Showing papers on "Indium tin oxide published in 1995"

Excimer laser processing of indium‐tin‐oxide films: An optical investigation

Abstract: dc sputtered indium‐tin‐oxide films have been excimer laser irradiated at subablation threshold fluences (<510 mJ/cm2). Optical characterization of irradiated products has been performed aiming at resolving the finer structure appearing in the IR–visible absorption spectra, as a function of laser fluence, and assigning such features to specific electronic defects which are produced upon irradiation. Four individual Gaussian‐like contributions to absorption spectra are identified at 0.7, 1.0, 1.6, and 2.6 eV, the intensity of which is observed to vary with fluence. Being absent in the original films and emerging in optical spectra at fluences exceeding 300 mJ/cm2, the 2.6 eV contribution is most characteristic to excimer laser processing and is responsible for the darkening of the film. Thermal model calculations reveal that such defects are produced only upon melting and fast resolidification of the film. The evolution of the chemistry actually taking place in the film upon irradiation is followed by x‐ra...

Electrochemical and thermal oxidation of TiN coatings studied by XPS

Abstract: X-ray pbotoelectron spectroscopy (XPS) has been used to investigate the electrochemical and thermal oxidation of titanium nitride (TiN) coatings prepared by physical vapour deposition (PVD) at 200°C. Electrochemical oxidation of TiN was carried out at various potentials in phthalate buffer solution (pH 5.0). Evaluation of the XPS Ti 2p and N 1s spectra showed the presence of nitride, oxynitride and oxide species in the layer formed by anodic oxidation. The electrochemical oxidation of TiN to TiO 2 proceeds through the formation of a mixed oxynitride/oxide layer, which transforms into oxide (TiO 2 ) at sufficiently positive potentials (E > 1.1 V vs. SHE). The oxidation of TiN to TiO 2 is accompanied by the formation of molecular nitrogen (N 2 ). The thickness of the oxide layer reaches ∼ 7 nm after oxidation at the highest potential (1.9 V). A complete coverage of the TiN surface by TiO 2 leads to an anodic peak in the polarization curve. On the basis of angle-resolved XPS measurements, two types of oxynitride species are identified, which are distributed differently throughout the oxidized layer. X-ray photoelectron spectroscopy depth profiles of TiN oxidized at 450°C and 600°C in an oxygen flow reveal that at the lower temperature an oxynitride layer is formed, whereas a thick TiO 2 layer appears on top of TiN at the higher temperature. The interface between the nitride and oxide phases is relatively sharp. It is suggested that the mechanism of TiN oxidation proceeds by a progressive replacement of nitrogen by oxygen. The TiN coatings can be used up to 600°C as a protective coating in an oxygen atmosphere. Valance band spectra of TiN, as well as of electrochemically and thermally oxidized TiN, are presented and discussed.

Patterned self-assembled monolayers formed by microcontact printing direct selective metalization by chemical vapor deposition on planar and nonplanar substrates

Abstract: Self-assembled monolayers (SAMs) of alkylsiloxanes were patterned by microcontact printing (μCP) on a number of substrates : N/Al 2 O 2 , Si/SiO 2 , TiN/TiO 2 , glasses, indium tin oxide (ITO), and plasma-modified polyimide. The patterned SAMs on these surfaces define and direct the selective chemical vapor deposition (CVD) of copper using (hexafluoroacetylacetonato)(vinyltrimethylsilane)copper(I) (Cu I (hfac)(vtms)) as the source gas. This paper presents several examples of microstructures of copper fabricated by selective, SAM-directed CVD, including fabrication of thin-film interconnects (with feature sizes of 0.5-100 μm), and selective filling of trenches and vias (models of microstructures having high aspect ratios) with feature sizes below 1 μm.

Patterning of dielectric oxide thin layers by microcontact printing of self-assembled monolayers

Abstract: This communication describes a technique used to pattern oxide thin layers using microcontact printing ({mu}CP) and sol-gel deposition. The technique involves {mu}CP of self-assembled monolayers (SAM`s) of alkylsiloxane on various substrates (SiO{sub 2}/Si, sapphire, ITO, and glass), followed by deposition of oxide thin layers from sol-gel precursors. Delamination of oxide layers from SAM-derivatized regions allows selective deposition of crystalline dielectric oxide layers on underivatized regions. To demonstrate the viability of this technique for integrated microelectronics and optics applications, patterned (Pb,La)TiO{sub 3} (PLT) and LiNbO{sub 3} layers were deposited on sapphire, silicon, and indium tin oxide (ITO) substrates. Use of lattice-matched substrates allows lithography-free deposition of patterned heteroepitaxial oxide layers. Strip waveguides of heteroepitaxial LiNbO{sub 3} with 4 {mu}m lateral dimensions were fabricated on sapphire. Dielectric measurements for patterned PLT thin layers on ITO are also reported. {copyright} {ital 1995} {ital Materials} {ital Research} {ital Society}.

Organic thin film luminescent element

Abstract: PROBLEM TO BE SOLVED: To provide an organic thin film luminescent element, which can reduce the energy barrier between a positive hole transporting layer and a light emitting layer and which can emit the light at a low voltage and which has a high light emitting efficiency, by using a metal oxide thin film having a work function larger than that of the indium tin oxide(ITO) for positive electrode. SOLUTION: This luminescent element is formed by forming a positive electrode 12 on a substrate 10, and forming an organic compound layers such as a positive hole transporting layer 18 and a light emitting layer thereon, and forming a negative electrode 14 thereon. In this case, the positive electrode 12 is made of the metal oxide thin film having a work function larger than that of ITO or the two-layer structure thin film forming the two-layer structure with ITO.

Process for fabricating ferroelectric integrated circuit

Abstract: An oversize ferroelectric capacitor is located against the contact hole to the MOSFET source/drain in a DRAM. A barrier layer made of titanium nitride, titanium tungsten, tantalum, titanium, tungsten, molybdenum, chromium, indium tin oxide, tin dioxide, ruthenium oxide, silicon, silicide, or polycide lies between the ferroelectric layer and the source drain. The barrier layer may act as the bottom electrode of the ferroelectric capacitor, or a separate bottom electrode made of platinum may be used. In another embodiment in which the barrier layer forms the bottom electrode, an oxide layer less than 5 nm thick is located between the barrier layer and the ferroelectric layer and the barrier layer is made of silicon, silicide, or polycide. A thin silicide layer forms and ohmic contact between the barrier layer and the source/drain. The capacitor and the barrier layer are patterned in a single mask step. The ends of the capacitor are stepped or tapered. In another embodiment both the bottom and top electrode may be made of silicon, silicide, polycide or a conductive oxide, such as indium tin oxide, tin dioxide, or ruthenium oxide.

Calculation of the figure of merit for indium tin oxide films based on basic theory

Abstract: Indium tin oxide (ITO) exhibits some of the most impressive properties such as high electrical conductivity and high optical transparency. These qualities have competing mechanisms which give rise to the need for a compromise between the transmission and conductivity. In order to optimize the conductivity and the transmission as a function of doping, it is necessary to determine the figure of merit as a function of the carrier concentration. We have compared different figures of merit as a function of carrier concentration on the basis of basic theoretical concepts instead of experimental values of conductivity and transmission. Estimates of the refractive index (n) and the extinction coefficient (k) are made and used to predict the optical transmission as a function of the carrier concentration in the films. It appears there is an optimum value of doping in ITO thin films.

Optical recording medium

Abstract: PURPOSE:To effectively prevent the sticking of dust by forming a recording layer on an optically transparent substrate and incorporating an electric conductive material into the substrate so that the surface electric resistivity of one side of the substrate opposite to the recording layer side is specified CONSTITUTION:A recording layer 6 consisting of an inorg dielectric film 2, an amorphous recording film 3 and an inorg dielectric film 4 is formed on a transparent polycarbonate substrate 1 and an electric conductive material is incorporated into the substrate 1 so that the surface electric resistivity of one side of the substrate 1 not confronting the recording layer 6 is regulated to OMEGA/sq Electric conductive transparent particles of tin antimony oxide, indium tin oxide, etc, not hindering the transmission of laser beams in the substrate are used as the electric conductive material It is made unnecessary to form an electric conductive film on the surface of the substrate in a new process and the objective optical recording medium to which dust sticks hardly is obtd at a low cost

Integrated liquid crystal display and backlight system for an electronic apparatus

Abstract: An integrated liquid crystal display and backlight system for generating video images for a portable computer (12) comprising a top glass (32), a bottom glass (34) and a thin film transistor and liquid crystal layer (36) disposed therebetween, a diffuser (38) bonded to the bottom glass (34) on the side opposite the top glass (32), a substrate (40) bonded to the diffuser (38) opposite the bottom glass (34) having an array of semispherical cavities (42) each having an aluminized surface (44), a phosphor layer (46) coating the aluminized surfaces (44), an array of indium tin oxide conductors (48) electrically connected to the aluminized surfaces (44) and disposed within the cavities (42), and a volume of mercury gas (50) filling the cavities (42) such that when a voltage (54) is established between the aluminized surfaces (44) and the indium tin oxide conductors (48), the phosphor (46) becomes excited and produces backlight for the liquid crystal display system (26).

Detection of glucose via electrochemiluminescence in a thin-layer cell with a planar optical waveguide

Abstract: Light generated by luminol electrochemiluminescence is coupled into a simple planar optical waveguide and is collected with a photomultiplier tube and a photon counter unit. The waveguide is mounted to a thin-layer cell which is connected to a flow injection analysis system. The waveguide is coated with indium tin oxide and modified with covalently attached glucose oxidase. The range of detection for glucose is 0-10 mM (correlation coefficient r = 0.9974), with a detection limit of 0.3 mM.

Electrical and structural properties of indium tin oxide films deposited by reactive DC sputtering

Abstract: High-quality indium tin oxide (ITO) films were deposited by reactive DC sputtering on glass and quartz substrates. Both pure H2O vapour and O2 were used as reactive sputtering atmospheres. The electrical parameters, free carrier concentration and carrier mobility as well as the resistivity of the ITO films were optically and contactlessly determined from IR reflection spectra by applying the Drude theory. Electrical properties of ITO films were examined as a function of deposition parameters, layer thickness and annealing procedures. The DC-H2O-sputtered ITO films show improved electrical properties because of a high free carrier concentration of N=6.2*1020 cm-3 immediately after deposition compared with a maximum of N=4*1020 cm-3 for DC-O2-sputtered ITO films occurring only after thermal annealing. Moreover, another annealing characteristic of DC-H2O-sputtered ITO films was detected because of their increasing resistivity during N2 annealing in contrast to DC-O2-sputtered ITO films. The low resistivity of ITO films, deposited by application of H2O as a reactive sputtering atmosphere, is due to an improvement in crystallinity and an increase in the donor level of Sn and O vacancies.

Method of manufacturing a thin silicon-oxide layer

Abstract: A description is given of a method of providing an ultra-thin (< 1 nm) silicon-oxide layer on a substrate surface, for example, of a metal. A film of a solution of a polyorganosiloxane is applied to said substrate surface. After drying, said polyorganosiloxane is completely converted to said silicon-oxide layer by means of an UV-ozone treatment. Such an ultra-thin silicon-oxide layer sufficiently protects a metal surface against corrosion. In addition, said silicon-oxide layer can be silanized with the customary silane coupling agents to improve the bond with polymers. The method can very suitably be used, for example, to treat metal leadframes for ICs and to provide a bonding layer for indium tin oxide on polyacrylate for a passive plate of LC displays.

Fabrication of carbon tetrachloride gas sensors using indium tin oxide thin films

Abstract: Indium tin oxide (ITO) polycrystalline thin films grown on alumina substrates by the thermal evaporation technique are used for fabricating gas sensors to detect carbon tetrachloride (CCl4). The electrical conductance of the sensors appears to increase and decrease on exposure to gaseous CCl4, depending on the operating temperature. The thin-film gas sensors with a thickness of about 100 nm shows a maximum sensitivity when operated at 448 K for various concentrations of CCl4. A tentative mechanism is proposed for the role of CCl4 gas in increasing and decreasing the conductance of ITO thin-film gas sensors with changes of operating temperature.

Growth of Indium‐Tin‐Oxide Thin Films by Atomic Layer Epitaxy

Abstract: Transparent and conducting indium-tin-oxide (ITO) finds use in numerous thin-film applications, e.g., as transparent electrodes in flat panel displays and electrochromic windows, as active and passive components in photovoltaic devices, and as long infrared wavelength (IR) radiation reflecting heat mirror layers in energy efficient windows. Indium-tin-oxide thin films were deposited by atomic layer epitaxy at 500 C using InCl{sub 3}, SnCl{sub 4}, and water as precursors. The films were characterized by means of X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, polarography, and by optical and electrical measurements. The films had polycrystalline In{sub 2}O{sub 3} structure. In addition, the SnO{sub 2} phase was detected in films containing the highest tin contents. High transparencies and resistivities in the order of 2.4{times}10{sup {minus}4} {Omega}cm could be achieved by optimizing the tin doping procedure. Postannealing decreased the resistivity about 5%.

Method for forming a semiconductor device

Abstract: According to a transparent conductive film forming method, after an ITO (Indium Tin Oxide) thin film is formed at room temperature by a sputtering method, an annealing treatment is conducted on the film under hydrogen atmosphere at a suitable temperature such as a temperature higher than 200° C

Thin film solar cell

Abstract: This invention relates to a thin film solar cell which improves bonding strength and reflectivity of a back electrode layer, and provides two kinds of structures The first of them provides a thin film solar cell produced by sequentially laminating a transparent electrode layer, a thin film semiconductor layer and a back electrode layer on an insulating transparent substrate, wherein the back electrode layer comprises a first transparent conductive metal compound layer having a lower refractive index than the semiconductor that constitutes the thin film semiconductor layer, a second transparent conductive metal compound layer and a metal layer, and the second transparent conductive metal compound layer contains the constituent components of at least one of the first transparent conductive metal compound layer and the metal layer Preferably, the first transparent conductive metal compound layer is made of a metal oxide, more concretely one of indium tin oxide, tin oxide and zinc oxide When a compound semiconductor is used for the thin film semiconductor layer, cadmium sulfide can be used for the first transparent conductive metal compound layer The second thin film solar cell is a thin film solar cell produced by sequentially laminating a transparent electrode layer, a thin film semiconductor layer and a back electrode layer on an insulating transparent substrate, wherein the back electrode layer comprises a laminate of an intermediate thin layer containing silver, oxygen and constituent metal elements of a transparent conductive metal oxide and a silver thin film, and zinc is particularly suitable for the constituent metal element of the transparent conductive metal oxide

Efficient electroluminescence of distyrylarylene with hole transporting ability

Abstract: We report that organic electroluminescence devices with a hole transporting emitting layer composed of distyrylarylene derivatives realized highly efficient and bright emission in the blue‐green region. Luminous efficiency was obtained to be 2.1 lm/W in the low‐luminance region (135 cd/m2) using an indium tin oxide/emitting layer/electron transporting layer/Mg:Ag structure. The external quantum efficiency was estimated to be about 1.5%. The highest luminance was obtained to be 4000 cd/m2 for the device.

AlGaInP LEDs using reactive thermally evaporated transparent conducting indium tin oxide (ITO)

Abstract: Reactive thermally evaporated transparent conducting indium tin oxide (ITO) layers are used as window material and for current spreading layers on AlGaInP light emitting diodes (LEDs). The sheet resistance of the ITO films deposited is of the order of 4.5 /spl Omega///spl square/ with up to 90% transmission in the visible region of the spectrum. In all cases, the devices incorporating the ITO layer gave a marginally greater output (10%) than the standard non-ITO devices.

Photovoltaic Properties of Screen‐Printed CdTe / CdS Solar Cells on Indium‐Tin‐Oxide Coated Glass Substrates

Abstract: Screen-printed CdTe/CdS solar cells were fabricated on glass and indium-tin-oxide (ITO) coated glass substrates, and their photovoltaic and electrical properties were analyzed. The CdTe/CdS/ITO cells showed efficiencies of 8.6--8.9%, a level which is 1--4% higher than efficiencies of cells without ITO. The higher efficiencies were caused by higher fill factor (FF) values. However, the FF values of the CdTe/CdS/ITO cells are considerably lower than those expected from the relatively low sheet resistances (11--13 {Omega}/{open_square}) of the CdS/ITO window layers. Further, the CdTe/CdS/ITO cells showed lower open-circuit voltages and unimproved short-circuit current densities when compared with the cells without ITO. This was evident despite the high transmittances of the CdS/ITO window layers relative to those of the CdS window layers over the wavelength range from 520 to 900 nm. The electrical analyses indicated that the lower photovoltaic parameters of the CdTe/CdS/ITO cells originated from a degraded junction, possibly due to the diffusion of the elements (In, O, and Sn) from the ITO layer through the CdS layer into the junction region.