) play a role in the emerging nanotechnology industry due to the combination of desirable mechanical, thermal, and electrical properties [1]. The global production of MWCNTs [...]

We compare ferromagnetic resonance measurements of Permalloy Ni80Fe20 (Py) films sputtered onto Cu(111) films with and without a graphene (Gr) interlayer grown by chemical vapor deposition before Py deposition. A two-angle sputtering method ensured that neither Gr nor Py was degraded by the sample preparation process. We find the expected damping enhancement from spin pumping for the Py/Cu case and no detectable enhancement for the Py/Gr/Cu case. Since damping is sensitive to effects other than spin pumping, we used magnetometry to verify that differences in Py magnetostatic properties are not responsible for the difference in damping. We attribute the suppression of spin pumping in Py/Gr/Cu to the large contact resistance of the Gr/Cu interface. [ABSTRACT FROM AUTHOR]

While carbon nanotubes (CNT) have been suggested as thermal management material for integrated circuits, the thermal properties, and, especially, the thermal boundary resistance (TBR) of as-grown CNT fabricated at low temperature have hardly been investigated. Here, the thermal resistance of CNT vias, with different bundle lengths and diameters fabricated at 500°C using chemical vapour deposition, are investigated using the 3ω-method. It was found that the thermal resistance hardly changes with length except for the smallest bundle diameter of 2 μm, indicating that the TBR (109-1010K/W per tube) dominates the thermal conduction. This is in contrast to the electrical resistance and temperature coefficient of resistance, both of which clearly increase with length. From the slope of the thermal resistance versus length of the 2 lm wide bundles, the thermal conductivity of the CNT was estimated to be 1.4-2.8 W/mK. This low thermal conductivity is attributed to the low quality of the samples as determined by Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Films of (111)-textured Cu, Ni, and CuxNiy were evaluated as substrates for chemical vapor deposition of graphene. A metal thickness of 400 nm to 700 nm was sputtered onto a substrate of α-Al2O3(0001) at temperatures of 250 °C to 650 °C. The films were then annealed at 1000 °C in a tube furnace. X-ray and electron backscatter diffraction measurements showed all films have (111) texture but have grains with in-plane orientations differing by 60°. The in-plane epitaxial relationship for all films was [110]metal||[1010]Al2O3. Reactive sputtering of Al in O2 before metal deposition resulted in a single in-plane orientation over 97% of the Ni film but had no significant effect on the Cu grain structure. Transmission electron microscopy showed a clean Ni/Al2O3 interface, confirmed the epitaxial relationship, and showed that formation of the 60° twin grains was associated with features on the Al2O3 surface. Increasing total pressure and Cu vapor pressure during annealing decreased the roughness of Cu and CuxNiy films. Graphene grown on the Ni(111) films was more uniform than that grown on polycrystalline Ni/SiO2 films, but still showed thickness variations on a much smaller length scale than the distance between grains. [ABSTRACT FROM AUTHOR]

Three-dimensional atom-probe tomography and transmission electron microscopy have been utilized to study the effects of Ta getter presputtering and either a Mg or Ru free-layer cap on the elemental distributions and properties of MgO-based magnetic tunnel junctions after annealing. Annealing the samples resulted in crystallization of the amorphous CoFeB layer and diffusion of the majority of the boron away from the crystallized CoFeB layers. The Ta getter presputter is found to reduce the segregation of boron at the MgO/CoFeB interface after annealing, improving the tunneling magnetoresistance of the tunnel junction. This effect is observed for samples with either a Ru free-layer cap or a Mg free-layer cap and is thought to be a result of a reduced oxygen concentration within the MgO due to the effect of Ta getter presputtering. A Ru free-layer cap provides superior magnetic and magnetotransport properties compared to a Mg free-layer cap. Mg from the Mg free-layer cap is observed to diffuse toward the MgO tunnel barrier upon annealing, degrading both the crystalline quality of the CoFeB and magnetic isolation of the CoFeB free-layer from the CoFeB reference-layer. Lateral variations in the B distribution within the CoFeB free-layer are observed in the samples with a Ru free-layer cap, which are associated with crystalline and amorphous grains. The B-rich, amorphous grains are found to be depleted in Fe, while the B-poor crystalline grains are slightly enriched in Fe. [ABSTRACT FROM AUTHOR]