Showing papers on "Layer by layer published in 1993"

Internal structure of layer-by-layer adsorbed polyelectrolyte films : a neutron and X-ray reflectivity study

Abstract: Ultrathin polymer films were physisorbed to surface-modified Si wafers by electrostatic deposition of polyelectrolytes from aqueous solutions. For the first it has been demonstrated that the preparation procedure, which involves repeated dipping of the substrate into solutions of polycations and polyanions in an alternating sequence, leads to the deposition of continuous molecular layers that form a polymer film with a well-defined supramolecular structure

Layer-by-layer adsorbed films of polyelectrolytes, proteins or DNA

Abstract: During the last three years the authors have developed a new technique which allows to construct ultrathin multilayer assemblies by consecutive adsorption of anionic and cationic polyelectrolytes out of aqueous solution. The technique allows the easy construction of functional multicomponent films that can be deposited on surfaces with any given topology. They show excellent thermal stability and the total film thickness can be adjusted within a few {angstrom}s. Physisorbed films can be assembled with a linearly increasing thickness up to at least 100 layers. The films are transparent and exhibit a homogenous interference color in white light. The average thickness of individual layers can be adjusted with a precision of 0.5 {angstrom}. Film deposition can also be carried out using natural polyelectrolytes such as DNA or by biospecific binding to proteins such as strepavidin.

Layer-by-layer deposited multilayer assemblies of polyelectrolytes and proteins: from ultrathin films to protein arrays

Abstract: We have recently introduced a new method of creating ultrathin films of polyelectrolytes based on the electrostatic attraction between opposite charges. Multilayer assemblies are adsorbed in a layer-by-layer fashion from aqueous solutions of the polymers. The total film thickness can easily be adjusted by varying the ionic strength of the solution. Here, we report on the temperature stability and the water content of the multilayer assemblies. Furthermore, we have extended our concept to the incorporation of protein layers into films of synthetic polyelectrolytes. The well established system biotin/streptavidin was used to construct such multilayers, also by biospecific recognition. Adsorption of streptavidin onto previously photostructured precursor films leads to the deposition of the protein on selected areas on the substrate. The films were investigated by small-angle x-ray scattering (SAXS), Fourier Transform Infrared Spectroscopy (FTIR), and by fluorescence microscopy.

Electrophoretic deposition and its use to synthesize ZrO2/Al2O3 micro-laminate ceramic/ceramic composites

Abstract: Electrophoretic deposition has been employed to synthesize yttria-stabilized zirconia (YSZ)/alumina, laminar microcomposites with a total of 80 layers, >2mm. 10 wt% solids, ethanol suspensions of YSZ or Al2O3 powders were deposited layer by layer. The deposited samples had a green density, ~60% theoretical. The deposition process was characterized by the rate-of-deposition as a function of voltage and the microstructure of the sintered, theoretically dense samples was characterized by optical and electron microscopy. Microindentation was used to explore the mechanical properties of the laminates.

Preparation of High-Quality Microcrystalline Silicon from Fluorinated Precursors by a Layer-by-Layer Technique

Abstract: Microcrystalline silicon thin films exhibiting high crystallinity and high quality were successfully fabricated from the fluorinated precursors SiHnFm (n+m≤3) by repeating the deposition of very thin layers, 10 nm thick, and by treatment with atomic hydrogen. Hydrogen concomitant with dangling bonds is efficiently removed from the Si network at the levels of 0.45 at.% and 3.7×1016 spins/cm3, respectively. A specific texture showing a strong orientation toward (220) is observed in the X-ray diffraction (XRD) spectra. High photoconductivity and a considerable diffusion length of 400 nm for holes under the ambipolar condition verify the films' high quality and high crystallinity.

Layered electrodes with inorganic thin films and method for producing the same

Abstract: A method for the preparation of layered electrodes, including ultramicroelectrodes, through application of a thin film coating of an inorganic material to a conductor by use of chemical vapor deposition. The chemical vapor deposition techniques of the present invention provide a layered electrode that is efficiently and effectively manufactured in a standard reaction chamber at atmospheric pressure. The preferred conductors are carbon fibers and foams, and metal (platinum or gold) wires, meshes and foams. The precursors for the thin film deposition include those that yield thin-films of insulators, semiconductors, metals, and superconductors. During the chemical vapor deposition process, a thin film coating is formed on the conductor by the pyrolytic decomposition of the precursor vapor at the surface of the heated conductor. The hardness and rigidity of the thin film layer imparts durability and structure to the fragile and flexible conductors without significantly increasing the size of the device. The variable parameters in the deposition process are monitored and controlled so that the desired thickness of thin film coating will be obtained.

Fabrication of a thin film transistor and production of a liquid crystal display apparatus.

Abstract: A thin film transistor includes: an insulating film having a surface; a semiconductor film formed on the surface of the insulating film; a source electrode and a drain electrode which are in contact with the semiconductor film; and a gate electrode which is electrically insulated from the semiconductor film. In the thin film transistor, a portion of the semiconductor film at distances of less than 500 angstroms from the surface of the insulating film contains at least silicon including a microcrystalline structure having a conductivity of 5 x 10⁻⁹ S/cm or more. Also, a method for fabricating such a thin film transistor is disclosed. The method includes a step of forming a semiconductor film including a silicon layer having a microcrystalline structure by repeatedly performing the following steps (1) and (2): (1) forming a silicon layer on an insulating film by decomposing a material gas including Si which is introduced into a reaction chamber of a plasma chemical vapor deposition apparatus; and (2) microcrystallizing the silicon layer by introducing the hydrogen gas into the chamber to perform a hydrogen plasma treatment for the silicon layer.

Organic thin film type light emitting element

Abstract: PURPOSE: To prevent an organic thin film layer from being turned into a bound object and stabilize the light emitting performance when a light emitting element of EL type is formed from an organic thin film, by forming an organic thin film layer from a light emission layer and electric charge implanting layer, and absorbing dispersively in a metal thin film layer a high energy which is to be impressed when a transparent positive electrode film formation is conducted. CONSTITUTION: Through a thin metal film layer 6, a transparent positive electrode 7 is laminated on a light emission layer 4 cosisting of an organic thin film so that a light emitting element is accomplished. A high energy at this time of film formation for a positive electrode 7 according to the described construction, is absorbed dispersively in the metal thin film layer 6 so that the light emission layer 4 is prevented from being turned into a bound object, and thereby drop of film quality of the layer 4 is avoided. Concretely described, the light emitting element is composed of insulative base board 1 of glass, etc., metal negative electrode 2, electron implantation layer 3, light emission layer 4, positive electrode implantation layer 5, thin metal film layer 6, transparent positive electrode 7, and power supply 8. The thin metal film layer 6 is made of platinum, gold, silver, etc., for enhancing the tight attachment with the implantation layer 5 which serves as an underlay, while the positive electrode 7 is formed from a transparent conductive film such as indium tin oxide. COPYRIGHT: (C)1994,JPO

Method of forming thin film for semiconductor device

Abstract: A method of forming a thin film for a semiconductor device, for forming a metal thin film by chemical vapor deposition on an intermediate layer which is provided on a substrate, comprises the steps of activating the surface of the intermediate layer by introducing a halide gas of a metal for forming the thin film onto the surface of the intermediate layer, forming nuclei on the surface of the intermediate layer by introducing a silane-system gas onto the activated surface of the intermediate layer, and introducing the halide gas and a reducing gas onto the surface of the intermediate layer formed with the nuclei, thereby depositing the metal thin film on the surface of the intermediate layer.

Process for producing multilayered film materials

Abstract: A multi-layered film material having a structure wherein a protective layer, a composite film comprising a polyvinyl alcohol film or a film of an ethylene/vinyl acetate copolymer saponificate and a silicon oxide deposition layer formed on the former, and a heat-sealable polyolefin layer are laminated In this case, each of the layers is transparent and the silicon oxide layer is disposed on the side of the protective layer The protective layer and the composite film, and the composite film and the heat-sealable polyolefin layer are laminated by an adhesive layer, respectively

Method of making thin film transistors

Abstract: When a thin film transistor is formed by forming a polycrystalline silicon thin film of a large grain size, the uniformity of film quality within an active region can be improved more reliably, whereby a carrier mobility of a transistor can be suppressed from being fluctuated. Therefore, the thin film transistor can be enhanced in efficiency. There is provided a method of making a thin film transistor in which a dot-shaped core from which crystal is to be grown is produced on an amorphous silicon thin film at its predetermined location and solid phase growth is performed to grow crystal to thereby form a silicon thin film. The core from which crystal is to be grown is produced on the thin film transistor at its portion near the outside of a region in which an active region is formed.

Extension of the layer-by-layer growth regime of InxGa1-xAs on GaAs (001)

Abstract: In order to delay the occurrence of the 2D-3D growth mode transition in highly strained InxGa1-xAs epitaxial layers grown on GaAs (001) by molecular beam epitaxy, the mass transport at the surface should be reduced. This can be achieved by increasing the growth rate. It is demonstrated in this letter that this is an efficient way to increase the critical thickness for which the 3D growth appears.

Method for forming a titanate thin film on silicon, and device formed thereby

Abstract: A method for forming a dielectric layer onto a substrate having a silicon surface includes initially depositing an oxidizable metal thin film onto the surface and thereafter depositing a thin film of a metal titanate compound, such as the zirconium titanate. The metal thin film is preferably formed of tantalum, titanium or zirconium. Following deposition of the metal titanate thin film, the metal titanate is annealed by heating in an oxidizing atmosphere at a temperature effective to recrystalize the titanate to increase the dielectric properties. During annealing, the metal film reacts with oxygen to form a metal oxide thin film intermediate the metal titanate thin film and the silicon surface. The oxidation of the metal thin film inhibits oxidation of the underlying silicon that would otherwise reduce the effective capacitance of the dielectric layer. The resulting coated substrate thus includes a dielectric layer that includes a thin film of the oxidized metal and an oxygen-annealed metal titanate thin film and exhibits an increased effective capacitance and improved dielectric properties, particularly in comparison to a comparable oxygen-annealed titanate films formed directly onto silicon surfaces.

Thin Film Analysis

Abstract: Grimm (1968) was the first to demonstrate the principle of using a glow discharge lamp for the analysis of flat samples.(1) Since the Grimm lamp appeared, low-pressure gas discharges have found many applications. Several authors have investigated the potentialities of such a discharge.(2–9) Principal applications are in the bulk analysis of metals or of nonconducting materials pressed into pellets with a conducting binder. Several other configurations have been described for bulk analysis, mostly to improve the sensitivity, e.g., hollow cathodes,(10,11) boosted lamps,(12,13) and magnetic field-enhanced glow discharges.(14)

Manufacture of multilayered board

Abstract: PURPOSE:To improve the form and the adhesion of a conductor pattern, and simply effectively enable inspection before pattern plating CONSTITUTION:An interlayer insulating layer I1 is formed on a board 1 by performing exposure development and curing treatment after the coating of photosensitive resin By sputtering metal capable of improving the adhesion of a conductor pattern C2, a Cr thin layer L1 as a first layer metal thin layer is formed on the interlayer insulating film I1 A Cu thin film L2 as a second layer metal thin layer is formed on the Cr thin layer L1 by sputtering A Cr thin layer L3 as a third layer metal thin layer is formed on the Cu thin layer L2 by sputtering On the Cu thin layer L3, plating resist 3 is formed, the Cr thin layer L3 is eliminated, and the Cu thin layer L2 is partially exposed A copper-plated layer L4 is formed on the exposed Cu thin layer L2 The plating resist 3 and the metal thin layers L1-L3 are eliminated The above process is repeated

Thin Film Structures

Abstract: We review the current methods of fabricating HTS thin film device structures. The use of these methods is illustrated by an overview of approaches to the fabrication of Josephson junctions.

Semiconductor substrate having a thin film semiconductor layer bonded on a support substrate through an adhesive layer

Abstract: A thin film semiconductor substrate for a display device includes a thin film semiconductor circuit layer formed on a single crystal semiconductor substrate and a support substrate formed over the thin film semiconductor circuit layer An adhesive layer made of a fluorine-containing epoxy family adhesive is provided between the insulating layer and the support substrate When the single crystal semiconductor substrate is removed, the yield rate in production of the thin film semiconductor substrate is greatly improved

Method of making staggered gate MOSTFT

Abstract: On an insulating film (12) covering the surface of a semiconductor substrate (10), a gate electrode layer (14), a gate insulating film (16), and a semiconductor layer (18) such as silicon are sequentially deposited to form an under-gated MOS transistor. A flat coating film such as resist is formed covering the semiconductor layer (18). The coating film is then etched back to expose the surface of the semiconductor layer (18) at the area above the gate electrode layer (14). The left coating film is used as the mask for the selective growth of a mask material layer (24) such as tungsten on the exposed surface of the semiconductor layer (18) with a side-projection. After removing the left coating film, impurity ions such as BF2 are selectively injected in the semiconductor layer (18) using the mask material layer (24) as the mask to form a source region (18S) and a drain region (18D).