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In this technical note, we demonstrate a squeeze-film based spacer-free method for creating controllable submicrometer hydrogel films on planar substrates that can be used to photolithographically fabricate hydrogel microstructures. This new technique improves the photolithographic resolution and yield by providing a uniform and low-defect hydrogel film. The optimum polymerization initiation time for achieving such a layer was determined to be around 1 min. For patterning, the dried hydrogel film was coated with a parylene-C masking layer. Subsequent etching in oxygen plasma was used to transfer selected patterns of hydrogel to the substrate in a batch scale. 10.1021/ac100579v

The controlled electrophoretic deposition of polystyrene/divinyl/benzene (PS/DVB) star polymer films from a colloidal suspension is demonstrated. The nanostructured films could be utilized in optical and biological device applications.

A method is presented to arbitrarily move and orient a set of rod-shaped conductive particles in a region defined by a set of electrodes using positive dielectrophoretic forces. The use of control of a single nanorod as an example shows that the desired orientation and force is produced for a small distance around the rod.

We present the first known implementation of a passive, scalable architecture for trapping, imaging, and sorting individual microparticles, including cells, using a positive dielectrophoretic (p-DEP) trapping array. Our array-based technology enables 'active coverslips' where, when scaled, many individually held cells can be sorted based upon imaged spatial or temporally variant characteristics. Our design incorporates a unique 'ring-dot' p-DEP trap geometry organized in a row/column array format. This trap design, implemented in a two-level metal process, provides strong and highly spatially localized holding fields enabling single-cell capture for all traps in the array. We release individual trapped microparticles during sorting using a passive transistor-independent approach where we electrically ground the row and column electrodes associated with specific traps in the array. The demand for chip-to-world electrical connections in our arrays scales proportionally with the square root of the number of traps in a given array, delivering a substantial improvement over prior designs. We demonstrate capture, holding, and release operations with both beads and cells in small arrays of this new architecture.

Control over the current during electrophoretic drawing of continuous fibers of single-walled carbon nanotubes (SWCNTs) is shown to be critical in producing long fibers with specific diameters. Control of the total current at low values during the process has the potential to produce long fibers with uniform submicron diameters.

Coaxial of carbon nanotubes (CNTs) with various inorganic materials are performed using pulsed laser deposition. The morphology and crystallinity of the coated layers were found to differ according to the materials used even at the same deposition temperature.

Ferroelectric thin films of BaTiO3 and BaTiO3/SrRuO3 epitaxial heterostructures on different single-crystalline substrates were fabricated by pulsed laser deposition. The BaTiO3 films of 100-400 nm thickness show high structural perfection and c-axis-oriented growth.

Microwave discharges of H2 admixed with CH4 in a moderate-pressure quartz bell jar reactor used for diamond deposition are studied numerically. The main chemical paths are identified, and the major species, transport effects, and reaction pathways that govern diamond plasmas are discussed.

A procedure for the electroless deposition of silver on films containing 99.5 percent aluminum and 0.5 percent copper is described. The deposition proceeds via the galvanic displacement mechanism by which the silver cations are reduced and copper is oxidized.

An alternate application of MgO film for the improvement of discharge characteristics and lifetime in an ac plasma display panel (PDP) is suggested. Results showed that PDP and MgO coated phosphor has more uniform formative delays in address discharges and improved degradation characteristics.

Abstract--Focused ion beam (FIB) systems are commonly used to image, repair and modify integrated circuits by cutting holes in passivation to create vias or to selectively break metal tracks. The ion beam can also be used to deposit a metal, such as platinum, to create new connections. These techniques are very useful tools for debugging designs and testing possible changes to the circuit without the expense of new mask sets or silicon. This paper presents test structures which can be used to characterize a FIB induced platinum deposition process. Sheet resistance test structures have been fabricated using a FIB tool and the results of testing these structures are presented. The sheet resistance data has been used to fabricate platinum straps with a known resistance. This extends the capability of the focused ion beam system beyond the deposition of simple conducting straps. The design of the test structures has been improved through the use of current flow simulation to investigate the effects of geometry and misalignment on the measurement accuracy. The results of these simulations are also presented. Index Terms--Deposition, FIB, focused ion beam, metrology, organometallic, sheet resistance, simulation, test structures, van der Pauw method.

In this paper, we have shown that the sputter etch before cobalt deposition during the silicide processing of a deep submicron CMOS device fabrication needs to be optimized in order to eliminate a detrimental origin of gate (G) to source (S)/drain (D) bridging. It is known that Co cannot reduce even a thin layer of native oxide. Therefore, it is necessary to ensure that Co is deposited on a very clean Si surface. To ensure this, an in-situ sputter etch is commonly conducted before Co deposition. It is observed that this sputter etch process can sputter Si from the S/D area and deposit them on the sidewall spacer (SWS). This sputtered Si in turn will react with deposited Co and form silicide. The worst case leakage currents from poly-Si to composite for long (10 m) and narrow (0.18 micron) poly lines are shown to be on the order of milliampere. Transmission electron microscope (TEM) micrographs included show the existence of cobalt silicide layers (~ 8 nm thick) over sidewall spacer. The silicide thickness on the sidewall spacer is correlated with resistance value calculated from current and voltage (I-V) measurements. The need for optimizing the sputter etch recipe has been validated by TEM and I-V measurements. Index Terms--CMOS processing, cobalt silicide, G to S/D bridging, sidewall spacer, sputter etch.

We previously introduced a vacuum deposition interface for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF MS) on a moving surface (e.g., quartz wheel, Mylar tape, metal target). In our present work, the approach has been extended to demonstrate parallel analysis for multiple on-line infusion MALDI MS and capillary array electrophoresis (CAE)-MALDI MS. In the infusion mode, individual peptide samples were simultaneously deposited on a Mylar tape cartridge using an array of eight capillaries, yielding eight parallel traces. For CAE-MALDI/TOF MS, the same number of separation capillaries were coupled with an array of eight infusion capillaries using a common liquid junction, containing matrix solution. A fast-scanning mirror was employed to traverse the beam of the desorption laser across the Mylar tape to probe one trace at a time. The positions of the eight sample traces formed on the tape were automatically determined, and all samples were analyzed in rapid sequence using a kilohertz repetition rate laser and a high-throughput data acquisition system. The instrumentation was operated with CAE MS for high-throughput analysis without compromising data quality. The principles of parallel separation--vacuum deposition should be generally applicable to MALDI/TOF MS analysis for proteomics and other areas where separation and high throughput are required.

The preparation of Pt-group metal films on roughened gold electrodes by utilizing spontaneous redox replacement of an underpotential-deposited (upd) copper or lead monolayer with a Pt-group metal cation solute is described. The resulting films display intense surface-enhanced Raman scattering (SERS) for adsorbates bound to the overlayer and free from substrate interferences. This strategy provides a useful alternative, at least for platinum, to the constant-current electrodeposition method commonly utilized to prepare SERS-active Pt-group metal films (Zou, S.; Weaver, M. J. Anal. Chem. 1988, 70. 2387). Similarly to related earlier studies, the film uniformity (specifically, the absence or otherwise of residual Au 'pinhole' sites) was tested by employing carbon monoxide, and also ethylene, as 'probe' chemisorbates, since they yield vibrational frequencies on Au that are blue-shifted from the corresponding bands for adsorbate bound to Pt-group metal sites. While a single redox replacement of upd Cu with Pt(IV) yielded incomplete surface coverage, as expected, the use of multiple (up to eight) replacement cycles produced Pt films displaying remarkably intense CO vibrational bands as well as apparently 'pinhole-free' properties, although such imperfections were detected with the ethylene probe. A single upd Cu replacement with Pt(II), however, yielded a remarkably uniform Pt layer, as indicated by pinhole-free characteristics using both the CO and ethylene probes along with the voltammetric behavior. The use of additional redox replacement cycles yielded marked progressive attenuation in the SERS signals. Comparable, although less optimal, SERS behavior was obtained for Pd films prepared similarly from Pd(II). The value of the strategy for exploring catalytic as well as equilibrium adsorptive chemistry on Pt surfaces is also illustrated.

A blanket tungsten layer direct deposition method on SiO2 was developed by utilizing helium plasma preexposure. After an hour of exposure of helium plasma, Si-Si bonds were formed on the surface of SiO2. Also, the relationship between the thickness of the SiO2 and the etching time in a HF solution of 0.063% was shown. It was recommended that a proper plasma-exposure time must be identified due to the observed peeling off of the tungsten layer at its interface with the Si substrate.

A microdeposition technique for carbon nanotubes based on electron beam lithography was presented. Carbon nanotubes were taken from the solution phase and deposited onto a substrate through openings that vary in size which are lithographically determined in an electron beam resist layer. The technique was used in depositing individual nanotubes on top of gold electrodes using alignment markers.

A method to reduce macroparticles, increase the deposition rate, and improve the coating quality in the cathodic vacuum arc deposition process is suggested. This method is based on the creation of emission-active phases on the cathode surface, and changing the melting point of surface layers of the cathode material and its work function. TiN coatings with a surface roughness of about 0.02 [[micro]meter] and microhardness [H.sub.v] about 4000 were deposited (compared with 0.085 [[micro]meter] Ra and 2900 [H.sub.v] for the conventional process). The method was successfully employed for the deposition of smooth coatings of AlN, (Ti,Al)N, and other compounds. Index Terms - Coatings, reactive gas, vacuum arc.

A filtered cathodic arc source has been used to deposit thin films of titanium nitride. The properties of the films are influenced by the nature of the condensation process. TiN films may be deposited directly onto heated substrates in a nitrogen atmosphere or onto unbiased substrates at ambient temperature by condensing the [Ti.sup.+] ion beam under [Mathematical Expression Omitted] nitrogen ion bombardment. In the latter case, the film stoichiometry was varied from an N:Ti ratio of 0.8 to 1.2 by controlling the relative arrival rates of Ti and nitrogen ions. Simple models are used to describe the evolution of compressive stress as a function of arrival ratio and the composition of the [Mathematical Expression Omitted] ion-assisted TiN films. Index Terms - Cathodic arc, stoichiometry, stress, thin films, titanium nitride.

Hydrogen-free amorphous carbon films with hardness comparable to crystalline superhard materials have been deposited by special pulsed arc techniques. With the combination of very high hardness, high smoothness, and low adhesion activity to other materials which are in contact with them, these films show superior behavior in wear and slide applications. The influence of plasma and deposition conditions on these film properties and the choice of optimum conditions are discussed.

Ion beam assisted deposition is used to create textured yttria-stabilized-zirconia buffer layers on flexible nickel substrates prior to the preparation of high current YBa2Cu3O7-gamma thick films. This approach enables the formation of c-oriented thick films with strong in-plane textures. The films produced using this method also exhibit excellent resistance to high magnetic fields at cryogenic temperatures.

The KrF pulsed laser deposition technique is used to prepare a YBaCuO thin film on a flexible metallic substrate with a yttria-stabilized zirconia (YSZ) buffer layer for suppressing the interdiffusion between the substrate and the film. The use of the YSZ layer allows optimum control of the c-axis arrangement and orientation of the thin film by minimizing the formation of particles.

A new method is proposed for the in situ deposition of high quality yttrium barium copper oxide (YBCO) films at a substrate temperature of over 700 degrees centigrade. The method uses yttria-stabilized zirconia as a buffer layer to enable the substrate to absorb the radiant heat and obtain c-axis oriented films. The applicability of the proposed deposition method is validated by its application on the preparation of YBCO films on lanthanum aluminate and sapphire substrates.

The utilization of organic molecular beam deposition in the fabrication of an ultrathin alternating layer organic superlattice film is discussed. Small angle x-ray diffraction and secondary ion mass spectrometry were used to confirm the periodic structure of the film. Fourier-transform infrared spectroscopy ans atomic force microscopy were used to examine molecular orientation and surface morphology, respectively. Succesful fabrication was achieved.

A new high-quantity in-line dc-magnetron sputter deposition metallization technique for the formation of grafted multilayer thin film modules was presented. The technique produced devices with high reliability and low defect levels and provided layered metal systems with either discrete or phased interfaces. When plasma optimization was used, deposit thickness variation over the deposition area was effectively controlled throughout the life of the targets.

The formation of surface CoSi2 layers was studied by moderate dose implantation of cobalt into silicon. There was a production of continuous layers of silicides with similar electrical properties from implants at room temperature and 355 degrees centigrade. The films were thermally stable up to 900 degrees centigrade with aminimum sheet resistivity of 9.2 ohms/square. The usefulness of this method haspractical application for self-aligned source-drain contacts in shallow junction complimentary metal-oxide-semiconductor technology due to its low leakage currents.

Electron spin resonance and photoluminescence studies of n-type GaN films reveal that conduction in these films results from a delocalized donor band. The studies, based on Van der Pauw-Hall measurements, are conducted on n-GaN films with AlN and GaN buffer layers and film thickness ranging from 0.5 to 10 microns. Test samples are grown using low pressure metal organic chemical vapor deposition techniques.

Ionic substances with melting points at or close to room temperature are referred to as ionic liquids. Interest in ionic liquids for their potential in different chemical processes is increasing, because they are environmentally benign and are good solvents for a wide range of both organic and inorganic materials. In this study, a capillary electrophoretic method for resolving phenolic compounds found in grape seed extracts is reported. The method, in which 1-alkyl-3-methylimidazolium-based ionic liquids are used as the running electrolytes, is simple and reproducible. The separation mechanism seems to involve association between the imidazolium cations and the polyphenols. The role of the alkyl substituents on the imidazolium cations was investigated and will be discussed.

Electronic systems that use rugged lightweight plastics potentially offer attractive characteristics (low-cost processing, mechanical flexibility, large area coverage, etc.) that are not easily achieved with established silicon technologies. This paper summarizes work that demonstrates many of these characteristics in a realistic system: organic active matrix backplane circuits (256 transistors) for large ([approximately equals] 5 x 5-inch) mechanically flexible sheets of electronic paper, an emerging type of display. The success of this effort relies on new or improved processing techniques and materials for plastic electronics, including methods for (i) rubber stamping (microcontact printing) high-resolution ([approximately equals] 1 [micro]m) circuits with low levels of defects and good registration over large areas, (ii) achieving low leakage with thin dielectrics deposited onto surfaces with relief, (iii) constructing high-performance organic transistors with bottom contact geometries, (iv) encapsulating these transistors, (v) depositing, in a repeatable way, organic semiconductors with uniform electrical characteristics over large areas, and (vi) low-temperature ([approximately equals] 100 [degrees] C) annealing to increase the on/off ratios of the transistors and to improve the uniformity of their characteristics. The sophistication and flexibility of the patterning procedures, high level of integration on plastic substrates, large area coverage, and good performance of the transistors are all important features of this work. We successfully integrate these circuits with microencapsulated electrophoretic 'inks' to form sheets of electronic paper.

Diamond-like carbon (DLC) coatings were deposited on [Al.sub.2][O.sub.3]-TiC substrate of head sliders by filtered cathodic arc (FCA), ion beam (IB), electron cyclotron resonance chemical vapor deposition (ECR-CVD) and sputtering (SP) with thicknesses of 5, 10 and 20 nm. Drag and CSS tests were performed using a commercial laser-textured disk. The interface failures, correlated to tribological properties of coatings on the head slider and disk surfaces, are discussed. The IB coatings show the longest interface durability whereas sputtered DLC coatings show the lowest interface durability. However, if DLC coatings on the head slider and disk surfaces are deposited with the compatible elastic modulus, based on mechanical characterization it is believed that FCA and ECR-CVD may also hold a promise for superior tribological performance. Index Terms--Deposition technique, diamond-like carbon, head-disk interface, tribology.

A unique electrophoretic method, nonequilibrium capillary electophoresis of equilibrium mixtures (NECEEM) is introduced. Classical affinity analyses often fail to work with lowaffinity complexes; NECEEM takes advantage of a rapidly decaying complex to calculate all equilibrium and kinetic parameters of the reaction in a single experiment.

Silicon carbide (SiC) is a wide-band gap semiconductor and one of the more promising materials for use in high-temperature high-power devices because of its thermal chemical, and mechanical stability. Still, [...]