Abstract: A shutter switch is disclosed and placed in the path of a millimeter beam and is either opaque or transparent to the beam. The shutter switch comprises a number of waveguides placed adjacent to one another to intercept the beam, a portion of the beam passing through each waveguide. The dimensions of each waveguide are such that transmission of the respective portion of the beam would be cut-off if all of the waveguide walls were conductive. However, the waveguides have high impedance structures on at least two of their opposing interior walls that allow the beam at the design frequency to be transmitted through the waveguide with uniform density and minimal attenuation. At this design frequency the shutter switch is essentially transparent to the beam. Each of the high impedance structures can also be changed to a conductive surfaces such that all of the waveguide walls appear conductive and the waveguide takes on the characteristics of a metal rectangular waveguide.

Abstract: A new cell assembly for semiconductor wafer electroplating in the plated-side-up configuration utilizes a narrow passageway around the perimeter of the wafer through which solution is forced so as to provide the laminar flow needed for effective Damascene copper plating. In addition, use of a cylindrical insulating cell wall whose inside diameter matches that of the wafer area being plated avoids overplating of the wafer periphery. Anode isolation in a compartment separated via a solution transport barrier prevents introduction of particulates and holds anolyte in place during wafer changes. This cell assembly is readily amendable to automated wafer plating.

Abstract: A MEMS module is provided comprising at least one MEMS device adhesively bonded to a substrate or wafer, such as a CMOS die, carrying pre-processed electronic circuitry. The at least one MEMS device, which may comprise a sensor or an actuator, may thus be integrated with related control, readout/signal conditioning, and/or signal processing circuitry. An example of a method pursuant to the invention comprises the adhesive bonding of a pre-processed electronics substrate or wafer to a layered structure preferably in the form of a silicon-on-insulator (SOI) substrate. The SOI is then bulk micromachined to selectively remove portions thereof to define the MEMS device. Prior to release of the MEMS device, the device and the associated electronic circuitry are electrically interconnected, for example, by wire bonds or metallized vias.

Abstract: A semiconductor switch includes a thyristor and a current shunt, preferably a transistor in parallel with and controlled by the thyristor, which shunts thyristor current at turn-off. The thyristor includes a portion of a drift layer, with a p-n junction formed below a gate adjacent to the drift layer to establish a depletion region with a high potential barrier to thyristor current flow at turn-off. The drift layer also provides the transistor base, as well as a current path allowing the transistor base current to be controlled by the thyristor. The switch is voltage controlled using an insulated gate.

Abstract: Test probe pads are located lateral to, and spaced from, the emitter, base or collector region of a bipolar transistor, preferably on separate pedestals, and connected to their respective transistor regions by air bridges. The probe pads, transistor contacts and air bridges are preferably formed as common metallizations. In the case of an HBT, a gap in the subcollector below the air bridges insulates the test transistor from capacitor loading by the probe pads. The test transistors can be used to characterize both themselves and functional circuit transistors fabricated with the same process on the same wafer by testing at an intermediate stage of manufacture, thus allowing wafers to be discarded without completing the manufacture if their transistors do not meet specifications.

Abstract: A heterojunction bipolar transistor (HBT) is disclosed that includes successive emitter, base and collector and sub-collector epitaxial layers and emitter, base and collector contact metals contacting the emitter, base and sub-collector layers respectively. A passivation material is included that covers the uncovered portions of the layers and covers substantially all of the contact metals. The passivation material has a planar surface and a portion of each of the contact metals protrudes from the surface. Planar metals are included on the planar surface, each being isolated from the others and in electrical contact with a respective contact metal. A method for fabricating an HBT is also disclosed, wherein successive emitter, base, collector and sub-collector epitaxial layers are deposited on a substrate, with the substrate being adjacent to the sub-collector layer.

Abstract: A multi layered high impedance structure presents a high impedance to multiple frequency signals, with a different frequency for each layer. Each layer comprises a dielectric substrate, and an array of radiating elements such as parallel conductive strips or conductive patches on the substrate's top surface, with a conductive layer on the bottom surface of the bottommost layer. The radiating elements of succeeding layers are vertically aligned with conductive vias extending through the substrates to connect the radiating elements to the ground plane. Each layer presents as a series of parallel resonant L-C circuits to an E field at a particular signal frequency, resulting in a high impedance surface at that frequency. The new structure can be used as the substrate for a microstrip patch antenna to provide an optimal electrical distance between the resonator and backplane at multiple frequencies.

Abstract: A mechanical translator includes at least one magnet that is disposed on a substrate to carry a load and has a magnetic axis generally transverse to the substrate, establishing a magnetic field with maximum external density adjacent the substrate. An ultra low friction interface is obtained with ferrofluid bearings, such as a light mineral oil medium mixed with isoparaffinic acid, which establish a critical angle of displacement from a horizontal static position of less than 1 degree, and preferably less than 10 minutes. A controller of magnetic material can be placed on the opposite side of the substrate to control the movement of the magnets.

Abstract: A high power switch includes diode and BJT structures interdigitated in a drift layer and separated by insulated trench gates; electrodes contacting the diode and BJT structures provide anode and cathode connections. Shallow N+ regions extend below and around the corners of the oxide side-walls and bottoms of respective gates. A voltage applied across the anode and cathode sufficient to forward bias the diode's p-n junction causes electrons to be injected which provide a base drive current to the BJT sufficient to turn it on and enable current to flow from anode to cathode via the diode and BJT structures. A gate voltage sufficient to reverse bias the junction between the shallow N+ regions and the drift layer forms a potential barrier which blocks current flow through the diode and BJT structures and eliminates the base drive current such that the BJT and said switch are turned off.

Abstract: A MEMS fabrication process eliminates through-wafer etching, minimizes the thickness of silicon device layers and the required etch times, provides exceptionally precise layer to layer alignment, does not require a wet etch to release the moveable device structure, employs a supporting substrate having no device features on one side, and utilizes low-temperature metal-metal bonding which is relatively insensitive to environmental particulates. This process provided almost 100% yield of scanning micromirror devices exhibiting scanning over a 12° optical range and a mechanical angle of ±3° at a high resonant frequency of 2.5 kHz with an operating voltage of only 20 VDC.

Abstract: Friction stir processing (FSP) modifies the surface microstructure of metals so that thick-section metal workpieces can be bent over large angles without formation of surface cracks. A thick 2519-T8 aluminum plate (25.4 mm thick and 50.8 mm wide) was friction stir processed across the pre-tensile surface to a depth of 6.3 mm, and was then bent at room temperature over a punch with radius 38.1 mm into a v-shaped die to an 80° bend angle. Whereas unprocessed workpieces of this type exhibited surface cracking at 31° bend angle and failed at 40° bend angle, no cracking was evident for the friction stir processed workpiece up to 80° bend angle.

Abstract: A dynamic magnet system, particularly useful for electrical generation, employs multiple magnets in polar opposition to each other for individual movement relative to a support structure. The magnets have a critical angle of displacement from a horizontal static position of less than 1 degree, with at least some of the magnets having mutually different properties. With different magnetic strengths, a greater movement is produced for both magnets in response to movements of the support structure, for particular ranges of magnetic strength ratios, than would be the case with equal magnets. The magnet movement can be translated into an electrical signal to power an operating system. Ultra low friction ferrofluid bearings can be used to establish static coefficients of friction between the magnets and support structure less than 0.02, enabling useful power generation from only slight movements of the support structure.

Abstract: An inexpensive polyimide-free alignment layer comprising a mixture of an epoxy and a reactive liquid crystal material is used for fabricating liquid crystal displays (LCDs). The alignment layer can be cast onto a previously aligned layer, without destroying the alignment of the underlying layer, thus allowing for monolithic fabrication of compensator stacks, without film transfer lamination.

Abstract: A mechanical translator includes at least one magnet that is disposed on a substrate to carry a load and has a magnetic axis generally transverse to the substrate, establishing a magnetic field with maximum external density adjacent the substrate. An ultra low friction interface is obtained with ferrofluid bearings, such as a light mineral oil medium mixed with isoparaffinic acid, which establish a critical angle of displacement from a horizontal static position of less than 1 degree, and preferably less than 10 minutes. A controller of magnetic material can be placed on the opposite side of the substrate to control the movement of the magnets.

Abstract: An electrical generator includes one or more magnets that move relative to one or more conductors to generate an electrical signal in each conductor. Each magnet has ferrofluid bearings in the vicinity of its opposite ends to provide a low friction interface between the magnet and a support structure. The ferrofluid bearings establish a field expansion medium that directs at least a portion of the magnetic field so that a greater portion of the field intersects the conductors than in the absence of the medium. The magnet aspect ratio is preferably on the order of unity.

Abstract: A testing apparatus for determining the etch bias associated with a semiconductor-processing step includes a substrate, a first cathode finger with a first width on the substrate, a second cathode finger with a second width on the substrate, and a cathode large area on the substrate wherein the cathode large area has a third width W″ and a length L″ that are both substantially larger than either of the first and second widths.

Abstract: An electrical generator includes a magnet constrained to move relative to a conductor by a support structure, with a ferrofluid bearing providing an ultra low friction interface between the magnet and support structure. The assembly has a critical angle of displacement from a horizontal static position of less than 1 degree, and preferably less than 10 minutes. An electrical signal is generated in the conductor by the moving magnetic field.

Abstract: A dynamic magnet system, particularly useful for electrical generation, employs multiple magnets in polar opposition to each other for individual movement relative to a support structure. The magnets have a critical angle of displacement from a horizontal static position of less than 1 degree, with at least some of the magnets having mutually different properties. With different magnetic strengths, a greater movement is produced for both magnets in response to movements of the support structure, for particular ranges of magnetic strength ratios, than would be the case with equal magnets. The magnet movement can be translated into an electrical signal to power an operating system. Ultra low friction ferrofluid bearings can be used to establish static coefficients of friction between the magnets and support structure less than 0.02, enabling useful power generation from only slight movements of the support structure.

Abstract: An electrical generator includes a magnet constrained to move relative to a conductor by a support structure, with a ferrofluid bearing providing an ultra low friction interface between the magnet and support structure. The assembly has a critical angle of displacement from a horizontal static position of less than 1 degree, and preferably less than 10 minutes. An electrical signal is generated in the conductor by the moving magnetic field.

Abstract: The present invention provides a system and method for controlling leading edge contamination and crossflow instabilities for laminar flow on aircraft airfoils that is lightweight, low power, economical and reliable. Plasma surface discharges supply volumetric heating of the supersonic boundary layers to control the Poll Reynolds number and the cross flow Reynolds number and delay transition to turbulent flow associated with the leading edge contamination and crossflow instabilities. A closed-loop feedback control system that incorporates these principles includes three primary components: heat-flow sensors, a PID controller, and plasma discharge elements. Heat-flow sensors distributed around the airfoil surface provide root-mean-square (rms) pulsations of the heat flow to the airfoil skin.