Showing papers on "Barrier layer published in 1987"

Contact plug and interconnect employing a barrier lining and a backfilled conductor material

Abstract: A stable, low resistance contact is formed in a contact hole (16) through an insulating layer (14), e.g., silicon dioxide, formed on a surface of a semiconductor substrate (12), e.g., silicon, to a portion of a doped region (10) in said semiconductor surface. The contact comprises (a) an adhesion and contacting layer (18) of titanium formed along the walls of the insulating layer and in contact with the portion of the doped region; (b) a barrier layer (20) formed over the adhesion and contacting layer; and (c) a conductive material (22) formed over the barrier layer and at least substantially filling said contact hole. A patterned metal layer (26) forms an ohmic contact interconnect to other devices and external circuitry. The adhesion and contacting layer and barrier layer are either physically or chemically vapor deposited onto the oxide surface. The conductive layer comprises one of CVD or bias sputtered tungsten, molybdenum or in situ doped CVD polysilicon. The contact of the invention avoids the problems of encroachment at the oxide-silicon interface and worm holes associated with other contact schemes but retains process simplicity.

Multilayer interconnection for integrated circuit structure having two or more conductive metal layers

Abstract: Construction of a novel multilayer conductive interconnection for an integrated circuit having more than one conductive layer is disclosed comprising a lower barrier layer which may be in contact with an underlying silicon substrate and comprising a material selected from the class consisting of TiW and TiN; an intermediate layer of conductive metal such as an aluminum base metal; and an upper barrier layer which may be in contact with a second aluminum base metal layer and which is selected from the class consisting of TiW, TiN, MoSi x and TaSi where x equals 2 or more.

Semiconductor device using copper metallization

Abstract: A semiconductor device comprises a silicon substrate, an insulating film in which a contact hole is formed, a metallic layer deposited on said silicon substrate through the contact hole, for forming an ohmic contact to the silicon substrate, a barrier layer deposited on the metallic layer, for preventing reaction and interdiffusion between copper and silicon, and a metallization film including at least copper deposited on the barrier layer.

Heterojunction and dual channel semiconductor field effect transistor or negative transconductive device

Abstract: A heterojunction semiconductor device which has a dual channel with a high mobility layer, a barrier layer and a low mobility layer. The barrier layer is thin enough for the carriers to pass from the low mobility layer to the high mobility layer by tunnel effect, during variations of the polarization electrical field of the dual channel. The device can be used as field effect transistors with a quick response time, without variation in the charge of the channel but with a variation in the mobility of the carriers; or as negative transconductance devices for oscillators or complementary transistors in integrated circuits.

Electrophotographic photosensitive member.

Abstract: The photoconductive layer (3) has a triple-layer structure comprised of an upper layer (33) made of amorphous silicon containing germanium and carbon incorporated thereinto, a middle layer (32) made of amorphous silicon containing germanium incorporated thereinto, and a lower layer (31) made of amorphous silicon. The upper layer (33) formed between a surface layer (4) and the middle layer (32), and the lower layer (31) formed between the middle layer (32) and a barrier layer (2) serve to reduce the energy difference and the interfacial state between respective two layers respectively. High electrophotographic sensitivity for a longer wavelength light can be obtained. The sensitivity in the oscillation wavelength of the CaAlAs diode laser is improved.

Tablet for pharmaceutical use able to release active substances at successive times

Abstract: A tablet for pharmaceutical use able to release active substances at successive times, comprising at least; a first layer containing a portion of the active substance with suitable excipients, a barrier layer of polymer material gellable and/or soluble in water and/or aqueous liquids, which is interposed between said first layer and a third layer containing the remaining portion of active substance with suitable excipients, said barrier layer and said third layer being housed in a casing consisting of polymer material impermeable and insoluble in water or soluble in an alkaline environment. That part of the active substance not inserted in the casing is immediately available for dissolving, whereas the part inserted in the casing is available only after dissolution or rupture of the barrier layer and/or after solubilization of the casing.

Non-laminate thermosensitive, pressure sensitive label and method of manufacture

Abstract: A thermosensitive pressure sensitive label is provided which includes a substrate, a thermosensitive layer on one side of the substrate and a pressure sensitive adhesive layer disposed on an opposite side of the substrate. A barrier layer on top of the thermosensitive layer is covered with a silicone layer which enables the label to be rolled upon itself and unrolled without the use of a conventional backing sheet. In addition, the silicone layer enables color images formed in the thermosensitive layer to have a greater image density than the image density of color images that can be formed in the thermosensitive layer without the silicone layer being disposed thereover.

Semiconductor device with a wiring layer having a good step coverage at contact holes

Abstract: Step coverage of wiring layer (ll) of semiconductor device especially at the contact holes (5, 6) is improved. Inside of the contact holes (5, 6) is covered by polysilicon layer (7, 8, 9) deposited by chemical vapor deposition (CVD); and selectively doped with impurities having same conductivity type of the contact region (2, 3) to which the polysilicon layer (7, 8, 9) is contacted at the bottom of the contact holes (5, 6). The remaining parts of the contact holes (5, 6) are buried with SiO₂, and the wiring layer (ll) is formed on it. Since the step coverage of the material deposited by CVD is very good, the disconnection at the side walls of the contact holes (5, 6) is avoided. The short circuits caused by growth of spikes of eutectic of silicon and aluminium is also avoided. If the surface of the polysilicon layer (7, 8, 9) is covered by a thin film (2l) of SiO₂ or Si₃N₄, the material to bury the contact hole (5, 6) may be replaced by other material polysilicon or amorphous silicon for instance. Further a barrier layer (23) is provided between the wiring layer (ll) and the polysilicon layer (7, 8, 9). This prevents the migration of aluminium over the polysilicon, so the reliability of the wiring is further improved. The barrier layer (23) is made from silicide of high melting point metal or the metal itself. This improves the conduction between the contact region and the wiring layer.

Method for the production of a titanium/titanium nitride double layer

Abstract: A method for producing consecutive layers of titanium and titanium nitride on a substrate to produce a contact and barrier layer between, for example, aluminum and silicon surfaces or silicide surfaces utilizing cathode sputtering in a one chamber magnetron sputtering system. The titanium and titanium nitride layers each occur as a plurality of individual layers formed in a cyclical process with temperature treatments being carried out between the deposition of the individual layers. During the deposition of the titanium nitride layer, the nitrogen concentration in the reaction gas is adjusted higher than that stoichiometrically required for production of titanium nitride. The resulting combined layers provide low mechanical stressing, good thermal stability, low contact resistance and similar advantages. The method may be employed for the production of megabit-DRAM cells and logic circuits.

Thin film medium for horizontal magnetic recording having an improved cobalt-based alloy magnetic layer

Abstract: An improved thin film metal alloy media for horizontal magnetic recording has a magnetic layer of an alloy comprising cobalt, platinum and chromium, where the chromium concentration in the alloy is greater than 17 at% The media exhibits unexpectedly high signal-to-noise ratio (SNR) and minimal time jitter, thereby resulting in a media which is capable for use at high linear recording density The media also exhibits excellent corrosion resistance because of the chromium present in the alloy, thereby eliminating the need for a barrier layer between the magnetic layer and the protective overcoat

Laminated closure for a plastic container

Abstract: This relates to a closure for a plastic container wherein the closure is to be heat bonded to the container. The closure is of a laminated construction and includes an outer structural layer of plastic material, a combined electric heat inductive and barrier layer, and an inner bond forming plastic material layer. The bond forming inner layer is thin as compared to the thickness of the structural outer layer. The barrier layer is formed of a metal foil, preferably aluminum, and is also quite thin.

Thermoplastic multi-layer barrier packaging film and bags made therefrom

Abstract: Disclosed is a multi-layer heat-shrinkable (oriented) film having a barrier layer of polyvinylidene chloride copolymer and having an outer layer of polyamide. The polyamide layer is directly adhered to the barrier layer. Also disclosed is a method to make the film and barrier bags made therefrom.

Scalable fuse link element

Abstract: A fuse link (50) is formed using a method which offers greater scalability of the general conductor system used to wire the device. An oxide mask (36) having the shape of a desired fuse link is formed over a thin metallization layer (34). A barrier layer (38) is formed over the thin metallization layer (34). A conductive layer (40) is formed over the barrier layer (38). A photoresist mask (42) supplied to the conductive layer (40), and the conductive layer is etched to formed interconnects (44, 46). Subsequently, the barrier layer (38) and thin metallization layer (34) are etched, thus rendering a fuse link (50) between interconnects (44, 46) under the oxide mask (36).

Thin film platinum resistance thermometer with high temperature diffusion barrier

Abstract: A thin film platinum resistance thermometer capable of operation at elevated temperatures includes a benign dielectric layer (24) covering the thin film platinum resistance temperature sensing element (14) and a barrier layer (26) overlying the dielectric layer (24). The barrier layer (26), which is preferably titanium dioxide, resists diffusion or contaminants which would alter the electrical characteristics of the sensing element (14), while permitting diffusion of oxygen through the barrier layer (26).

Quantum Well Width Dependence of Negative Differential Resistance of In0.52Al0.48As/In0.53Ga0.47As Resonant Tunneling Barriers Grown by MBE

Abstract: The effect of quantum well width on the negative differential resistance (NDR) at 77 K of an InAlAs/InGaAs resonant tunneling barrier structure, lattice-matched to InP substrates and grown by MBE, was studied. The best NDR characteristics ever reported (peak-to-valley ratio of 11.4 with peak current density of 5.5×104 A/cm2) have been achieved for a resonant tunneling barrier diode with a thin quantum well width of 44 A. A reduction of electron effective mass in the InAlAs barrier layer was also observed.

Intraband quantum well photodetector and associated method

Abstract: A fast, real time method and apparatus for long wavelength infrared photodetection employs a quantum well from which stored electrons are ejected by photoemission and replaced by electrons which tunnel through a barrier bounding one side of the quantum well. The photodetector comprises a semiconductor device having a quantum well layer separated from an emitter layer on one side by a first barrier layer and from a collector layer on the other side by a second barrier layer. The first barrier is higher than the second which in turn is higher than the Fermi level in the quantum well layer. Photons excite electrons in the quantum well to an excited state from which they flow over the second barrier to the collector layer. Electrons tunnel from the emitter through the first barrier to the quantum well at the rate at which they are depleted by photoemission so that the detector is suitable for use with high pulse rate digital communication signals.

Planarization of metal pillars on uneven substrates

Abstract: A method for forming vertical metal interconnects on a semiconductor substrate having an uneven surface comprises first forming a laminated metal structure over the entire substrate. The laminated metal structure includes a first metallization sublayer, an intermediate etch stop barrier layer, and a second metallization sublayer. Usually, a barrier layer will be formed between the substrate and the laminated metal structure. The laminated metal structure is then patterned into the desired vertical metal interconnects, which interconnects are at different elevations because of the uneven underlying surface. The vertical metal interconnects are then planarized by first applying a dielectric layer and a sacrificial layer, etching back the combined dielectric and sacrificial layers to expose only the higher vertical metal interconnects, and then selectively etching back the second metal sublayer component of the higher vertical metal interconnects. By properly choosing the thicknesses of the various layers in the laminated metal structure, vertical metal interconnects having substantially identical elevations will be created.

A Bipolar Model of the Passivity of Stainless Steel: The Role of Mo Addition.

Abstract: The passive films formed on the surface of and alloys in have been characterized by AES and variable angle XPS. It is found that additions of Mo to results in the formation of a passive film with a more highly developed interfacial barrier film composed mainly of , containing in solid solution which forms a glassy phase. In addition, the passive films were found to contain more Fe. Molybdenum appears to be present as Mo4+ and Mo6+ identified as hydrated and , apparently as . It is proposed that anions are formed in the solid state along with , which together are responsible for producing, in , a bipolar film consisting of a cation selective outer layer containing and and an intrinsically anion selective inner layer. The ion selective property of this duplex film is considered to be largely responsible for the development of the barrier layer and resisting Cl− and OH− ingress. Both of these properties provide greater resistance to break down of passivity in Cl− ion media.

Humidity insensitive photoresponsive imaging members

Abstract: A photoresponsive imaging member comprised of a supporting substrate; a barrier layer of hydrogenated amorphous silicon with dopants therein; a photoconductive layer of hydrogenated amorphous silicon; a first overcoating layer of nonstoichiometric silicon nitride; and a second overcoating layer of a silicone-silica hybrid polymer.

Tablet for pharmaceutical use with release at successive times

Abstract: A tablet for pharmaceutical use able to release active substances at successive times, comprising at least: a first layer containing a portion of the active substance with suitable excipients, a barrier layer of polymer material gellable and/or soluble in water and/or aqueous liquids, which is interposed between said first layer and a third layer containing the remaining portion of active substance with suitable excipients, said barrier layer and said third layer being housed in a casing consisting of polymer material impermeable and insoluble in water or soluble in an alkaline environment. The part of the active substance not inserted in the casing is immediately available for dissolving, whereas the part inserted in the casing is available only after dissolution or rupture of the barrier layer and/or after solubilization of the casing.

Kinetics of Open-Circuit Barrier Layer Formation on Metallic Surfaces in Aqueous Solutions

Abstract: The corrosion potential of many passive metals (e.g., Mo, Ta, Zr, Nb, Hf, Ti, Al, and Fe) was found to vary linearly towards more noble values with logarithm of time in various passivating solutions. Potential and capacitance measurements indicate formation and thickening of barrier films. A general theoretical treatment of the kinetics of barrier film formation and thickening was introduced. According to this treatment, the barrier film may grow in 2 or 3 dimensions. The 3-dimensional barrier film may grow via the dissolution-precipitation mechanism or the solid-state mechanism. In all cases, the following equations were theoretically derived: for potential, Eh=A+B log (t+t°), where A, B, and t° are constants; and for capacitance, Cm−1=A′+B′ log (t+t°). where A′ and B′ are constants. The thickness measurements may help to distinguish between 2- and 3-dimensional barrier films. Also, the variation of some experimental conditions may be considered to identify the mechanism for 3-dimensional barrie...

Field-effect transistor having a superlattice channel and high carrier velocities at high applied fields

Abstract: A field effect transistor comprises a semiconductor having a source, a drain, a channel and a gate in operational relationship The semiconductor is a strained layer superlattice comprising alternating quantum well and barrier layers, the quantum well layers and barrier layers being selected from the group of layer pairs consisting of InGaAs/AlGaAs, InAs/InAlGaAs, and InAs/InAlAsP The layer thicknesses of the quantum well and barrier layers are sufficiently thin that the alternating layers constitute a superlattice which has a superlattice conduction band energy level structure in k-vector space which includes a lowest energy Γ-valley and a next lowest energy L-valley, each k-vector corresponding to one of the orthogonal directions defined by the planes of said layers and the directions perpendicular thereto The layer thicknesses of the quantum well layers are selected to provide a superlattice L 2D -valley which has a shape which is substantially more two-dimensional than that of said bulk L-valley

Stacked metal silicide gate structure with barrier

Abstract: A gate structure for integrated circuit devices which includes a work function layer, a low resistivity layer, and an electrically conductive barrier layer between the two other layers to prevent the other two layers from intermixing. The work function controlling layer is preferably selected from the group of tungsten, molybdenum, their silicides, or a combination thereof.

Method of connecting metal conductor to ceramic substrate

Abstract: A method of connecting a metal conductor to a ceramic substrate including the steps of providing a terminal portion on the ceramic substrate, the ceramic substrate having a dielectric constant less than or equal to 7.0 units and a coefficient of thermal expansion of 5×10-6 /° C. or less, forming at least one of a buffer layer and a barrier layer overlying the terminal portion of the ceramic substrate, wherein the buffer layer consists essentially of Cu and the barrier layer consists essentially of a material selected from the group consisting of Ni, Pd, and Pt, and brazing a metal conductor to the terminal portion of the ceramic substrate through the at least one of the buffer layer and the barrier layer with an Ag-based brazing filler material.

Barrier layer ceramic dielectric capacitor containing barium plumbate

Abstract: A barrier layer ceramic capacitor and a method of making the same, using barium plumbate or modified barium plumbate as the base material. The fabricating process is a one step process requiring a maximum sintering temperature of 1000° C.

Above barrier doublets in GaAs/AlxGa1−xAs superlattices

Abstract: Doublets from optical transitions with energies greater than the barrier energy gap were observed by photoluminescence excitation spectroscopy in a series of GaAs/AlxGa1−xAs superlattices. The well width and the aluminum concentration in the barrier regions were fixed at 150 A and 22%, respectively. The barrier widths ranged from 70 to 180 A. The doublets arise from transitions between the first unconfined heavy‐hole and conduction subbands. The separation of the doublet is found to be a sensitive function of the barrier width. It corresponds to the energy difference between the transition at the Brillouin zone center and at the Brillouin zone boundary along the superlattice growth direction. Good agreement was found between the experimental data and theoretical calculations. The sensitivity of the energy splitting to the width of the barrier provides a useful analytical tool in determining this quantity, in much the same way that the confined transition energies relate to the well width.

Electrical connecting pin, especially a coil former pin, and a method for its production

Abstract: The connecting pin is preferably embedded in a plastic part and is used for the solder connection of an electrical cable (line, lead). A nickel barrier layer is initially deposited onto the pin material, which consists of a copper-tin alloy, over which nickel barrier layer an outer solder layer is arranged which is used for the connection of the electrical cable and consists of a lead-tin mixture. In order to ensure solderability despite surface damage, it is proposed to electroplate a silver intermediate layer between the inner nickel barrier layer and the outer tin-solder layer and to produce a diffusion alloy with the outer tin-solder layer by tempering the pin.

Semiconductor laser having a multiple quantum well structure doped with impurities

Abstract: In a well-known semiconductor laser, a multiple quantum well type active layer consisting of barrier layers and active layers or well layers, each of which has a thickness less than the de Broglie wavelength of electrons, is doped with an impurity, and the impurity density is made higher in the barrier layer than in the well layer. Further, in a case where the multiple quantum well active layer is held between p-type and n-type cladding layers, the well layer is undoped, the part of the barrier layer lying in contact with the well layer is undoped, and the other part of the barrier layer close to the p-type cladding layer is put into the n-conductivity type while that of the barrier layer close to the n-type cladding layer is put into the n-conductivity type. Desirably, the impurity density should range from about 1×1018 to about 1×1019 cm- 3.