Abstract: An electroluminescent display includes a transparent electrode (4) and a metal assist structure (6) formed over a portion of the transparent electrode (6) such that the metal assist structure (6) is in electrical contact with the transparent electrode (4). The metal assist structure (6) includes a first refractory metal layer (10), a primary conductor layer (12) formed on the first refractory metal layer (10), and a second refractory metal layer (14) formed on the primary conductor layer (12). The first and second refractory metal layers (10, 14) are capable of protecting the primary conductor layer (12) from oxidation when the electroluminescent display is annealed to activate a phosphor layer (18). In an alternate embodiment, an electroluminescent display includes a substrate (2) and a metal electrode (22) formed on the substrate (2).

Abstract: An electroluminescent display includes a transparent electrode (4) and a metal assist structure (6) formed over a portion of the transparent electrode (6) such that the metal assist structure (6) is in electrical contact with the transparent electrode (4). The metal assist structure (6) includes a first refractory metal layer (10), a primary conductor layer (12) formed on the first refractory metal layer (10), and a second refractory metal layer (14) formed on the primary conductor layer (12). The first and second refractory metal layers (10, 14) are capable of protecting the primary conductor layer (12) from oxidation when the electroluminescent display is annealed to activate a phosphor layer (18). In an alternate embodiment, an electroluminescent display includes a substrate (2) and a metal electrode (22) formed on the substrate (2).

Abstract: A novel heterostructure acoustic charge transport (HACT) device is disclosed having an optimized charge density. The device includes a transducer fabricated on a substrate structure that launches surface acoustic waves. A reflector is formed in the substrate structure at an end portion adjacent to the transducer for reflecting the surface acoustic Waves. Also included is an electrode configured with the transport channel at an end thereof distal to the transducer for generating electrical signal equivalents of the propagating electrode charge. During fabrication, the resistivity of the layers initially configured at a lower than desired value. The layer is subsequently etched to raise the resistivity to the desired value.

Abstract: A monolithic integrated circuit device combines integrated heterostructure acoustic charge transport (HACT) devices and heterostructure insulated gate field effect transistor (HIGFET) devices in a single structure in which the HACT and HIGFET layers are grown in as a contiguous composite heterostructure.

Abstract: A heterojunction acoustic charge transport device (HACT) having a charge transport channel 39 which is sandwiched between upper and lower charge confinement layers, 14,20, has the charge transport channel 39 made of a Strained Layer Superlattice (SLS) comprising alternating deep-well semiconductor layers 40, that provide a deep quantum well depth, and strain relief layers 42 that provide strain relief to prevent dislocations from occurring due to lattice mismatches between the InGaAs layers within the channel 39 and the charge confinement layers 14,20, thereby allowing the overall thickness of the channel 39 to be at least as wide as conventional HACT devices that use a GaAs channel. The strain relief layers 42 may be narrowly sized to allow tunneling of electrons across the entire channel 39 thereby allowing the charge to move as a single group, or alternatively, widely sized to provide separate isolated channels thereby allowing the charge to move in separate groups.

Abstract: A novel surface acoustic wave (SAW) element for use in a stabilized oscillator circuit capable of coupling directly to external circuitry includes a pair of opposed transducers formed on a surface of a piezoelectric crystal for launching surface acoustic waves into a resonant cavity formed by opposed reflectors on the crystal surface. The element is characterized by a supplemental transducer coupled to the cavity for directly providing external circuitry with signals corresponding to the resonant surface acoustic waves.

Abstract: A one-dimensional or two-dimensional transmission mode spatial light modulator (SLM) includes two different mediums, one medium being a semiconductor comprising one or more heterojunction acoustic charge transport (HACT) channels 28 with surrounding layers 26, 30 vertically adjacent to a multiple quantum well (MQW) region 22, and the other being a transparent piezoelectric insulating substrate 10 thick enough to allow a surface acoustic wave (SAW) 13 to propagate therein. The SAW 13 is launched in the substrate 10 by a transducer 12 and generates electric fields which propagate the charge along the HACT channel 28 in the semiconductor medium 18. Electrodes 32, 34, 36 carry charge to and from the HACT channel 28, and light 40 is applied to a surface 44 perpendicular to the MQW region 22.

Abstract: A heterostructure acoustic charge transport (HACT) device having a number of signal tap electrodes has revealed unexpected insensitivity to electrode spacing and unexpected sensitivity to electrode width. Spacing of one SAW wavelength between consecutive electrodes and an electrode width of .lambda./20 are preferred.

Abstract: An acoustic charge transport device having a number of signal tap electrodes has revealed unexpected insensitivity to electrode spacing and unexpected sensitivity to electrode width. Spacing of one-half SAW wavelength between consecutive electrodes and an electrode width of .lambda./20 are preferred for low frequency response.

Abstract: A simplified heterostructure charge transport device has a GaAs transport layer that is the top layer of the device, deposited on an (Al,Ga) As barrier layer for vertical confinement of charge packets. Confinement at the top surface is provided by pinning of the conduction band surface states.

Abstract: A separated substrate acoustic charge transport device includes a surface acoustic wave (SAW) element fabricated on a piezoelectric substrate and an acoustic charge transport element fabricated on a separate semiconducting substrate. The substrates are separated by a small gap such that the evanescent electric field associated with the propagating SAW wave extends into a transport channel in the acoustic charge transport element to provide for longitudinal charge confinement and transport along the transport channel.

Abstract: An improved acoustic charge transport device having an acoustic wave passing through a piezoelectric semiconductor is improved by utilizing heterostructure Quantum-wells for confining charge packets.

Abstract: A method of manufacturing surface acoustic wave devices includes providing a dielectric substrate with a plurality of channels which open onto a substrate surface region and each of which accommodates a metallic electrode, the electrodes being recessed below the substrate surface region by an actual distance which at least equals a desired distance at which the electrodes have a minimum acoustic reflectivity, testing the performance of the device to ascertain at least the acoustic reflectivity of the electrodes, and etching at least the dielectric substrate, when it is ascertained during the testing that the acoustic electrode reflectivity is excessive, at least at the substrate surface region to a predetermined etching depth. The use of this method results in a device having reduced post-etching acoustic electrode reflectivity as a result of the thus obtained reduction in the difference between the actual and desired distances.

Abstract: A novel heterojunction acoustic charge transport device (HACT) includes a modulation doped field effect transistor (MODFET) on the same substrate. The device is characterized by a sequence of epitaxial layers such that the MODFET is fabricated in a first portion of the uppermost layers while the HACT device is fabricated in an adjacent second portion using a partially overlapping subset of the lower layers after selected upper ones have been removed to form a single integrated electro-acoustic device.

Abstract: A separated substrate acoustic wave device having an active piezoelectric substrate and a separate base substrate. Input and output transducers are mounted upon the base substrate. The active substrate, which includes grooved-array reflectors in the case of resonators, is mounted opposite the base substrate so that it does not contact the transducer electrodes and further so that electric fringing fields generated in the transducers will induce an acoustic wave due to the piezoelectric effect in the active substrate. Similarly, acoustic waves propagating in the active piezoelectric substrate will have an associated electric field which induces an electrical signal in the transducer permitting detection of the acoustic waves propagating in the active substrate.

Abstract: A method for trimming the resonant frequency of fabricated SAW devices. The resonant frequency of SAW devices of the type having a substrate with structures made of a second material, other than the substrate material, upon its surface, is decreased by removing quantities of the substrate material until the desired change in frequency is obtained. In one embodiment, the substrate material of the SAW device is removed by etching the substrate in a fluorocarbon plasma, which leaves the structure made of the second material substantially unchanged. In a second embodiment, the resonant frequency of SAW resonators is increased by heating the SAW device at a temperature in excess of 250.degree. C. until the desired change in resonant frequency is obtained.

Abstract: Preferred reflective surface wave processors employ cooperating serially disposed reflector sections. At least one reflecting section comprises an array of non-segmented reflecting grooves in which certain grooves are omitted to form a withdrawal array. Cooperatively coupled to this non-segmented array is an array of segmented grooves. The elements of the segmented array may be made up of progressively fewer segments in regularly spaced lines. The segments in any one segmented line may selectively be of equal lengths randomly spaced within a given line.

Abstract: A multiple track acoustic surface wave filter processes input signals successively flowing in coupled resonant acoustic tracks, each track being realized between pairs of surface wave reflectors in the surface of a planar piezoelectric substrate. The acoustic surface wave reflection and coupling devices are at least partially integrated so as to reduce the length of the structure.

Abstract: A multiple track acoustic surface wave filter processes input signals successively flowing in coupled resonant acoustic tracks, each track being realized between pairs of surface wave reflectors in the surface of a planar piezoelectric substrate.