The effect of Ta and Ta/Cu seed layers, and Ta and Cu cap layers on the effective magnetic thickness of ultrathin permalloy (Ni81Fe19) was investigated for MRAM applications. The films were deposited by Ion Beam Deposition. The magnetic moment of each as-deposited permalloy film was measured using a B-H looper and a SQUID magnetometer. The films were further annealed at either 525 K for 1/2 h or 600 K for 1 h to study the effect of thermally driven interdiffusion on the magnetic moment of the permalloy film. Our theoretical calculations showed that the presence of 12% intermixing at the interface reduces the Ni moments to zero. Experimentally, it was shown that the tantalum rather than the copper interfaces are primarily responsible for the magnetically dead layers. The Ta seed layer interface produces a loss of moment equivalent to a magnetically dead layer of thickness 0.6±0.2 nm. The Ta metal in the cap layer results in a loss of moment equivalent to a dead layer of thickness 1.0±0.2 nm. Upon annealing, thermally driven interdiffusion is concluded to have a strong effect on the Ta(seed)/ Ni81Fe19 as-deposited interface, based on the doubling of the magnetically dead layer to 1.2±0.2 nm. The Ni81Fe19/Ta(cap) as-deposited interface slightly increases its equivalent magnetically dead layer upon annealing to 1.2±0.2 nm. As-deposited interfaces of Ta(seed)/permalloy and permalloy/Ta(cap) are not chemically equivalent and result in different magnetically dead layers, whereas after annealing to 600 K both interfaces attain comparable intermixing and magnetically dead layers. It was also shown that a half-hour anneal at the lower 525 K annealing temperature, which is closer to the actual processing temperature, results in only slight increase of the magnetically dead layer at both interfaces.

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An oxygen-doped silicon carbide ͑O-SiC͒ barrier film with a dielectric constant of 3.3 was tested using a downstream ashing plasma tool. We investigated the interactions of three plasma chemistries, O 2 /H 2 /N 2 , H 2 /N 2 , and H 2 /He plasmas, with the O-SiC films. The plasma damage to the films were evaluated and chemical structure changes were examined. While the O 2 /H 2 /N 2 plasma changed the O-SiC film into a SiO 2 -like film, the H 2 /He plasma caused minimum damage to the film, and material removal can be controlled within 5%. The infrared spectra indicate no noticeable chemical structure changes after the H 2 /He plasma exposures. Further, the electrical properties, including dielectric constant, leakage current, and dielectric breakdown voltage, were measured after the films were exposed to these plasmas. These electrical characteristics are preserved after the films were exposed to the H 2 /He plasma. The results indicate that the H 2 /He plasma ashing chemistry can be effectively applied to the O-SiC films without generating degradation of the key film characteristics.

Specular X-ray reflectivity ͑SXR͒ was employed to compare structure and barrier properties of a series of nanoporous organosilicate low dielectric constant ͑low-k͒ thin films cured by several different techniques. The polymethylsilsesquioxane films were prepared by curing the same starting material by five different techniques: standard furnace cure, a novel UV light-assisted process, and three plasma-assisted processes. The films' electron density vs. depth profile, pore volume fraction, and moisture uptake were measured by SXR. The measurements illustrate how curing technology can significantly impact low-k film structure and barrier properties and also illustrate the value of SXR for characterization of depth-dependent phenomena in nanoporous thin films.