Effects of Al-concentration on growth of antiphase domains (APDs) in Ti3Al crystals have been investigated using crystals with stoichiometric (Ti-25at.%Al) and Al-rich (Ti-33at.%Al) compositions in the temperature range from 973K to 1173K. The growth rate of APDs in the Al-rich crystal is several times higher than that in the stoichiometric crystals at all the temperatures investigated. While the time dependence of APD size obeys the parabolic-growth-law in the stoichiometric crystal, negative deviations from the law takes place at the late stage of the APD growth in the Al-rich crystal owing to the pinning effect of low-energy APB boundaries. APD boundaries lying on prism planes are formed in the Al-rich crystal annealed at 973K.

We describe a new approach for biomaterial patterning, viz, masked ion beam lithography. Poly (methyl methacrylate) (PMMA) film was used as a model system and subjected to Ca+ and P+ ion implantations through masks. Ca+ ion implantation was performed at an energy of 85 keV with a fluence of 1×1014 ions/cm2. P+ ion implantation was done at an energy of 85 keV with fluences of 1×1015 and 1×1016 ions/cm2. Arrays of holes were generated during these processes. AFM showed that the depth of the holes is in the nanoscale region. The surface hydrophobicity of the exposed PMMA films was investigated by contact angle measurement. The results indicated that ion implantation changed the surface hydrophobicity.

The extendability of conventional subtractive lithographic processing using spin-coated polymeric single layer resists (SLR) faces many challenges as feature sizes in microelectronics push below 100 nm. In addition, the opacity of the polymeric materials traditionally used as SLR resins to future exposure sources presents new challenges as the radiation penetration depth decreases (e.g. 157 nm, EUVL, low keV e-beam). One solution to these problems is the use of surface imaging materials and processes. In such surface imaging methods, exposure in only a thin surface layer is used to create a pattern in a substantially thicker etch barrier layer. Conventional surface imaging approaches have mainly focused on silylation techniques which have experienced a variety of problems. This paper presents an update on two novel surface imaging methods under investigation: (1) surface monolayer initiated polymerization (SMIP) and (2) organometallic-organic bilayer resists.

The SMIP process involves using a monolayer that contains a polymerization initiator functionality. Exposure of the monolayer to radiation can deactivate the initiators in selected areas and the remaining initiators can subsequently be used to directly grow patterned polymer structures. This process allows complete decoupling of the imaging properties of the monolayer from the etch properties of the polymer etch barrier. In essence, the polymerization process is used to amplify the pattern initially formed in the monolayer. Recent results are presented that demonstrate the use of x-ray photoelectron spectroscopy in conjunction with dose array experiments to analyze the sensitivity of the initiators used for this process.

The other novel surface imaging method presented in this work uses organometallic-organic bilayers. In these systems, thin films of radiation sensitive organometallic precursors are used as an imaging layer in conjunction with thick organic etch barrier layers. Upon exposure, the organometallic precursor film is selectively converted to metal oxide. After exposure, the unexposed regions of the film can be developed away. Subsequent dry pattern transfer in an oxygen plasma can be used to transfer the pattern defined in the thin oxide layer through the organic etch barrier layer. Organometallic precursor films with sensitivities on the order of 70 μC/cm2 are demonstrated which result in oxide films that possess an etch selectivity of 100:1 with respect to novolac in oxygen plasmas. 500 nm line-space patterns are demonstrated as a first lithographic imaging proof-of-concept.

We propose a method for replicating patterns with a resolution well below the diffraction limit, using broad beam illumination and standard photoresist. In particular it is shown that visible exposure (λ=410 nm) of silver nanoparticles in close proximity to a thin film of g-line resist (AZ 1813) can produce selectively exposed areas with a diameter smaller than λ/20. The technique relies on the local field enhancement around metal nanostructures when illuminated at the surface plasmon resonance frequency. The method can be extended to various metals, photosensitive layers, and particle shapes.

Co/Pt thin film multilayers with strong perpendicular anisotropy and out-of-plane coercivities of 5-11 kOe were magnetically altered in areas of local ion beam interaction. The ion irradiations were performed by ion projection through silicon stencil masks fabricated by silicon on insulator (SOI) membrane technology. The ion projector at the Fraunhofer Institute for Silicon Technology (ISiT) was operated at 73 keV ion energy and with a 8.7- fold demagnification. After exposure to 3 × 1014Ar+/ cm2 magnetic islands smaller than 100 nm in diameter were resolved in the Co/Pt multilayersby means of magnetic force microscopy. The impact of different ion species (He+, Ar+ and Xe+) and ion energies (10 – 200 keV) on the multilayer structure was evaluated using Monte Carlo simulations. The ballistic interface intermixing was used to predict magnetic coercivity changes for various irradiation conditions. The simulations revealed that with 73 keV Ar+ and Xe+ ions the irradiation dose could be reduced by a factor of 100 and 400 respectively in comparison to 73 keV He+which was verified in the experiments. X-ray reflectivity measurements confirmed that the Co/Pt superlattice structure is slightly weakened during the irradiation and that the surface smoothness of the media is preserved. Using the Ion Projection Process Development Tool (PDT) at IMS-Vienna concentric data tracks including head positioning servo informations were patterned onto a 1” IBM microdrive™ glass disk which was coated with Co/Pt multilayers. In a single exposure step several tracks within an exposure field of 17 mm in diameter were structured by 2 × 1015He+/ cm2 at 45 keV using a 4- fold demagnification set-up.

Three fundamentally different methods were used to fabricate nanometric surface features on polymers or fused silica. Phase separation of binary polymer mixes resulted in randomly distributed features whose depth and shape could be tightly controlled over large areas. Colloidal resist patterned large areas randomly and uniformly with very fine spikes. In contrast e-beam and reactive ion etching were used to create a set of regular spaced pillars on an orthogonal pattern. Some of the surfaces were replicated by in situ polymerization, solvent casting, embossing or melt molding onto polystyrene (PS) or ε–poly caprolactone (ε–PCL). Nanometric features down to 60nm were imprinted onto the polymers with high fidelity. Cells were seeded onto the nanometric surfaces and adhesion, morphology and cytoskeleton investigated. Cells respond to regular features of 170/80nm (width/depth) with reduced adhesion and changes in overall morphology and cytoskeleton. Small nanofeatures (13nm, 35nm depth) made by phase separation on the other hand increased adhesion and promoted cytoskeletal differentiation. The responses of the cells are indicative that nanometric surface features are useful modifications on scaffolds for tissue engineering or on medical implants.

The consequences of surface functionalization by grafting molecules like hydroxysilane, chlorosilane, and hexamethyldisilazane (HMDS) are reviewed for different types of nanoparticles including Si3N4, TiO2, and SnO2. Fourier transform infrared spectrometry is used as primary investigation tool. In terms of physical properties, these surface chemical modifications lead to improvements of the ion-sensitive FET and gas sensors characteristics. The beneficial effect of hydroxy- and chlorosilane grafted on Si3N4 used as ion sensitive membranes will be demonstrated. Then, the reduction of humidity effects on HMDS-grafted TiO2 and SnO2 nanosized powders used for screen-printed CO sensors will be reported.

Fullerite nanotubules of 100 nm to 2 μm radius, up to 200 nm wal thickness and 10 μm length were produced inside etched swift heavy ion tracks in a polymer, by letting fullerence precipitate from a concentrated C60 solution within the tracks. After contacting the tubules on both sides with silver paste, their resistivity was measured as a function of temperature. All of the 13 prepared samples show a complex behaviour that can be described by tw Arrhenius curves, the low temperature branch with activation energy Eact = (1.77 ± 0.2) eV stemming from pure C60, and the high temperature branch being tentatively ascribed to C60Agx with x ≍ 12.4 and Eact = (0.68 ± 0.2) eV, as the letter compound has found to be produced at ambient temperature by C60 / Ag thermal intermixture. Such samples with tw branches of negative temperature coefficients of resistance might be useful to construct advanced thermoresistors.

Currently, the microlithography industry creates large amounts of organic and aqueous wastes in the production of semiconductors. Using carbon dioxide can possibly eliminate the majority of these waste solvents as well as eliminate the image collapse problems shown with aqueous base development. We will discuss the use of carbon dioxide to replace the most solvent intensive steps of the microlithography process, spin coating, developing, and stripping. However, before CO2 can replace conventional solvents, photoresist systems must be designed and synthesized to be compatible with CO2. These photoresist systems must be soluble in liquid CO2 to insure that thin-uniform coatings can be produced by spin coating while maintaining characteristics of conventional resist systems such as low absorbance, high sensitivity, solubility contrast, good resolution, and etch resistance. Using our CO2 compatible resist system, we will demonstrate the ability of CO2 to spin coat uniform thin-films which (after exposing and PEB) can be developed using scCO2 to produce lithography features that may be stripped in CO2. Thus, revealing the enormous potential of CO2 to provide the microlithography industry an opportunity to escape its water and organic solvent dependence as it moves toward 157nm lithography.

The advent of polymer electrolytes has provided a promising route to an all solid-state polymer battery. Such a battery would have greater safety, without potential discharge of liquid or gel electrolyte. Current battery configurations typically involve a metal anode, a solvent-plasticized polyelectrolyte, such as poly (ethylene oxide) (PEO), and a composite cathode. We have synthesized an A/B/C triblock copolymer which could have potential use as an all-solid state nanoscale polymer lithium battery. The polymeric battery was synthesized with an anode, electrolyte and cathode by synthesizing an A/B/C triblock copolymer whose microphase separation would form lamellar domains. These nanodomains contain cobalt oxide, a derivative of PEO synthesized by ring opening metathesis polymerization, and a spinel phase LiMn2O4 as the anode, electrolyte and cathode material, respectively. The first block contains cobalt oxide that stores lithium ion in a novel electrochemical reaction that allows use in a battery configuration. The second block is polyethylene oxide derived from an unsaturated crown ether, and is used for its high ionic conductivity. The third block contains LiMn2O4, which is currently being investigated as a potential cathode material because of its low toxicity and ease of preparation. The nanometer size domains in the battery can be used in unique applications in microelectronics. In addition, such size scale allows use of the battery in discrete circuits, reducing the amount of wiring necessary in conventional battery configurations.

Accurate placement of biomaterials at nanoscale resolution opens new capabilities for biological sensing, cell manipulation, and control of cellular transduction cascades. We demonstrate that lipid molecules can be patterned on silicon using a polymer lift-off technique. Patterned lipid bilayers serve as biomaterial patterning platforms useful for studies of cellular function. Submicron feature sizes were achieved using this templating technique which is suitable for delicate biomaterials1. Projection lithography and reactive ion etching were used to pattern a Parylene-coated surface. The patterned surface was subsequently exposed to 100 nm unilamellar lipid vesicles that bound to the native oxide surfaces of silicon and spread to form supported lipid bilayers. The nanoscale pattern is realized as the polymer is peeled away in deionized water. The versatility of this method is demonstrated by the successful preparation of functionalized lipid bilayer surfaces. Specific intermolecular interactions were demonstrated between supported membranes: DPPE-PE (2000) biotin/avidin, dinitrophenol (DNP)-conjugated lipids/anti-DNP IgE, and cationic lipid and M13 dsDNA:YOYO-1.

By confining a polymer film between two electrodes one of which is solid but thin enough to be flexible, a characteristic lateral morphology is produced when a strong electric field is applied across the film. A simple model to describe the observed behaviour is presented which accounts for the length scales of the observed morphology. This model demonstrates that feature sizes ranging from microns to nanometers can be obtained through selective choice of key parameters.

Nature assembles nano-scale components using molecular recognition. In the case of DNA, hydrogen bonding is the driving force behind the matching of complementary pairs of single-stranded (SS) DNA to hybridize into a double strand of helical DNA. For the case of antibodies/antigens and ligands/receptors, binding takes places by a combination of electrostatic forces, chemical bonding, and shape mediated effects. In this project, the assembly of micron sized and smaller particles using biologically inspired events such as DNA hybridization and interactions of ligands and receptors is being investigated. Following the case of DNA, a single strand sequence can be attached to the device surfaces, which is complementary to a single strand sequence previously attached to a patterned surface. Using the natural hybridization of DNA, the devices are expected to assemble in solution as designed onto the substrate surface. Single strands of DNA can be used to provide charge on the devices so that long-range electrostatic forces may be used to bring the devices close to the assembly site. We have also used a less complex molecule to add negative charges to the particles allowing them to be guided into place using electric fields. Attachment of these molecules to surfaces is a critical step in the assembly process. Various factors affecting the attachment are being investigated and will be reported. These include sample preparation and conditions for attachment. We have used polystyrene beads as test objects and optimized the capture of the beads using DNA and Avidin/Biotin interactions. When successful, this approach can be used to assemble micro and nano-scale electronic circuitry including heterogeneous integration of materials. Y6.5.1

A method of aligning small amounts of colloidal particles between narrowly spaced electrodes using a combination of conventional nanofabrication and self-assembled monolayers has been developed. Transport measurements were performed on several devices

This paper describes stable, high sensitivity (5-10 μC/cm2 at 50 kV) e-beam resist systems utilizing chemical amplification suitable for mask fabrication for device generations below 100 nm. In particular, two resist systems with improved performance for mask fabrication developed in a joint program by Etec, IBM and Shipley will be described: a Si- doped version of the IBM KRS-XE resist (now commercially available) developed at IBM Research, and a new MANA resist developed at Shipley. Commercialization issues for mask e-beam resists also will be discussed.

The control of nanoholes formed by anodic oxidation of aluminum (Al) was investigated using AFM nano-indentation on Al film prior to the anodic oxidation. It is well known that ordered trigonal nanohole arrays are formed under certain voltage conditions of anodic oxidation of Al. We succeeded in forming both tetragonal and trigonal arrays of alumina nanoholes on a SiO2/Si- substrate by using nano-indentation on the surface of sputtered pure Al film. The ordered array of nanoholes was obtained at indentation intervals that were close to the nearest neighbor distance of nanoholes in the self-organization condition. Furthermore, we fabricated tetragonal and hexagonal Al nanodot arrays by the selective removal of porous alumina film.

In this study, we report on the development of a μCP technique, where the ink used on the surface of the stamp is made of aminopropyl trimethoxy silane (APTMS). The stamps for the μCP are prepared by polymerizing polydimethylsiloxane (PDMS) on photolithographically defined masters. Si wafers were used as the substrate on which a self assembled layer of APTMS was formed at the contact regions of the stamp. The regions of contact were subsequently used for the deposition of gold coated magnetite nanoparticles, resulting in 2D patterned metallic surfaces. The colloidal particles were analyzed by TEM and XRD, and the printed substrates were characterized by AFM.

The electrical properties of single dangling bonds on the Si(100)2×1:H surface are investigated by ultra high vacuum scanning tunneling microscopy. On the N-type Si(100)2×1:H surface, single dangling bonds created by feedback controlled lithography and natural dangling bonds have a fixed negative charge. On the other hand, they are observed as neutral on the P-type Si(100)2×1:H surface. Current image tunneling spectroscopy is used to characterize both types of dangling bonds. The dangling bonds with fixed negative charge display a dramatic voltage dependence with Friedel oscillations observed in the empty state images. The neutral dangling bonds appear as protrusions in both the empty and filled state images.

The use of vesicles as amplifiers in biosensors is receiving increasing attention. Because vesicles may entrap thousands of reporter molecules, strong signal amplification can be obtained if a small number of analytes can simply release the entrapped reporters. Surface immobilization of vesicles with sensitivities for different analytes could then provide for simultaneous amplified detection of a number of analytes on a single chip. To achieve this goal, vesicles must first be stably adsorbed to a surface, without rupture. We have varied vesicle composition and charge (phosphatidylcholine, phosphatidylcholine-phosphatidic acid at 4.6 molar ratio) and solution ionic strength, to study the adsorption of fluorescent vesicles to glass, gold, and gold modified with chemisorbed acetylcysteine. Surfaces were characterized with angle-resolved X-ray photoelectron spectroscopy (ARXPS), and vesicle integrity and behavior was studied using entrapped and lipophilic fluorescent markers either together or in separate experiments. Diffusion coefficients (by photobleaching recovery) and vesicle fusion (by energy transfer) were monitored using confocal fluorescence microscopy. Finally, as a “proof of principle”, release of a self-quenching entrapped reporter dye (calcein) by the detergent Triton X-100 was followed in real time.

Sub-micrometer copper nanostructures were deposited on p-type silicon (p-Si) by means of a selective electrochemical reaction. Ga+-ions from a focused ion beam (FIB) were used to 'write' damage patterns on p-Si; in a subsequent electrochemical reaction Cu was deposited selectively at these defect sites. So far we have been able to obtain Cu structures with a lateral resolution of 300nm, which is also the limit of the FIB currently used.

The process may offer advantages over traditional lithographic methods for producing nanometer sized metal structure on Si as no masking steps are required. Also, structures with a lateral resolution in the sub- 100nm region seem possible; so far the process has only been limited by the FIB's lateral resolution.