Showing papers on "Fabrication published in 1990"
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TL;DR: In this paper, ammonium hydroxide-water (AHW) solutions for micromachining monocrystalline silicon are described, which can be applied under clean-room conditions within standard IC fabrication lines.
Abstract: Wet chemical etchants based on ammonium hydroxide-water (AHW) solutions for micromachining monocrystalline silicon are described. The etchants can be applied under clean-room conditions within standard IC fabrication lines. The nature of AHW solutions is discussed with respect to anisotropy and selectivity. At 75 °C and 9 wt.% AHW, a maximum etch rate for (100) silicon of approximately 30μm/h has been determined. (111):(100) etch rate ratios show values around 4%. AHW etchants exhibit an excellent selectivity to SiO 2 , Si 3 N 4 and highly boron-doped silicon. Aluminium will not be attacked by silicon-doped AHW etchants. Therefore, standard IC metallization techniques can be used for device fabrication. The application of AHW solutions to the fabrication of basic micromechanical structures is demonstrated.
103 citations
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TL;DR: In this paper, different thin film fabrication techniques of ferro-and piezoelectric materials are described with special emphasis on rf sputtering, the relative advantages and disadvantages of oxide and metallic targets, and the control of stoichiometry by adjusting the target substrate distance and composition of target.
Abstract: Different thin film fabrication techniques of ferro- and piezoelectric materials is described with special emphasis on rf sputtering. The relative advantages and disadvantages of oxide and metallic targets, and the control of stoichiometry by adjusting the target substrate distance and composition of target is described. The possible applications of ferroelectric films in non-volative memories, pyroelectric detectors, electro- and acousto-optic devices is briefly presented. The applications of these films in the fabrication of integrated Surface Acoustic Wave (SAW) devices on Silicon is discussed in some detail. Theoretical calculations of SAW transduction in layered media is used to compare selected ferroelectric (PZT, PbTiO3. LiNbO3 and BaTiO3) and piezoelectric (ZnO, AIN and CdS) films on silicon for their use in SAW devices.
83 citations
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TL;DR: In this article, an electrostatic bonding using sputtered low melting point glass as an intermediate layer has been performed for the fabrication of intelligent sensors and microelectromechanical systems, which can be used for the automatic identification of micro-structures.
Abstract: Room-temperature silicon-to-silicon bonding has been performed. It is an electrostatic bonding using sputtered low melting point glass as an intermediate layer. Wafers can be bonded at room temperature with an applied voltage of about 50 V. This technique is useful for the fabrication of intelligent sensors and microelectromechanical systems.
67 citations
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TL;DR: In this article, a focused ion beam has been used for the fabrication of transmission electron microscopy specimens in pre-selected regions, with no induced artefacts, and the lateral accuracy achievable in the selection of an area for cross-sectional analysis is better than one micrometer.
Abstract: A new technique using a focused ion beam has been developed for the fabrication of transmission electron microscopy specimens in pre-selected regions. The method has been proven in the fabrication of both cross-sectional and planar specimens, with no induced artefacts. The lateral accuracy achievable in the selection of an area for cross-sectional analysis is better than one micrometre. The technique has been applied to a number of silicon and III-V based integrated circuits, and is expected to be suitable for many other materials and structures.
60 citations
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59 citations
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TL;DR: In this article, a general theoretical approach to the modeling of several different process steps in fabrication of ion exchanged channel waveguides is presented, and several commonly used fabrication processes are included, and the nature of the ion source and the effect of external electric voltage are taken into account.
Abstract: A general theoretical approach to the modeling of several different process steps in fabrication of ion‐exchanged channel waveguides is presented. All of the commonly used fabrication processes are included, and the nature of the ion source and the effect of external electric voltage are taken into account. The model uses a numerical finite‐difference calculation of diffusion in the glass with boundary conditions and electrical current distribution chosen according to the process being modeled. A single computer program includes the model, and can be used for simulating a fabrication process with different successive process steps. Several calculated examples are given, all with experimentally obtained parameters for Ag+ ‐Na+ exchange in Corning 0211 glass.
57 citations
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TL;DR: In this article, the authors reported the calculation and fabrication of periodic phase structures for fan-out elements with a theoretical conversion efficiency close to 100% and perfect uniformity, and measured an efficiency of 92% for a smooth kinoform structure fabricated in photoresist by laser beam writing lithography.
Abstract: This paper reports the calculation and fabrication of periodic phase structures for fan-out elements with a theoretical conversion efficiency close to 100% and perfect uniformity. We have measured an efficiency of 92% for a smooth kinoform structure fabricated in photoresist by laser beam writing lithography.
57 citations
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53 citations
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TL;DR: In this article, the transformation of precursors to sol, sol to gel, and gel to crystalline phase were characterized using spectroscopy and x-ray diffraction.
Abstract: Integration of ferroelectrics in the current generation of electronic/photonic devices not only enhances the functional capabilities of these devices but also has potential for a variety of new applications. The fabrication of ceramic thin films and fibers is enabled by sol-gel process. This fabrication process is well-controlled, low-cost and compatible with existing fabrication technologies. This study focussed on the fabrication of PLZT 7/65/35 ceramic thin films and fibers from lead acetate hydrate, lanthanum acetate hydrate, zirconium n-propoxide and titanium n-propoxide utilizing acid catalysis. The transformations of the precursors to sol, sol to gel and gel to crystalline phase were characterized using spectroscopy and x-ray diffraction. The films were formed by spin-coating the hydrolyzed precursor sol on various substrates: conductors (Au, Al, Pt), semiconductors (Si [100], Si [111]) and insulators (fused SiO2, Al2O3, MgO). The fibers were drawn from the similar sols. These films and fibers were...
45 citations
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TL;DR: In this paper, a quasi-steady state approach is applied to model the pressure-driven, temperature-gradient chemical vapor infiltration (improved CVI process) for ceramic matrix composites fabrication.
Abstract: A quasi-steady-state approach is applied to model the pressure-driven, temperature-gradient chemical vapor infiltration (improved CVI process) for ceramic matrix composites fabrication. The deposited matrix in this study is SiC which is converted from the thermal decomposition of methyltrichlorosilane gas under excess hydrogen. A three-dimensional unit cell is adopted to simulate the spatial arrangements of reinforcements in discontinuous fiber mats and three-dimensionally woven fabrics. The objectives of this paper are to predict (1) the temperature and density distributions in a fibrous preform during processing, (2) the advancement of the solidified front, (3) the total fabrication period, and (4) the vapor inlet pressure variation for maintaining a constant flow rate. Furthermore, the effect of boundary temperature and inlet pressure variations on the total proassing period is also studied. The fabrication temperature examined in this paper is in the range between 873 and 1473 K, and the pressure is from 1.0001 to 2.0000 atm (1.0134 × 105 to 2.0265 × 105 Pa). Based upon this analysis, the influence of the reactor condition on the density of the final product in a CVI process can be quantified.
43 citations
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TL;DR: The theory, fabrication, and performance of monolithic 4 x 4 single-mode fused couplers is reported, and measurements show that the device exhibits excellent coupling uniformity and low excess loss.
Abstract: The theory, fabrication, and performance of monolithic 4 × 4 single-mode fused couplers is reported The field coupling matrix is derived and used to show that a device having equal coupling between the four fibers may be obtained The fabrication of such a device is described, and measurements show that the device exhibits excellent coupling uniformity and low excess loss The wavelength response of a device designed for equal coupling at 153 μm is shown between 12 and 16 μm
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23 Jul 1990TL;DR: A metallization system for contacting semiconductor materials employed in high temperature applications that is thermally stable is described in this paper, where the system can be utilized in the fabrication of electronic devices such as diodes, lasers, transistors, solar cells, and integrated circuits comprised of such devices.
Abstract: A metallization system for contacting semiconductor materials employed in high temperature applications that is thermally stable. The system can be utilized in the fabrication of electronic devices such as diodes, lasers, transistors, solar cells, and integrated circuits comprised of such devices.
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TL;DR: In this article, a magnetically actuated valve, manufactured by silicon and thin-film micromachining, is considered, and an analysis of the magnetic circuit is made to determine the critical design parameters, and a fabrication sequence is described.
Abstract: In this paper, a magnetically actuated valve, manufactured by silicon and thin-film micromachining, is considered. An analysis of the magnetic circuit is made to determine the critical design parameters, and a fabrication sequence is described. An integrated array of these microvalves, when combined with chemical microsensors, is intended to form the basis of an automated flow distribution and chemical analysis system. The feasibility of magnetic actuation, an addressing scheme, and the fabrication process are discussed.
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TL;DR: In this article, a nanometer-scale gratings have been fabricated in InP and InGaAs/InP heterostructures using electron-beam lithography and reactive ion etching in methane-hydrogen plasmas.
Abstract: Nanometer‐scale gratings have been fabricated in InP and InGaAs/InP heterostructures using electron‐beam lithography and reactive‐ion etching in methane‐hydrogen plasmas. It is shown that the slight overcut obtained in the etch profiles during a single‐step etch in CH4/H2 is due to polymer formation on inert mask surfaces and edges. Intermittent removal of the deposited polymer film is shown to be effective in obtaining anisotropic profiles. Highly anisotropic 35‐nm‐wide InP lines at 70‐nm pitch demonstrate the potential of this fabrication process. The formation of 100‐nm‐wide free‐standing InP wires is also presented.
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TL;DR: In this article, a new approach is presented for the development of a metal-insulator-semiconductor field effect transistor technology, which is applied to the optimization of Al 2O3/InP structures prepared by the deposition of evaporated Al2O3 on arsenic stabilized InP surfaces.
Abstract: A new approach is presented for the development of a metal‐insulator–semiconductor field‐effect transistor technology. It is applied to the optimization of Al2O3/InP structures prepared by the deposition of evaporated Al2O3 on arsenic‐stabilized InP surfaces. Molecular beam epitaxy and surface‐science techniques (reflected high‐energy electron diffraction and x‐ray photoelectron spectroscopy are used to control step by step the fabrication of the structures and to describe the microscopic properties of the interfaces. The optimization of the fabrication process is based on correlations between interfacial physicochemical properties and metal–insulator‐semiconductor capacitor electrical properties. It is shown that an interfacial oxide buffer layer can favor crystallochemical matching between Al2O3 and InP.
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TL;DR: In this article, the authors describe the fabrication of disk shaped functionally gradient material with an optimum distribution of composition for thermal stress reduction in a specific material combination of PSZ/Stainless Steel.
Abstract: The fabrication of disk shaped functionally gradient material with an optimum distribution of composition for thermal stress reduction in a specific material combination of PSZ/Stainless Steel is described. The thermal stress generated during cooling from sintering temperature was analized by finite element method as a function of conpositional distribution and sample size.According to the optimum compositional gradient, the sintered compact of the PSZ /SUS304 functionally gradient material was successfully fabricated.
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TL;DR: A new laser-based method was developed for fabrication of microlenses on flat quartz plates using a CO(2) laser to heat a quartz surface and induce thermal reactions for source gases of SiH(4) and NO.
Abstract: A new laser-based method was developed for fabrication of microlenses on flat quartz plates. In this method, a CO(2) laser is used to heat a quartz surface and induce thermal reactions for source gases of SiH(4) and NO. Even as-grown silicon oxide deposits have the spherical thickness distribution required for a lens at the center and this useful area can be further increased by wet etching. Microlenses were checked on a Fizeau interferometer for surface accuracy and aberrations. As a demonstration, a 14-microm thick microlens was used for collimating light from an optical fiber.
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TL;DR: In this article, the in situ fabrication of YBCO (YBa2Cu3Oy)/MgO/Au epitaxial planar tunnel junctions with a thin MgO barrier utilizing an electron-beam coevaporation technique is reported.
Abstract: The in situ fabrication of YBCO (YBa2Cu3Oy)/MgO/Au epitaxial planar tunnel junctions with a thin MgO barrier utilizing an electron-beam coevaporation technique is reported. The thickness of the MgO barrier is 3–12 nm and the tunnel resistance shows a strong dependence on barrier thickness. The fabricated tunnel junctions are highly reproducible and controllable. The observed tunnel characteristics contain the gap opening at about 20 mV and the anomaly around zero bias. The tunnel characteristics using the degraded films are also reported.
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01 Oct 1990-Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology
TL;DR: In this paper, micro-electro discharge machining (MEDM) using water as a working fluid, with its advantages of high removal rate and low electrode wear without formation of carbonaceous material, was applied to the fabrication of narrow slits used for ultra-violet spectrometers.
Abstract: Micro-electro discharge machining (MEDM) using water as a working fluid, with its advantages of high removal rate and low electrode wear without formation of carbonaceous material, for deep micro-hole drilling with large ratios of depth to diameter is applied to the fabrication of narrow slits used for ultra-violet spectrometers. The optimum condition for narrow slit fabrication is investigated concerning the electric discharge circuit and combinations of electrode, workpiece materials and electrode polarity. As a result, it is possible to fabricate fine slits as narrow as 20 μm wide and 3 mm long with fairly fine surface roughness of around 1 μm. Comparative estimation with an optical diffraction method shows that slits made by MEDM and commercially available ones made by photoetching are both of the same level in quality as determined from the higher order spots of the diffraction pattern. The MEDM method is superior to photoetching in fabricating finer and more accurate slits much faster.
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02 Jul 1990
TL;DR: In this paper, an electrochemical cell electrode such as the cathode element for a high energy density battery cell and its fabrication sequence are disclosed, where material such as finely-divided carbon particles are dispersed over the electrode surface during an ultrasonic energy assisted wet spraying process.
Abstract: An electrochemical cell electrode such as the cathode element for a high energy density battery cell and its fabrication sequence are disclosed. Material such as finely-divided carbon particles is dispersed over the electrode surface during an ultrasonic energy assisted wet spraying process which produces very thin electrodes that are also low in fabrication cost and increased in uniformity and energy density capability. Fine particle material deposition on both a metal foil electrode and on an insulating member that is later joined to a metal foil electrode are contemplated.
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15 Feb 1990
TL;DR: Germano-silicate optical fibres have been fabricated by MCVD with a refractive index difference between the core and the cladding glass of up to 0.05 as mentioned in this paper.
Abstract: Germano-silicate optical fibres have been fabricated by MCVD with a refractive index difference between the core and the cladding glass of up to 0.05. It is demonstrated that by depositing within Vycor tubes during preform fabrication, fibre may be subsequently drawn at lower temperatures than are possible with conventional silica preforms and this reduces the germania-induced excess loss. The performance of such fibres as Raman fibre amplifiers is discussed with particular reference to their bandwidth for applications in 1.5 - 1.6 AM telecommunications systems.
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15 Jan 1990TL;DR: In this paper, organic polymeric materials designed for electro-optic waveguide device fabrication and a fabrication method for low loss integrated optical devices are reported, which are methacrylic chain polymers with nonlinear optical moieties attached as side chains through variable length spacer groups.
Abstract: In this paper, we are reporting on organic polymeric materials designed for electro -optic waveguide device fabrication and a fabrication method for low lossintegrated optical devices. These polymers are methacrylic chain polymers with non -linear optical moieties attached as side chains through variable length spacer groups. Variation of the spacer length allows the tailoring of the phasestructure of the polymers as well as the glass transition temperature.' Forelectro -optic device use, the most important material parameter is r3 , thelargest tensor element of the electro -optic tensor. We have developed polymericmaterials with r33 values as high as 45 pm/V at 1.3 microns (98 pm/V at 632 nm)using an electrical poling process. Additionally, we have characterized opticaland electrical properties of the polymer films. Further, a fabrication processfor waveguide electro -optic devices from the polymers has been developed andintegrated modulators have been built. BACKGROUND
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TL;DR: Trenches in a layer of SiO2 on Si, with feature sizes down to 0.125 μm have been filled with tungsten (W) using selective chemical vapor deposition (CVD).
Abstract: Trenches in a layer of SiO2 on Si, with feature sizes down to 0.125 μm have been filled with tungsten (W) using selective chemical vapor deposition (CVD). The trenches were formed in a fashion similar to contact vias by reactive ion etching the SiO2 to the underlying silicon. The tungsten was then deposited in a cold wall CVD reactor, by silane reduction of WF6, to a thickness of 0.5 μm. The process results in good planarity and uniformity making it suitable for the fabrication of sub‐0.5 μm contacts and interconnects, and for the formation of high aspect ratio absorbers in x‐ray masks.
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24 Jul 1990TL;DR: An optical waveguide fabrication technique utilizing a self-aligned cladding has been proposed in this paper, in which an efficient and reliable optical waveguides can be fabricated with minimum proton exchange.
Abstract: An optical waveguide fabrication technique utilizing a self-aligned cladding, in which an efficient and reliable optical waveguide can be fabricated with minimum proton exchange; the guided mode property of the optical waveguide can be widely adjusted; and the optical waveguides can be fabricated in various types.
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TL;DR: The fabrication and properties of 0.28 NA, 100/140 μm, multimode alumino-silicate fiber doped with 7.5 wt% Nd3+ is reported in this article.
Abstract: The fabrication and properties of 0.28 NA, 100/140 μm, multimode alumino-silicate fibre doped with 7.5 wt% Nd3+ is reported. These fibres show excellent potential for use as the sensing element in intrinsic optical fibre temperature sensors.
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15 Feb 1990TL;DR: A number of fiber fabrication methods have evolved in response to the interest in active fiber devices based on rare earth doped core silicate fiber as mentioned in this paper, and a description of fabrication methods along with associated host composition and waveguide design issues are presented.
Abstract: A number of the fiber fabrication methods have evolved in response to the interest in active fiber devices based on rare earth doped core silicate fiber. Descriptions of fabrication methods along with associated host composition and waveguide design issues will be presented.
01 Jan 1990
TL;DR: In this article, a new class of organic dielectrics, benzocyclobutenes, are described and their application to the fabrication of thin-film multichip modules is detailed.
Abstract: A new class of organic dielectrics, benzocyclobutenes, 1, are described and their application to the fabrication of thin film multichip modules is detailed. Key properties for 3, a siloxy containing BCB derivative include low dielectric constant (2.7), low loss (0.008 at 1 MHz), low water absorption (0.25% after 24 h water boil) and high degree of planarization (>90% from one layer coverage). All other properties meet the requirements necessary for fabrication of thin film MCM structures.