This PDF file contains the front matter associated with SPIE Proceedings Volume 8816, including the Title Page, Copyright Information, Table of Contents, and the Conference Committee listing.

Extremely large-area roll-to-roll (R2R) manufacturing on flexible substrates is ubiquitous for applications such as paper and plastic processing. It combines the benefits of high speed and inexpensive substrates to deliver a commodity product at low cost. The challenge is to extend this approach to the realm of nanopatterning and realize similar benefits. In order to achieve low-cost nanopatterning, it is imperative to move toward high-speed imprinting, less complex tools, near zero waste of consumables, and low-cost substrates. We have developed a roll-based J-FIL process and applied it to a technology demonstrator tool, the LithoFlex 100, to fabricate large-area flexible bilayer wire-grid polarizers (WGPs) and high-performance WGPs on rigid glass substrates. Extinction ratios of better than 10,000 are obtained for the glass-based WGPs. Two simulation packages are also employed to understand the effects of pitch, aluminum thickness, and pattern defectivity on the optical performance of the WGP devices. It is determined that the WGPs can be influenced by both clear and opaque defects in the gratings; however, the defect densities are relaxed relative to the requirements of a high-density semiconductor device.

Drying process of polymer solution coated on a flat substrate is very important in various industrial applications. Then we have proposed and modified a model of drying process of polymer solution coated on a flat substrate for flat polymer film fabrication. In the previous study, we added Marangoni effect as pseudo-negative diffusion on an upper gas-liquid interface to the former model. And we saw through numerical simulation of the modified model that solute on upper gas-liquid interface was attracted more strongly to the edge due to Marangoni effect. In this study, we show that this effect is remarkable on upper gas-liquid interface, while the effect extends to sufficiently inside of the polymer solution film.

We report on electrically-driven diffraction grating, where refractive index of a liquid crystal (LC) was modulated periodically at an interval of 700 nm by applying an external DC bias to a metallic nanograting (NG). The LC-NG structure exhibited a maximum refractive index variation (Δn) of 0.088 and a diffraction efficiency (η) change of 0-16% with a large diffraction angle of 64° for incident light of 633 nm wavelength. This approach, with the help of faster electronics, provides an opportunity of developing active holograms for real 3D display

We demonstrated the optical microscope (OM) combined with nanopipette-based quartz tuning fork - atomic force microscope (QTF-AFM) for nanolithography. The nanoparticle (Au, 5 nm), nanowire, PDMS solutions are ejected onto the substrate through the nano/microaperture of the pulled pipette, and the nano/microscale objects were in-situ formed on the surface with the proposed patterning system, while the position is defined by monitoring the phenomena on the substrate with a home-made OM. After forming of capillary condensation between apex of the pipette tip and the surface, the electric field is applied to extract out the inside liquid to the substrate and the nano/microscale objects are fabricated. The nanoscale patterning size can be controlled by the aperture diameters of the pulled pipette.

Managing waste solvent is the most cost effective and environmentally friendly method. To reduce waste solvent, this investigation focused on the effect of the solvent ratio on the diameter of the spheres and on the structure of the photonic crystal by using recycled solvent. The sphere diameter reduced with the reduction of the NH4OH ratio. To investigate the effect of the recycled solvent on the structure of the silica spheres, the recycled solvent was repeatedly used five times. The diameter and shape of the silica spheres were similar when the solvent was used twice. However, the shape and structure of the spheres became more irregular with the increase of the recycling time. The FTIR spectra of all spheres are identical. To identify the cause of the irregular structure of the spheres, the solvent recycled five times was evaporated, and the residual compound was analyzed. As a result, the residual compound was composed of Si-O-Si and Si-OH. This residual silica compound may cause the connected and irregular structure of the spheres.

We report on characterization of Pd/ZnO nanostructure thin film Schottky contacts based UV photodetector. The ZnO film was grown on p-type Si ‹100› substrate by using vacuum thermal evaporation method. With applied voltage in the range from -2V to 2V we estimated the photocurrent, contrast-ratio, responsivity and quantum-efficiency of the photodetectors for an incident optical power of 0.1mW at 365nm ultraviolet wavelength. The I-V characteristics were studied and the parameters such as ideality-factor, leakage-current, and barrier-height of the Schottky contacts were extracted from the measured data. The surface morphological and the structural properties of the thin film were studied by atomic force microscope (AFM) and scanning electron microscopy (SEM). The bandgap of ZnO is evaluated from the absorbance spectra of ZnO thin film obtained by using double beam spectrophotometer. For the investigation of the surface chemical bonding, X-ray photoelectron spectroscopy (XPS) measurements were also performed. The device exhibited good stability, high efficiency and high sensitivity under the reverse bias condition. For forward bias, the UV detection sensitivity decreased proportionally to the bias voltage.

We present a comprehensive study of generation and collision of optical similaritons in sub-micron silicon photonic wire waveguides. Our analysis of optical pulse dynamics in such wave guiding devices is based on a rigorous theoretical model that incorporates all of the relevant linear and nonlinear optical effects, including modal dispersion, free-carrier dispersion and absorption, self-phase modulation, two-photon absorption, frequency dispersion of the optical nonlinearity, and the free-carrier dynamics. In addition to the particular characteristics of the generation of optical similaritons in silicon photonic wires, we also investigate the dependence of the efficiency of this optical process on the physical parameters and temporal profile of the input pulse. The collision of optical similaritons that propagate both in the normal and anomalous dispersion regime is also analyzed. Guided by the target applications of our study, we considered two technologically relevant spectral regions, namely, telecom and mid-IR frequency domains.

The use of Green’s functions to solve inhomogeneous differential equations, such as the Maxwell’s equations with source currents is well known. Unfortunately, it is usually difficult – if not impossible – to find a Green’s function which satisfies the boundary conditions. The finite difference time domain (FDTD) algorithm is derived from a finite difference equation (FDE) of Maxwell’s equations. FDTD, which automatically takes boundary conditions into account, is often used to solve the FDE, but its computational cost increases much faster than the accuracy as the grid spacing (h) decreases; moreover small h must be used to capture fine features of structures such as subwavelength gratings. A discrete Green’s function (DGF), computed using FDTD, can be used to overcome some of the shortcomings of FDTD alone. A DGF computed using FDTD automatically includes the boundary conditions of the problem. In this paper we use a DGF based on what is called a nonstandard finite difference model of Maxwell’s equations to compute scattering off subwavelength structures. We verify the accuracy of our method by comparing our calculations with analytic solutions given by Mie theory.

We investigate the influence of passivation structure on the optical mode distribution and LI characteristics for the edge emitting AlGaInP-GaInP visible laser diode (LD). For traditional single-layer Si₃N₄ or SiO₂ passivation designs, the modification of dielectric layer thickness can determinate the lateral near-field confinement and change the horizontal far-field (FF) divergence. By increasing the film thickness, the non-radiation absorption come from Au-Ti can be improved and it leads to a narrow FF divergence beam. As continue to increasing the thickness, thicker passivation provides a better confinement factor and then the far-field pattern turn to be wider. For LI characteristics, it is necessary to deposit a thick enough passivation to reduce metal absorption. However, it cause much thermal energy accumulated in the ridge waveguide and deteriorate the quantum efficiency as adopting a too thick dielectric layer. Finally, we demonstrate a high power AlGaInP-GaInP multi quantum wells (MQWs) LD adopted a high-reflectivity passivation to enhance the LI characteristics and keep a suitable far-field divergence angle simultaneously. Under the design of threepair optical thin films, it cannot only avoid the metal absorption but also enhance emitting efficiency and heat dissipation by using a high reflective and good thermal conductive Al₂O₃/Ta₂O₅ multilayer. The measured room-temperature threshold current (I_th) and characteristic temperature (T₀) can be arrived 44.5mA and 104.2K at 16.4° far-field divergence.

Recently, significant developments in evanescent wave absorption sensors have been demonstrated for high temperature sensing applications based upon the optical responses of advanced thin film materials. We will demonstrate how such sensors can be utilized in a mode that allows for chemical or temperature sensing starting from basic theoretical considerations. We will also present experimental high temperature sensing results for fabricated sensors. Potential applications of the sensors to be discussed include a range of high temperature systems relevant for fossil energy and combustion monitoring such as industrial combustors or reaction vessels, solid oxide fuel cells, and gas turbines. In these applications, even a small increase in operating efficiency realized via careful observation of in-process parameters and implementation of real-time process controls can result in dramatic savings across the energy industry, illustrating the necessity of pursuing such techniques. It is hoped that sensors of the type described here will allow for unprecedented measurement-access to processes which present challenging high-temperature and chemically reactive environments.

The effects of quantum efficiency on PbSe/Pb0.934Sr0.066 Se multiple Quantum well Structure were analyzed. We calculate and identify the critical design parameters required to optimize and study the MQW system as a function of five temperatures assuming the quantum efficiency is not equal to one and hence we include the effects of nonradiative recombination due to Auger recombination and carrier leakage over the barrier into the confinement layers. Inclusion of quantum efficiency in addition to temperature dependence increased the threshold current values by almost 10 times. Also, it was noticed that the threshold current density values dropped fast at small cavities and remained constant after some critical cavity length around 100 μm. When experimental quantum efficiency values were used, the threshold current values were higher than those found using the theoretical quantum efficiency values due to leakage current over the barrier.

Approximately two thirds of all fossil fuel used is lost as heat. Thermoelectric materials, which convert heat into electrical energy, may provide a solution to partially recover some of this lost energy. To date, most commercial thermoelectric materials are too inefficient to be a viable option for most waste heat applications. This research proposes to investigate the fabrication and characterization of nanostructured III-V semiconductor thermoelectric materials with the goal of increasing the performance of existing technology. In order to improve thermoelectric material efficiency, either the lattice thermal conductivity must be lowered or the thermoelectric power factor must be increased. This research will focus on the latter by modifying the density of states of the semiconductor material and studying the effect of quantum confinement on the material’s thermoelectric properties. Using focused ion beam milling, nanostructured cantilevers are fabricated from single crystal wafers. An all around gate dielectric and electrode are deposited to create a depletion region along the outer core of the cantilever, thus creating an inner conductive core. The Seebeck coefficient can then be measured as a function of confinement by varying the gate voltage. This technique can be applied to various material systems to investigate the effects of confinement on their thermoelectric properties.

The development of nanotechnology gives new possibilities for fabrication of high efficiency X-ray optical elements. The stacked multilevel crystal Zone Plate (ZP) is fabricated by means of high resolution negative tone inorganic HSQ (Hydrogen Silsesquioxane or XR-1541) electron-beam resist. About 80% of the HSQ resist became SiO₂ after electron beam lithography. This is a simple method to fabricate ZPs with SiO₂ masks. Stacked multilevel silicon ZPs consisting of bi-level zone profiles have been investigated. The composed multilevel ZP consists of two separate ZPs which have different structures. The distance between ZPs varied from 0mm up to 2mm. We recorded the maximal efficiency when the distance between ZPs varied from 0μm up to 150μm (about same efficiency). The efficiency of stacked multilevel crystal ZP has decreased when the distance between ZPs has varied from 0μm up to 2mm. The efficiency of the phase ZP is 40.5%. The maximum efficiency for bi-level ZP without absorption is 68.4%. We obtain theoretically 54.6% and experimentally 47% efficiency for the stacked bi-level ZP when the distance between ZPs was 0μm. The experimentally and theoretically investigations were done for x-ray energy at the 8 KeV and 12.4 KeV. The radial distribution of intensity is determined as a convolution of the zone plate transmission function and the Kirchhoff propagator in par-axial approximation. The algorithm is based on the FFT procedure and studied by means of computer programming simulation.

A new strategy to build large-scale solvent-responsive elastomeric opal films that are candidates for a wide range of optical sensor applications is reported. Hard-soft core-interlayer-shell (CIS) beads were used to prepare paper-supported elastomeric opal films with remarkably distinct iridescent reflection colors. Extrusion and compression molding of the CIS beads directly on the top of a highly porous paper sheet followed by UV cross-linking led to polymer-paper composite films with a high tensile strength and an outstanding solvent resistivity. Due to the high porosity of the paper sheets used, these composites could be easily swollen by various solvents. The swelling changed the crystalline lattice of the opals which provoked a tremendous photonic band gap shift and also enhanced the brilliance of these colors. After deswelling, the original opal structure was totally restored which means that the shift of the photonic band gap was completely reversible. This approach can become the basis for a whole family of polymer-based soft sensors with a fascinating optical response.

We propose a fabrication process using dielectrophoretic (DEP) force for plasmonic devices as a light source. The 100nm wide Au nanowires fabricated by e-beam lithography and lift-off were used to trap 25nm diameter cadmium selenide (CdSe) QDs on its end-facet with DEP force. DEP force was induced around the nanowire using 8 V_pp, 3MHz sine wave. An Electric field of 10⁸ V/m order and electric field gradient of 10¹⁵ V/m² order intensity were calculated with COMSOL multiphysics simulation tool. And the values are enough to induce DEP force for QD trapping. Before the QD manipulations, polystyrene bead was used which is more rigid and influenced by DEP force than QD. Concentration of 10^-5% order and approximately 120sec reaction time are considered with polystyrene bead and QD manipulations are accomplished with the conditions. Finally, the QDs were manipulated to the nanowires array and ‘QD on nanowire’ nanostructure was formed as a practical plasmonic device using DEP force.

The theoretical characteristics of photon emission at 1.55 μm wavelength are presented considering single layer of indium nitride (InN) quantum dots in the active region. The transparency threshold has been obtained at photon energy of 0.8016 eV and at zero normalized applied transition energy, respectively. The modal gain of about 12.5 cm^-1 is obtained at the threshold current density of 51 Acm^-2. The external differential quantum efficiency of 65% has been achieved for the cavity length of 640 μm. The proposed structure with acceptable enhanced results will create a way to fabricate InN based quantum dot laser.

We proposed a plasmonic-WGM hybrid system composed of a tapered-fiber-coupled microsphere resonator and a PICattached gold tip to focus the incident light into a nanoscale domain (~728.8 nm²) with high coupling efficiency of ~80.3 % and the Q factor of ~1.9×10⁶. In order to experimentally verify the strong interaction between light and matter owing to efficient excitation of localized surface plasmon at the gold-coated tip, we demonstrated to observe two-photon excited fluorescence from PIC dye molecules attached on the gold-coated tip even under a weak CW excitation condition via a tapered-fiber-coupled microsphere resonator.

A new generation of surface plasmonic optical fibre sensors is fabricated using multiple coatings deposited on a lapped section of a single mode fibre. Post-deposition UV laser irradiation using a phase mask produces a nano-scaled surface relief grating structure, resembling nano-wires. The overall length of the individual corrugations is approximately 14 μm with an average full width half maximum of 100 nm. Evidence is presented to show that these surface structures result from material compaction created by the silicon dioxide and germanium layers in the multi-layered coating and the surface topology is capable of supporting localised surface plasmons. The coating compaction induces a strain gradient into the D-shaped optical fibre that generates an asymmetric periodic refractive index profile which enhances the coupling of the light from the core of the fibre to plasmons on the surface of the coating. Experimental data are presented that show changes in spectral characteristics after UV processing and that the performance of the sensors increases from that of their pre-UV irradiation state. The enhanced performance is illustrated with regards to change in external refractive index and demonstrates high spectral sensitivities in gaseous and aqueous index regimes ranging up to 4000 nm/RIU for wavelength and 800 dB/RIU for intensity. The devices generate surface plasmons over a very large wavelength range, (visible to 2 μm) depending on the polarization state of the illuminating light.

Fabrication of nanostructures for applications such as plasmonics and metamaterials are typically accompanied by a slow production and limited area due to the required sub-micron feature sizes. In these applications, periodic array of metal/dielectric features can produce optical resonance responses such as optical field enhancement response, Fano response, chiral response, and negative refractive index. Here, we propose a mask-less photolithography technique that can produce a variety of periodic nanostructure clusters. The method is based on microsphere nanolithography, which focuses UV field into the so-called photonic jet which is a propagative intensive field underneath the sphere. The position of photonic jet can be moved by changing the angle of exposure. The method introduces a controllable scheme to realize nano-gap size by controlling the angle of exposure. The feature sizes generated by this method are about one third of exposure wavelength. The method is compatible with highthroughput nano-manufacturing schemes, such as roll-to-roll production. Here we present some examples to demonstrate the capabilities of this method in producing an array of complex plasmonic molecules over a large area. The periodicity of array and element’s diameter can be tuned by microsphere size and exposure/developing time, respectively. Tilted exposure lithography inherently is self-aligned and readily extendible to deep UV lithography due to absent of mask and optical elements. FDTD simulation agrees well with our experimental results, and suggests that much smaller feature sizes can be achieved at shorter wavelengths.

As the operating frequency of electromagnetic based devices increase, physical design geometry is playing an ever more important role. Evidence is considered in support of a relationship between the dimensionality of primitive geometric forms, such as transistors, and corresponding electromagnetic coupling efficiency. The industry of electronics is defined as the construction of devices by the patterning of primitive forms to physical materials. Examples are given to show the evolution of these primitives, down to nano scales, are requiring exacting geometry and three dimensional content. Consideration of microwave monolithic integrated circuits,(MMIC), photonics and metamaterials,(MM), support this trend and also add new requirements of strict geometric periodicity and multiplicity. Signature geometries,(SG), are characterized by distinctive attributes and examples are given. The transcendent form transcode algorithm, (TTA) is introduced as a multi dimensional SG and its use in designing photonic integrated circuits and metamaterials is discussed . A creative commons licensed research database, TRANSFORM, containing TTA geometries in OASIS file formats is described. An experimental methodology for using the database is given. Multidimensional SG and extraction of three dimensional cross sections as primitive forms is discussed as a foundation for quantum engineering and the exploitation of phenomena other than the electromagnetic.

Near-field scanning optical microscope (NSOM) lithography is one of optical technologies for planar structure fabrication, where exposure process is performed by optical near field produced at tip of fiber probe. Maskless exposure of defined regions is performed so that different periodic and predefined arrangement can be achieved. In this contribution, NSOM lithography is presented as effective tool for semiconductor device surface patterning. Non-contact mode of NSOM lithography was used to pattern planar predefined structures in GaAs, AlGaAs and GaP surfaces. In this way, GaAs/AlGaAs-based LED with patterned structure in the emitting surface was prepared, where patterned air holes show enhancement of radiation in comparison with the surrounding surface. Furthermore, NSOM in combination with lift-off technique was used to prepare metal-catalyst particles on GaP substrate for subsequent growth of GaP nanowires which can be used in photovoltaic applications.

Implementation of planar surface structures allows enhancement of light extraction from the light emitting diode (LED) surface due to diffraction-on-roughness based effect and photonic-band gap effect. Application of such structures can be attractive for overall and local enhancement of light from patterned areas of the LED surface. We used interference and near-field scanning optical microscope lithography for patterning of the surface of GaAs/AlGaAs based LEDs emitted at 840 nm. Also new approach with patterned polydimethylsiloxane (PDMS) membrane applied directly in the LED surface was investigated. Technology of patterned PDMS membranes using interference lithography and imprinting process was developed. The overall emission properties of prepared LED with patterned structure show enhanced light extraction efficiency, what was documented from near- and far-field measurements.

Nanostencil Lithography (NStL), while comparatively still in infant stages, is proving to be a viable option for low-cost and high resolution fabrication. An ideal stencil for NStL consists of a low-stressed silicon nitride membrane supported on a silicon chip with required patterned features in nanometer range that become apertures. The stencil is used as a shadow mask and placed in close contact on top of a substrate/wafer. This pair is then ready for either depositing metal through the apertures in the stencil using variety of deposition techniques or etching the substrate using dry etching techniques with stencil acting as a mask. The nanostencils were fabricated using focused ion beam writing on a silicon nitride window/membrane. We made well-ordered array of 700 nm diameter and 15 nm thick gold and chromium nanodots on III-V substrate. Metal layers were deposited using e-beam evaporator. The formed gold nanodots can be used for vapor-liquid-solid nanowire growth (bottom-up), while the chromium nanodots were used as a mask for reactive ion etching of GaAs structures, for instance, fabricating nanowires (top-down approach). We used the nanostencil directly as a mask for dry etching of InP substrate for making nanoholes array. Making these types of nanoholes in silicon oxide layer deposited on the top of III-V substrate opens the possibility to use in selective area growth of nanowires. Additionally, we fabricated optical nanoantenna structures to demonstrate other possible usage of NStL.

The paper describes the preparation of polydimethylsiloxane (PDMS) fiber integrated on the conventional optical fibers and their use for optical fiber displacement sensor. PDMS fiber was made of silicone elastomer Sylgard 184 (Dow Corning) by drawing from partially cured silicone. Optical fiber displacement sensor using PDMS fiber is based on the measurement of the local minimum of optical signal in visible spectral range generated by intermodal interference of circularly symmetric modes. Position of the local minimum in spectral range varies by stretching the PDMS fiber of 230 μm in the wavelength range from 688 to 477 nm. In the stretched PDMS fiber is possible to determine the longitudinal displacement with an accuracy of approximately 1 micrometer.

We investigated optical properties of subwavelength patterned metal gratings for photonic device application. It was known that optical transmittance of metal films with subwavelength periodic hole arrays can be controlled by applying a dielectric overlay to the film and the films can act as wavelength or frequency selective filters. Following advancement in lithography technology it could be applied up to complementary metal oxide semiconductor (CMOS) image sensors (CIS) by patterning metal layers placed on each pixel’s photo detective device. However it is not easy to replace organic color filters applied on CIS up to date because the standard CIS structure has multi-metal layers, thick dielectric layers, and too thick metal layers. In this work, we explore possibility to integrate the metal film into a CIS chip and present an alternative proposal by computer simulation utilizing finite-difference time-domain (FDTD) method. We applied aluminum (Al) for the metal film and the dispersion information associated with Al was derived from the Lorentz-Drude model. We expect that this work could contribute to search to apply subwavelength patterned metal gratings to photonic devices.

Titanium dioxide (TiO₂) has been draw attention for wide range of applications from photonic crystals for visible light range by its catalytic characteristics to tera-hertz range by its high refractive index. We present an experimental study of fabrication of fine structures of TiO₂ with a ZEP electron beam resist mask followed by Ti sputter deposition techniques. A TiO₂ thin layer of 150 nm thick was grown on an FTO glass substrate with a fine patterned ZEP resist mask by a conventional RF magnetron sputter method with Ti target. The deposition was carried out with argon-oxygen gases at a pressure of 5.0 x 10 ^-1 Pa in a chamber. During the deposition, ratio of Ar-O₂ gas was kept to the ratio of 2:1 and the deposition ratio was around 0.5 Å/s to ensure enough oxygen to form TiO₂ and low temperature to avoid deformation of fine pattern of the ZPU resist mask. Deposited TiO₂ layers are white-transparent, amorphous, and those roughnesses are around 7 nm. Fabricated TiO₂ PCs have wider TiO₂ slabs of 112 nm width leaving periodic 410 x 410 nm² air gaps. We also studied transformation of TiO₂ layers and TiO₂ fine structures by baking at 500 °C. XRD measurement for TiO₂ shows that the amorphous TiO2 transforms to rutile and anatase forms by the baking while keeping the same profile of the fine structures. Our fabrication method can be one of a promising technique to optic devices on researches and industrial area.

Optical metasurfaces demonstrate outstanding capabilities of optical parameters modifications by changes in the structural architecture at the nano-scale level. We demonstrate results of electrophoretic experiments that modify the structure of a metasurface by using diamond nanoparticles with sizes much smaller than the wavelength of light; the nanoparticles are suspended in an aqueous solution and a uniform electric field is applied. The electric field controls the concentration of nanoparticles inside the sub-wavelength apertures and on the top plane of the metasurface. The higher concentration of diamond nanoparticles increases the refractive index of the suspension as well as increasing scattering and absorption. Results of optical material parameter characterization for a wavelength of 512 nm are provided for different concentrations of the diamond nanoparticles dispersions.

In this work, we investigated the diffraction of inverse-hemisphere shaped polymer grating. We fabricated an inverse-hemisphere- shaped grating structure using soft lithography of close-packed PS nanospheres that is easy and cost-effective method. Then the diffraction wavelength shift induced from lattice change was measured. The periodicity of the grating was tuned by swelling in acetone. The measurement results suggest that the device can be used as a strain gauge or a chemical sensor.

In this works, the piezoelectric devices of ZnO nano-rods were fabricated for piezoelectric sensor. The ZnO nano-rods were grown by hydrothermal synthesis through two-dimensional nano-patterns using a laser interference lithography. ZnO nano-rods were preferred orientation with c-axis and wurtzite structure. It was found that the electricity of nano-rod piezoelectric device was 8x10^-7 Wh under the load of 0.8kgf. The piezoelectric behaviors are attributed to the direct compression of ZnO nano-rods by an external force. Therefore, the piezoelectric devices of ZnO nano-rods fabricated by hydrothermal methods were applicable to the pressure sensors.

The conventional wisdom to guarantee high purity thin films in IBSD has been to use a large vacuum chamber usually in excess of 1 m³. The chamber size was important to minimise the effect of reflected high energy particles from the target surface sputtering chamber materials onto the substrate and to allow the use of large targets to avoid beam overspill onto chamber furniture. An improved understanding of beam trajectories and re-sputtered material paths has allowed the deposition of thin films with very low metallic impurity content in a chamber volume below 0.5 m³. Thus, by optimizing the sputter ion source, target and substrate configuration, and by arranging suitable shielding made of an appropriate material in the process chamber, the levels of contaminants in the deposited films have been reduced to a minimum. With this optimum hardware arrangement, the ion beam process parameters were then optimized with respect to the ppm levels of contaminants measured in the films by SIMS analysis. Using the deposition of SiO₂ as a standard material for DSIMS composition analysis and impurity level determination, it has been shown that our IBS deposition tool is capable of depositing films with contamination levels of <50ppm for the total of all metal impurities in the deposited films.

In this paper, we demonstrated the fabrication of laser-induced holes in the gold film of 50nm thickness using 120fs laser pulses at 800nm wavelength in air environment. The surface morphologies¬microstructures and diameters of holes were characterized using atomic force microscopy (AFM). It was found that, there are two kinds of thresholds of laser fluence for the formation of holes. And the diameters of holes were influenced by pulse energy and shot numbers. Based on the investigation above, the origin of the holes was discussed.