This paper describes the use of several methods of template stripping (TS) to produce ultraflat films of silver, gold, palladium, and platinum on both rigid and polymeric mechanical supports: a composite of glass and ultraviolet (UV)-curable adhesive (optical adhesive, OA), solder, a composite of poly(dimethyl siloxane) (PDMS) and OA, and bare OA. Silicon supporting its native oxide layer (Si/SiO2) serves as a template for both mechanical template stripping (mTS), in which the metal film is mechanically cleaved from the template, and chemical template stripping (cTS), in which the film-template composite is immersed in a solution of thiols, and the formation of the SAM on the metal film causes the film to separate from the template. Films formed on all supports have lower root-mean-square (rms) roughness (as measured by atomic force microscopy, AFM) than films used as-deposited (AS-DEP) by electron-beam evaporation. Monolayers of n-dodecanethiolate formed by the mTS and cTS methods are effectively indistinguishable by scanning tunneling microscopy (STM); molecularly resolved images could be obtained using both types of surfaces. The metal surfaces, before being cleaved, are completely protected from contact with the atmosphere. This protection allows metal surfaces intended to support SAMs to be prepared in large batch lots, stored, and then used as needed. Template stripping thus eliminates the requirement for evaporation of the film immediately before use and is a significant extension and simplification of the technology of SAMs and other areas of materials science requiring clean metal surfaces.

This communication describes the fabrication of gold structures (for example, rings) with wall thickness of 40 nm, and with high aspect ratios up to 25. This technique combines thin-film deposition of metal on a topographically patterned epoxy substrate, with nanometer-scale sectioning using a microtome in a plane parallel to the patterned substrate. The dimensions of the metal structures are determined by the thickness of the metal film and the thickness of the epoxy sections. The shape of the resulting nanostructure is defined by the cross-section of the original template.This paper describes the fabrication of gold nanostructures with high aspect ratios using a combination of thin film deposition and a recently developed technique based on sectioning with a microtome (which we call "nanoskiving"). 1 The dimensions of the resulting nanostructures are controlled by the thickness of the metal film and the thickness of the epoxy sections. The shape of the nanostructure is defined by the geometry of the template.High aspect-ratio microstructures have been used as the building blocks in a number of areas, such as microelectromechanical systems (MEMS), 2,3 two-dimensional subwavelength photonic bandgap (PBG) devices, 4-6 and sensors. Devices for high frequencies based on diffraction (e.g. Fresnel zone plates and diffraction gratings) and on refraction (e.g. wave plates and retarders) require both nanoscale dimensions and high aspect ratios for optimal operation. 7 A number of techniques have been developed to fabricate high aspect ratio micro-and nanoscale structures; these include X-ray LIGA, 8,9 deep reactive-ion etching (DRIE), 10 focused ion-beam etching, 11-13 and glancing-angle deposition (GLAD). 14,15 These techniques are, however, not conveniently available to general users. Simple and inexpensive techniques to fabricate nanostructures with high aspect ratio are highly desirable. 16The microtome has been used extensively for preparation of thin samples for imaging with optical or electron microscopy. 17,18 A microtome can generate polymer sections as thick as 10 μm with a rotary microtome system, and as thin as 10 nm when equipped with an oscillating diamond knife. 19 We have demonstrated previously the fabrication of conductive nanoelectrodes and nanowires based on thin-metal-film deposition and microtome sectioning using an ultramicrotome with a diamond knife. 1,20 Here we used a similar technique but with a different topography, to fabricate high aspect-ratio gold nanostructures of types that would be difficult or impossible to obtain by conventional lithographic techniques. Figure 1 shows the procedure used to fabricate 3D, free-standing metal nanostructures by thin film deposition and nanoskiving. First, we used standard soft-lithographic techniques to fabricate a PDMS replica of an array of micro-posts patterned in S1813 photoresist. then transferred these micro-posts onto epoxy (Araldite 502) by curing a layer of epoxy prepolymer against this PDMS stamp (step 1), using a gold-coated Si/SiO 2 w...

Smooth and continuous films of nickel nitride (NiN x ) with excellent step coverage were deposited from a novel nickel amidinate precursor, Ni(MeC(N t Bu)2)2, and either ammonia (NH3) or a mixture of NH3 and hydrogen (H2) gases as co-reactants. The reactants were injected together in direct-liquid-injection chemical vapor deposition (DLI-CVD) processes at substrate temperatures of 160−200 °C. Depending on the ratio of NH3 to H2 gases during deposition, the Ni:N atomic ratio in DLI-CVD NiN x films could be varied from ∼3:1 to ∼15:1, having either a cubic nickel structure or a mixture of hexagonal Ni3N and cubic Ni4N crystal structures with an incorporation of nitrogen as low as 6%. The chemical vapor deposition (CVD) growth rates of NiN x could be increased to more than 5 nm/min. The CVD films were smooth and continuous, and they had ∼100% step coverage in high-aspect-ratio (>50:1) holes. The as-deposited NiN x films had resistivities as low as ∼50 μΩ cm for film thicknesses of ∼25 nm. Annealing of the films in H2 at 160 °C or hydrogen plasma treatment at room temperature removed the nitrogen and led to pure nickel films.

Abstract(Sn,Al)O x composite films with various aluminum (Al) to tin (Sn) ratios were deposited using an atomic layer deposition technique. The chemisorption behavior of cyclic amide of tin(II) and trimethylaluminum were analyzed by Rutherford backscattering spectroscopy. Both precursors showed retarded and enhanced chemisorption on Al 2 O 3 and SnO 2 surfaces, respectively. The films show highly anisotropic electrical conductivity, i.e. much higher resistivity in the direction through the film than parallel to the surface of the film. The cause of the anisotropy was investigated by cross-sectional transmission electron microscopy, which showed a nanolaminate structure of crystalline SnO 2 grains separated by thin, amorphous Al 2 O 3 monolayers. When the Al concentration was higher than ~35 at.%, the composite films became amorphous, and the vertical and lateral direction resistivity values converged toward one value. By properly choosing the ratio of SnO 2 and Al 2 O 3 subcycles, controlled adjustment of film electrical resistivity over more than 15 orders of magnitude was successfully demonstrated.

Smooth, continuous, and highly conformal nickel nitride ͑NiN x ͒ films were deposited by direct liquid injection ͑DLI͒-chemical vapor deposition ͑CVD͒ using a solution of bis͑N,NЈ-di-tert-butylacetamidinato͒nickel͑II͒ in tetrahydronaphthalene as the nickel ͑Ni͒ source and ammonia ͑NH 3 ͒ as the coreactant gas. The DLI-CVD NiN x films grown on HF-last ͑100͒ silicon and on highly doped polysilicon substrates served as the intermediate for subsequent conversion into nickel silicide ͑NiSi͒, which is a key material for source, drain, and gate contacts in microelectronic devices. Rapid thermal annealing in the forming gas of DLI-CVD NiN x films formed continuous NiSi films at temperatures above 400°C. The resistivity of the NiSi films was 15 ⍀ cm, close to the value for bulk crystals. The NiSi films have remarkably smooth and sharp interfaces with underlying Si substrates, thereby producing contacts for transistors with a higher drive current and a lower junction leakage. Resistivity and synchrotron X-ray diffraction in real-time during annealing of NiN x films showed the formation of a NiSi film at about 440°C, which is morphologically stable up to about 650°C. These NiSi films could find applications in future nanoscale complementary metal oxide semiconductor devices or three-dimensional metal-oxide-semiconductor devices such as Fin-type field effect transistors for the 22 nm technology node and beyond.