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Characterization of zirconium nitride films sputter deposited with an extensive range of nitrogen flow rates J. Vac. Sci. Technol. A 26, 297 (2008); 10.1116/1.2839856 SPM oxidation and parallel writing on zirconium nitride thin films

Oxide growth on sputter-deposited thin films is studied on the local scale by atomic force microscope ͑AFM͒-assisted lithography. We investigate the group IV reactive metals Zr, Hf, Ti, and their nitrides. The nitrogen content of the deposition plasma affects the film crystal structure and electrical resistivity, which in turn alter the local oxidation rates. Mass transport plays an important role, producing features with heights ranging from a few nanometers up to hundreds of nanometers. The heights of the largest features are one to two orders of magnitude greater than observed in other material systems, and the growth is well controlled. We use various techniques to investigate the solid-state reaction and transport mechanisms involved in this oxidation driven by a highly localized electric field. Our results demonstrate the potential of AFM lithographic techniques for characterizing oxidation processes across a wide range of time and length scales.

SPM oxidation and parallel writing on zirconium nitride thin films J. Vac. Sci. Technol. A 23, 846 (2005); 10.1116/1.1864052 Effect of O 2 flow ratio on the microstructure and stress of room temperature reactively sputtered RuO x thin films J. Vac. Sci. Technol. A 23, 452 (2005); 10.1116/1.1875272 Parallel writing on zirconium nitride thin films by local oxidation nanolithography Appl. Phys. Lett. 85, 5691 (2004); 10.1063/1.1833569Influence of substrate bias on practical adhesion, toughness, and roughness of reactive dc-sputtered zirconium nitride films ZrN x films are deposited by rf magnetron sputtering using a wide range of nitrogen flow rates to control film properties. Scanned probe microscope ͑SPM͒ oxidation is presented as a complimentary characterization tool to x-ray diffraction, colorimetric, and four point probe analyses. The SPM oxidation behavior of the ZrN x films is related to their structural, optical, and electrical properties. Whereas stoichiometric ZrN films have applications as protective and/or decorative coatings, ZrN x films sputtered with higher nitrogen flow rates have potential applications in devices where arrays of high aspect ratio nanostructures would be useful.

This work is Part II of an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin-film materials using plasma-enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with aluminum materials under different operating conditions to observe changes in the coating morphology. This procedure begins with the sputtering of the coating material from a target. Part I ͓J. Appl. Phys. 98, 044303 ͑2005͔͒ focused on the sputtering aspect and transport of the sputtered material through the reactor. That reactor level model determines the concentration field of the coating material. This field serves as input into the present species transport and deposition model for the region surrounding an individual nanofiber. The interrelationships among processing factors for the transport and deposition are investigated here from a detailed modeling approach that includes the salient physical and chemical phenomena. Solution strategies that couple continuum and atomistic models are used. At the continuum scale, transport dynamics near the nanofiber are described. At the atomic level, molecular dynamics ͑MD͒ simulations are used to study the deposition and sputtering mechanisms at the coating surface. Ion kinetic energies and fluxes are passed from the continuum sheath model to the MD simulations. These simulations calculate sputtering and sticking probabilities that in turn are used to calculate parameters for the continuum transport model. The continuum transport model leads to the definition of an evolution equation for the coating-free surface. This equation is solved using boundary perturbation and level set methods to determine the coating morphology as a function of operating conditions.