Showing papers on "Fabrication published in 1994"

VLSI fabrication principles : silicon and gallium arsenide

Abstract: Material Properties. Phase Diagrams and Solid Solubility. Crystal Growth and Doping. Diffusion. Epitaxy. Ion Implantation. Native Films. Deposited Films. Etching and Cleaning. Lithographic Processes. Device and Circuit Fabrication. Appendix. Index.

Cold Plasma in Materials Fabrication: From Fundamentals to Applications

Abstract: Development of Barrier Coatings for Cellulosic-basic Materials by Cold Plasma MethodsPlasma Processing of MaterialsFunctional Properties of Bio-inspired SurfacesThe Journal of the Korean Physical SocietyModeling of Neutral Gas Dynamics in High Density PlasmasCold Plasma in Food and AgriculturePlasma Technologies for TextilesIssues in Materials and Manufacturing Research: 2011 EditionReactivity Studies of Plasma-synthesized Aluminum Trifluoride and Electrochemical Synthesis of Non-stoichiometric Silver Selenide Nanowire ArrarysNon-Thermal Plasma Technology for Polymeric MaterialsSymposium and School on High-Resolution Molecular SpectroscopyPlasma Medical ScienceAnnual Review of Materials ResearchThin Films and NanostructuresPlasma CatalysisPlasma-enhanced Synthesis of Surfaces that Kill Bacteria on ContactNew Technologies for Fabricating Biological MicroarraysComprehensive Materials ProcessingSurface Science ReportsPlasma Induced Surface Modifiction of Lignocellulosic and Synthetic PolymersPlasma Surface Modification and Hydrophobic Barrier Coating of PaperElectrical Properties of Surface-modified Silicon NanomembranesNuclear Science AbstractsRomanian Reports in PhysicsPlasma Physics and EngineeringSubstrate-free Gas-phase Synthesis of GraphenePlasma Synthesis of High Surface Area Aluminum TrifluorideJournal of Natural Sciences and MathematicsPlasma-enhanced Deposition of Antifouling Layers on Silicone Rubber SurfacesInfluence of Low Atmospheric Pressure Plasma on Surface Modification of Phenolic Bonded Aspen FiberboardTextile Chemist and Colorist & American Dyestuff ReporterDesign, Fabrication, and Characterization of Photonic DevicesCold Plasma Materials FabricationSME Technical PaperNuclear Science AbstractsEuropean Physical JournalCold-plasma Synthesis of Poly (ethelene Glycol)-like Thin Films of Stainless Steel to Inhibit Bacterial Attachment and Biofilm FormationEuromat 99, Materials for Medical EngineeringMaterials WorldSurface Modification Technologies IX

Fabrication of continuous-relief micro-optical elements by direct laser writing in photoresists

Abstract: A laser writing system for the fabrication of continuous-relief micro-optical elements in photoresist is described. The technology enables a wide range of planar micro-optical elements to be fabricated and replicated into polymer film using Ni shims electroformed from the photo-resist originals. The advantages and limitations of laser writing technology for micro-optics fabrication are discussed. Examples of fabricated micro-optical elements include Fresnel microlenses and microlens arrays, kinoforms, and other continuous-relief phase elements.

Electrostatically driven vacuum-encapsulated polysilicon resonators Part I. Design and fabrication

Abstract: Basic design issues and a fabrication process based on surface-micromachining techniques for electrostatically driven vacuum-encapsulated polysilicon resonators are presented. A novel freeze-drying method that does not require vacuum equipment is presented. Reactive sealing with LPCVD silicon nitride is used to create the evacuated cavity, resulting in cavity pressures close to the deposition pressure. Design issues regarding choice of materials, technology and layout are discussed. First experimental results, including an admittance plot of the one-port resonator and a plot indicating the dependence of the Q-factor on the resonator geometry and ambient pressure, are presented.

A method to increase contaminant tolerance in protein matrix‐assisted laser desorption/ionization by the fabrication of thin protein‐doped polycrystalline films

Abstract: This paper describes the fabrication and use of thin polycrystalline films in matrix-assisted laser desorption experiments. These films consist of microcrystals of protein-doped matrix (crystal dimensions ⩽ 1 μm). The films produce intense protein-ion currents and can be grown in the presence of high concentrations of involatile solvents (e.g., glycerol, 6 M urea) without any purification. They strongly adhere to the substrate, allowing easier washing of the film, compared to dried-droplet deposits. The films are also more uniform than dried-droplet deposits, with respect to ion production. It is suggested that matrix-assisted laser desorption/ionization samples are composed of nonlinear optical devices that function as polymer ion-current sources. These devices (protein-doped matrix crystals) can be designed and fabricated in many forms to serve the special functions required by the analytical scientist.

Recent development in the fabrication of metal matrix-particulate composites using powder metallurgy techniques

Abstract: It is advantageous to fabricate metal matrix-particulate composites (MMPCs) using powder metallurgy (PM) because the fabricated composites possess a higher dislocation density, a small sub-grain size and limited segregation of particles, which, when combined, result in superior mechanical properties. The various PM-related processes currently in use in the fabrication of MMPCs, are reviewed, outlining the common problems encountered in each of these fabrication processes. The more recently developed PM techniques to fabricate MMPCs are also discussed.

Method for fabrication of high vertical aspect ratio thin film structures

Abstract: This invention relates to the area of microelectromechanical systems in which electronic circuits and mechanical devices are integrated on the same silicon chip. The method taught herein allows the fabrication of thin film structures in excess of 150 microns in height using thin film deposition processes. Wafers may be employed as reusable molds for efficient production of such structures.

Polycrystalline silicon-germanium thin-film transistors

Abstract: The fabrication of p- and n-channel MOS thin-film transistors (TFT's) in polycrystalline silicon-germanium (poly-Si/sub 1-x/Ge/sub x/) films is described, and their electrical characteristics are presented. Various technological issues are then addressed in order to provide direction for further work in optimizing the fabrication process. The initial devices fabricated in this work exhibit well behaved electrical characteristics; enhanced performance is expected to accompany improvements in the crystallization and defect-passivation processes. Compared to a poly-Si TFT technology, an optimized poly-Si/sub 1-x/Ge/sub x/ TFT technology may ultimately be able to provide a lower-temperature, shorter-time processing capability at little expense to device performance and it is therefore promising for large-area electronics applications. >

Fabrication of Vertical and Uniform-Size Porous InP Structure by Electrochemical Anodization

Abstract: A vertical porous InP structure with an aspect ratio larger than 100 was obtained by electrochemical anodization of a A-oriented n-InP substrate with HCl etchant. The photoluminescence spectrum of this porous InP showed less surface recombination as well as a slight blue shift attributed to the quantum-size effect. By initiating the etching through SiO2-defined mask windows, which were prepared by electron-beam direct writing along 3 crystalline directions, a uniformly sized (around 72% within the permissible fluctuation error of about 4 nm against 100-nm-sized triangles), high-density (around 50%) structure was fabricated for the first time. These results reveal that this process is very attractive for the fabrication of high-density and low-size-fluctuation quantum-wire and -box structures.

A silicon condenser microphone using bond and etch-back technology

Abstract: A new technology for the fabrication of condenser microphones in silicon has been developed. Bond and etch-back techniques and surface micromachining of monocrystalline silicon allow for a highly simplified process. The fabrication process has been applie

Multi-level conductor process in VLSI fabrication utilizing an air bridge

Abstract: This invention deals with the formation of the multi-level electrode metal structure and the interconnecting inter-level metal studs used in the fabrication of VLSI circuits. After the metal layers have been formed the inter-level dielectric material used in forming the structure is etched away leaving an air dielectric between the levels. The electrode metal and the inter-level metal studs are coated with a thin envelope oxide and the entire structure is covered with a passivation layer using material with a poor step coverage. The structure of this invention provides reduced parasitic capacitance, better step coverage in interconnecting layers, and improved circuit performance.

System and method for monitoring and evaluating semiconductor wafer fabrication

Abstract: A system (60) and method for monitoring, evaluating and controlling the uniformity of a semiconductor wafer fabrication process is provided for use in manufacturing integrated circuits on semiconductor wafers (40). By using in situ ellipsometry (20) in conjunction with statistical modeling methods, the spatial etch rate pattern across a semiconductor wafer (40) may be inferred as a function of the process conditions. A predicted mean etch rate may be calculated for other locations (46 and 48) on the semiconductor wafer surface (42) by using the mean etch rate measured at the selected ellipsometer site (44) and individual spatial etch rate models developed for each site (44 and 48) based on statistically designed experiments. The predicted mean etch rate at the other sites (46 and 48) is also a function of the fabrication process conditions. The method for evaluating uniformity may be used with fabrication processes such as oxidation, doping, etching or any other process which may be measured in situ at a selected location (44) on a semiconductor wafer (40) during the fabrication process.

Design and fabrication of monolithic optical spot size transformers (MOSTs) for highly efficient fiber-chip coupling

Abstract: A novel type of monolithic optical spot size transformer realized in the InP/InGaAsP material system combines many desirable features like high fiber-chip coupling efficiency, large spot size transformation, high tolerances for fiber alignment, simple fabrication, and straightforward integrability with other devices. The spot size transformation is accomplished by two waveguide sections tapered in the vertical and lateral directions, respectively. We discuss design issues, describe the fabrication process, give experimental results, and present the monolithic integration of the spot size transformers with a current controlled directional coupler switch. >

Deposition of silicon dioxide films using the helicon diffusion reactor for integrated optics applications

Abstract: Existing optical fibre and fibre-device fabrication techniques have been complemented recently by the development of new processes for the fabrication of planar optical waveguides and devices. These processes rely on new forms of plasma reactors and diagnostic systems which allow in-situ control of optical parameters such as refractive index. These plasma processing systems allow the fabrication of optical devices which are not readily feasible in fibre technology, and allow the fabrication of very compact and highly complex optical circuitry which can be produced on a single photonic chip. They also offer the potential to integrate photonic devices with semiconductor sources and detectors to realise a compact, hybrid photonic-optoelectronic chip, complete with fibre pig-tailing. Because of their compactness and potential low cost, these types of photonic chips are attractive components for future high-capacity optical telecommunications and other networks now being planned as part of the information super highway. The paper presents the physical constraints and design rules for the fabrication of the devices, and the research carried out using a helicon plasma reactor to grow the thick films of silica necessary for the waveguides. From the start, the reactor was designed to process substrates at low temperatures to allow the integration with other optical and electronic components on the same wafer. Hence a considerable amount of research was carried out on the relation between the plasma parameters and the physical properties of the films deposited. The last section of the paper describes the fabrication of an actual device; a 1:8 splitter, and its characteristics.

Simulation and experimental study of gray-tone lithography for the fabrication of arbitrarily shaped surfaces

Abstract: This paper reports on a study of a methodology for fabrication of arbitrarily shaped silicon structures using technologies common to standard IC manufacturing processes. Particular emphasis is put on the design and use of halftone transmission masks for the lithography step required in the fabrication process of mechanical, optical or electronics components. The experimental investigation and the design of gray-tone masks was supported by lithography simulation. Results are presented for both, simulated gray-tone patterns as well as experimental trials.

Fine fibres by melt extraction

Abstract: Methods for manufacturing fine fibres of metals and ceramics below 20 μm diameter are described. Some analysis of the fabrication process is given as well as a description of properties of the fibres. A brief account is also given of selected applications of the materials.

Lateral field emission devices and methods of fabrication

Abstract: Lateral cathode field emission devices and methods of fabrication are set forth. Conventional integrated circuit fabrication techniques are advantageously used to produce the lateral FEDs. Cathode tips on the order of several hundred angstroms are consistently obtained as well as exact spacing of the cathode to gate and cathode to anode. Various cathode and device configurations are described, including a circular field emission device. A single integrated structure having multiple cathodes and multiple gates is possible to perform various logic operations and/or enhance current output from the device. Multiple field effect devices, with cathodes disposed parallel or perpendicular to the substrate, are integrally coupled through a sharing of one or more metallization layers definitive of the elements of the devices. Significant advantages in current density and circuit layout can be obtained. Methods for fabricating the various devices are also explained.

Axially distorted 3–3 piezoelectric composites for hydrophone applications

Abstract: Application of reticulated ceramic technology to the fabrication of 3–3 lead zirconate-titanate (PZT)/Spurr epoxy composites has been investigated. Use of this technology provides a substantial improvement in manufacturability over other methods. Directional distortion of the ceramic structure to enhance the composite's hydrostatic response is also possible. Composite fabrication is described and the effects of distortion on the piezoelectric properties are presented. The results for K33 and g33 are found to be comparable to other 3–3 PZT/epoxy composites while d33 and hydrostatic gh are reduced with density.

Grating couplers in tapered waveguides for integrated optical sensing

Abstract: Design considerations and experimental results are presented for the fabrication and characterization of grating couplers in gradient effective index waveguides used for realizing miniature integrated optical sensor modules. Hard dielectric substrates such as glass and fused silica have been structured by photolithographic techniques, while hot embossing has been used for the grating fabrication in plastic substrates. The gradient effective index waveguides were produced by shadow mask evaporation techniques in one single deposition step in a rotating substrate holder arrangement. Optical diffraction measurements, atomic force microscopy, and a newly developed method based on performing spatially resolved grating coupler resonance angle measurements are shown to be valuable tools for the characterization of the waveguides and the grating couplers. The experimental results indicate that the deposition of high-index waveguiding films such as Ta2O5 and TiO2 on previously structured substrates is a viable technique for the cost-effective fabrication of integrated optical sensor chips.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Pyrodetector element having a pyroelectric layer produced by oriented growth, and method for the fabrication of the element

Abstract: A novel pyrodetector element is produced by oriented growth, with the aid of buffer layers, above a monocrystalline silicon substrate and thus enables the fabrication of an array of pyrodetectors having read-out and amplifier circuitry integrated on the common substrate. Proposed as the buffer layers are yttrium-stabilized zirconium oxide YSZ or magnesium oxide above an interlayer made of spinel.

Copper - Al2O3 composites prepared by reactive spray deposition

Abstract: There is considerable interest in the development of copper based alloys with high strength and high conductivity for applications in electronics and precision engineering. One of the families of such alloys is represented by the internally-oxidized copper alloys containing small amounts of fine Al[sub 2]O[sub 3] particles. While such materials are remarkable for their good strength combined with excellent thermal and electrical conductivity, their fabrication is extremely difficult and costly, requiring many processing stages such as metallic alloy powder preparation, heating with an oxygen source for internal oxidation, reduction of excess oxygen, consolidation, etc. Such difficulties have severely limited the applications of these materials. An alternative process under development for the fabrication of composites with a fine and uniform distribution of second phase is the spray forming method, and in particular this method combined with the injection of the second phase component or with the reaction of an active component with the atomizing gas. The present report describes some experiments aimed at preparing Cu-Al[sub 2]O[sub 3] composites with fine Al[sub 2]O[sub 3] particles by spraying a dilute Cu-Al alloy with an atomizing gas (nitrogen) containing deliberate additions of oxygen.

Fabrication of Silicon Quantum Wires Using Separation by Implanted Oxygen Wafer

Abstract: A new fabrication method of silicon quantum wires using separation by implanted oxygen (SIMOX) wafer has been proposed, which combines Si KOH anisotropic etching and local oxidation of silicon (LOCOS) techniques. In the fabrication, the cross-sectional dimensions of Si wires are determined solely by the thickness of the SOI layer. Using this novel method, we have fabricated a Si quantum wire with dimensions less than 100 nm and confirmed its great potential for making ultrafine structures without the need for high-resolution lithography or etching.

Semiconductor integrated circuit device fabrication method and its fabrication apparatus

Abstract: A semiconductor integrated circuit device fabrication technique improves the accuracy of element qualities by considering the influence of interaction of element quality parameters in the quality control of semiconductor fabrication processes and also by improving the product yield estimation accuracy so that the production efficiency can be improved. An initial value of a membership function is first set and then a plurality of element quality parameters and a combined quality parameter are expressed by membership functions in fuzzy control in a semiconductor fabrication apparatus for automating a fabrication method by connecting a computer with various measuring instruments and various processors by communication devices. Moreover, the combined quality parameters are fuzzy-inferred from the element quality parameters using these membership functions, inference rules are adjusted by data of the actual processes, the membership functions of the obtained element quality parameters are converted into an element quality control standard, and the semiconductor integrated circuit device fabrication processes are controlled in accordance with the standard.

Fabrication of high-energy x-ray transmission gratings for the Advanced X-ray Astrophysics Facility (AXAF)

Abstract: The High Energy Transmission Grating spectrometer (HETG) on the Advanced X-ray Astrophysics Facility (AXAF) requires the fabrication and assembly of hundreds of large area (approximately equals 6 cm2), low-distortion, ultra-fine-period transmission gratings efficient in the 0.4-10 keV band ((lambda) equals 1.2-30 angstroms). The spectrometer requires two types of gratings: Medium Energy Gratings (MEG), which have a period of 0.4 micrometers and consist of gold bars 0.4 micrometers thick, and High Energy Gratings (HEG), which have a period of 0.2 micrometers and consist of gold bars 0.7 micrometers thick. Both types are supported by 0.5-1.0 micrometers -thick polyimide membranes. The gratings are fabricated using a variety of techniques including interference lithography, tri-level resist processing, reactive-ion etching, and gold microplating. An earlier approach which utilized x-ray lithography has been abandoned. Recent efforts have focussed on improving the yield and robustness of the many complicated fabrication steps, and improving the profile of the grating bars. We present details of the fabrication procedure and discuss the issues associated with developing an optimal fabrication process.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Design and fabrication of thin film monolithic uncooled infrared detector arrays

Abstract: This paper discusses the design of monolithic thin film thermal detectors, with particular reference to the parameters which influence performance such as thermal conductance. Methods for implementing thermal isolation are described, and critical fabrication technology is outlined. Optional materials technology for thin film resistance bolometers is reviewed, and consideration is given to bias and signal conditioning techniques.

Reflection Mode Polymer-Dispersed Liquid Crystal Light Valve

Abstract: This paper describes the procedure for fabrication of a reflection-mode polymer-dispersed liquid crystal light valve (PDLCLV) consisting of a polymer-dispersed liquid crystal film, a diamondlike carbon film, a dielectric mirror, a Bi12SiO20 photoconductive crystal plate, and transparent electrode films. The many advantages of the PDLCLV include the lack of need for polarizers, high optical transmittance, high-speed response and ease of fabrication. The performance of the device as evaluated experimentally is as follows: optical transmittance 72%; extinction ratio 178/1; limiting resolution 34 lp/mm; and rise/decay times 14/15 ms. These values are suitable for the image converter of an optically addressed projection display. It has also been found that the resolution increases as the frequency of the AC voltage driving the PDLCLV decreases.

Replicated microstructures for integrated optics

Abstract: Fabrication technology and device structures suitable for low- cost production of replicated integrated optical devices are presented and discussed. Shim fabrication and replication techniques such as hot embossing and injection moulding are capable of achieving the submicron resolution, high fidelity requirements of integrated optical structures. Polymeric materials have been shown to be suitable both as replicated substrates and as waveguiding films with losses under 1 dB/cm. High index dielectric waveguiding films are highly suited to sensor applications and have been fabricated with losses under 5 dB/cm. New types of vertically structured integrated optical devices which can be fabricated by replicating a microstructure followed by dielectric coating are presented.