Patents Assigned to Watkins-Johnson Company
  • Patent number: 5786278
    Abstract: A method of converting tensile stress in an APCVD oxide film at low temperature to compressive stress. The oxide film is subjected to pressures above atmospheric pressures and temperatures below the atmospheric pressure conversion temperature. This enables films to be converted to compressive stress without thermal damage to the underlying integrated circuit.
    Type: Grant
    Filed: August 27, 1996
    Date of Patent: July 28, 1998
    Assignee: Watkins-Johnson Company
    Inventor: H. Wallace Fry
  • Patent number: 5768268
    Abstract: An open-architecture digital cellular base station readily adapted to support communication over a variety of air interface standards is disclosed herein. The base station includes a wideband digital transceiver system having transmit and receive sections. Within the transmit section, an input line interface operates to couple a plurality of input information signals onto a time-division multiplexed (TDM) transmit bus. A plurality of digital transmitter modules are coupled to the TDM transmit bus, each of the digital transmitter modules generating a set of digital baseband signals in response to a corresponding set of the plurality of input information signals. The set of digital information signals are applied to a wideband summation network disposed to sequentially add the set of digital information signals into a wideband data stream. A wideband transmitter then generates a wideband transmission waveform using the wideband data stream.
    Type: Grant
    Filed: July 19, 1995
    Date of Patent: June 16, 1998
    Assignee: Watkins Johnson Company
    Inventors: Paul A. Kline, Timothy J. Harris, Henry W. Anderson
  • Patent number: 5752181
    Abstract: Apparatus for reducing intermodulation distortion in a mixer output signal provides for back-to-back serial connected FET transistors joined at gate and source terminals and cancels intermodulation distortion. In one embodiment the apparatus provides first and second FET having their gates tied to one another and their sources tied to one another such that the FETs are connected back-to-back in series and have equal gate-to-source voltages and FET drain-to-source voltage that are equal in magnitude but opposite in sign to the second FET drain-to-source voltage. A control voltage, such as a local oscillator voltage signal is applied between the FET gate terminals and the FET source terminals to switch the conduction state of the serially connected FETs between a conducting state and a non-conducting state.
    Type: Grant
    Filed: December 18, 1995
    Date of Patent: May 12, 1998
    Assignee: Watkins-Johnson Company
    Inventor: Michael W. Vice
  • Patent number: 5745328
    Abstract: An electrical impulse suppressor comprising a band pass filter formed with strip transmission lines adapted to attenuate the flow of energy therethrough above and below a band limited range of frequencies. The suppressor used the impedance of a discharge means connected to a strip transmission live element to form the first of two resonant circuits used in the construction of the band pass filter.
    Type: Grant
    Filed: March 3, 1997
    Date of Patent: April 28, 1998
    Assignee: Watkins-Johnson Company
    Inventor: John V. Bellantoni
  • Patent number: 5732345
    Abstract: A double balanced dual-quad transformer dual field effect transistor (FET) mixer is disclosed using a first and second (FET) which have their gates electrically connected together, such that the first and second FET are connected in series. The mixer achieves improved isolation by using a first and second diplexer, and an RF and IF coupling network which comprises a flux-coupled IF transformer and a transmission line RF balun.
    Type: Grant
    Filed: December 20, 1995
    Date of Patent: March 24, 1998
    Assignee: Watkins-Johnson Company
    Inventor: Michael W. Vice
  • Patent number: 5708556
    Abstract: An electrostatic support system for retaining a wafer. The support system generally includes a support body having a support surface for retaining said wafer, a voltage source coupled to the support body for electrostatically coupling the wafer to the support surface, and a cooling system for cooling the wafer. A plurality of arm members extend from the support body to a carriage assembly for releasably mounting the support body to the processing chamber with the support body and the arm members separated from the chamber floor. This invention also includes the method of supporting a wafer in a processing chamber which includes the steps of positioning the wafer on a wafer supporting surface, applying a voltage to an electrode assembly to electrostatically attract the wafer to the support surface and, after processing the wafer, substantially grounding the electrode assembly to sufficiently deactivate the electrostatic charge for release of the wafer from the support surface.
    Type: Grant
    Filed: July 10, 1995
    Date of Patent: January 13, 1998
    Assignee: Watkins Johnson Company
    Inventors: Ron van Os, Eric D. Ross
  • Patent number: 5696474
    Abstract: A high frequency hermetically sealed electrical feed through connector extending through an electronic device package for efficiently coupling a signal transmitted through the connector. The connector feeds through an opening in the wall of the package, and generally comprises three coaxial transmission line sections, the first line section being defined by a section of the wall opening having a predetermined diameter, an axial lead and a dielectric sleeve. The second line section is defined by the axial lead and a section of the wall having a larger diameter than the predetermined diameter. The third line section is defined by the axial lead and a section of the wall having a reduced diameter.
    Type: Grant
    Filed: December 22, 1995
    Date of Patent: December 9, 1997
    Assignee: Watkins-Johnson Company
    Inventors: Thomas Paul Spivey, Jeffrey Charles Allard, John Vincent Bellantoni
  • Patent number: 5678226
    Abstract: A unbalanced mixer capable of operation in the absence of DC bias is disclosed herein. The mixer includes an input or local oscillator (LO) port for receiving an input signal. A first transistor has a control terminal coupled to the mixer input port, and an output terminal coupled to a first signal port of the mixer. The mixer further includes a resonator circuit, connected between the transistor control and output terminals, for providing signal isolation between the mixer input port and the first signal port. In a preferred implementation the resonator circuit comprises an inductive element in parallel with a first intrinsic capacitance of the transistor. The mixer may also include a diplexer circuit for coupling signal energy of a first frequency between the output terminal and the first signal port, and for coupling signal energy of a second frequency between the output terminal and a second signal port.
    Type: Grant
    Filed: November 3, 1994
    Date of Patent: October 14, 1997
    Assignee: Watkins Johnson Company
    Inventors: Xiaohui Li, Michael Wendell Vice
  • Patent number: 5668063
    Abstract: A method of planarizing a layer of material having a pre-determined thickness above a circuit feature on a semiconductor device is provided. A first layer of material is formed atop the surface of the semiconductor substrate and circuit feature to a pre-determined thickness. A thin, continuous trace layer of doped silicon oxide material is formed atop the first layer, and then a second layer of material is formed atop the trace layer. The second layer is planarized, and planarization is terminated upon reaching the trace layer, thereby providing a semiconductor with a planar layer.
    Type: Grant
    Filed: May 23, 1995
    Date of Patent: September 16, 1997
    Assignee: Watkins Johnson Company
    Inventors: Howard Wallace Fry, Kurt James Lightfoot
  • Patent number: 5652179
    Abstract: Disclosed is a method of fabricating semiconductor devices having sub-micron gate electrodes using angle and direct evaporation techniques. A first and second photoresist layer are formed atop a substrate and the second layer is selectively processed to form an edge with a well controlled profile. A first metal is evaporated at a first angle and the edge of the second photoresist layer shields a portion of the first photoresist layer form metal deposition which defines a patterned opening of desired width. The patterned opening is now etched in a well controlled manner to expose a portion of the active channel region of the device, and a desired height is defined by the distance from the first metal layer to the exposed channel region. A second layer is deposited by evaporation at a second angle thereby forming a plug in the channel region wherein placement of one edge of the plug is determined by the height and the second angle.
    Type: Grant
    Filed: April 24, 1996
    Date of Patent: July 29, 1997
    Assignee: Watkins-Johnson Company
    Inventors: Walter Andrew Strifler, Carol Yu-Bin Lee, William Robert Hitchens, Ronald David Remba
  • Patent number: 5639343
    Abstract: The present invention comprises a method of characterizing a group III-V epitaxial semiconductor wafer in a characterization profiling apparatus having an electrolytic cell. The wafer contains at least a Group III-V compound first-layer and a thin etch stop layer atop of the first layer and at least one second layer atop of the etch stop layer having a differing composition from the etch stop layer. The wafer is placed in the electrolytic cell and the surface of the at-least second layer is etched with a citrate buffer solution of citric acid and a salt of citric acid under anodic bias conditions. The etchant is highly selective and etching terminates upon reaching the etch stop layer. A Schottky diode is formed between the wafer and the solution, and the wafer is characterized in situ by performing capacitance-voltage measurements which are evaluated to determine the threshold voltage of the semiconductor wafer.
    Type: Grant
    Filed: December 13, 1995
    Date of Patent: June 17, 1997
    Assignee: Watkins-Johnson Company
    Inventor: Daniel Mark Dobkin
  • Patent number: 5629654
    Abstract: A coplanar waveguide coupler comprises traces and waveguides, all formed on one layer of multi-layer printed wiring board with the interconnects between said waveguide coupler traces and waveguides are carried on a second layer of said board. A third layer may have a ground plane.
    Type: Grant
    Filed: May 6, 1996
    Date of Patent: May 13, 1997
    Assignee: Watkins-Johnson Company
    Inventor: Eric A. Frick
  • Patent number: 5613859
    Abstract: A connector assembly for detachably connecting a coaxial transmission line to a micro-strip lead formed on a printed wiring board is disclosed.
    Type: Grant
    Filed: November 28, 1995
    Date of Patent: March 25, 1997
    Assignee: Watkins-Johnson Company
    Inventors: John V. Bellantoni, John S. Tobias
  • Patent number: 5551074
    Abstract: A mixer comprising four FET transistors in a MMIC, a reflection transformer having tri-filar windings, an IF balun, an RF balun, a local oscillator balun, a pair of load resistors, a pair of series resistors, and a pair of series capacitors. The mixer is packaged in a lidded header similar to a large TO-8 metal package.
    Type: Grant
    Filed: January 19, 1995
    Date of Patent: August 27, 1996
    Assignee: Watkins-Johnson Company
    Inventor: Michael W. Vice
  • Patent number: 5454928
    Abstract: A method of forming solid metal vias extending between the top and bottom surfaces of a substrate with the ends of the vias being substantially coplanar with the top and bottom surfaces. The method includes the steps of forming holes through the substrate, plating the interior of the holes with excess metal to fill the holes and extend beyond the ends of the holes, heating the substrate to cause the metal to melt and consolidate to form solid vias with domed ends, and lapping the top and bottom surfaces of the substrate to remove the domes. Conductive layers may then be formed over the vias. These layers may have windows over a portion of each via to provide an escape route for expanding fluids during further processing of the substrate.
    Type: Grant
    Filed: January 14, 1994
    Date of Patent: October 3, 1995
    Assignee: Watkins Johnson Company
    Inventors: Michael R. Rogers, Theodore E. Washburn, Michael A. Novice, Ronald S. Besser, Brian S. White
  • Patent number: 5414313
    Abstract: A dual-mode successive detection amplifier for providing a first output signal corresponding to a logarithmic function of a RF input signal, and for providing a second limited RF output signal is disclosed herein. A RF input signal is applied to the first of a succession of amplification stages arranged along a RF signal path to cascade amplify the RF input signal into the limited RF output signal. A plurality of detector/limiter (D/L) circuits interposed between the amplification stages limit RF signal energy propagating along the RF signal path so as to prevent saturation of the amplification stages. The D/L modules also provide a succession of detection signals corresponding to video envelopes of the RF signal energy produced by each of the amplification stages. The detection signals are applied to a video summation line and therein summed to produce the logarithmic output signal.
    Type: Grant
    Filed: February 10, 1993
    Date of Patent: May 9, 1995
    Assignee: Watkins Johnson Company
    Inventors: Emil J. Crescenzi, Jr., Jonathan K. Bamford, Titus J. Wandinger, Michael A. O'Mahoney
  • Patent number: 5377300
    Abstract: A heater for heating processing gases used in semiconductor processing equipment; the heater including a chamber whose walls are heated by a strip heater whereby gases flowing through the chamber are heated by said heated walls.
    Type: Grant
    Filed: November 4, 1992
    Date of Patent: December 27, 1994
    Assignee: Watkins-Johnson Company
    Inventors: Craig C. Collins, Eric A. Ahlstrom
  • Patent number: 5374328
    Abstract: A solution of hydrogen peroxide [H.sub.2 O.sub.2 ], citric acid [HOC(CH.sub.2 COOH).sub.2 COOH.H.sub.2 O], and a salt of citric acid such as potassium citrate [HOC(CH.sub.2 COOK).sub.2 COOK.H.sub.2 O], and hydrogen peroxide [H.sub.2 O.sub.2 ], in a proper pH range, selectively etches GaAs-containing Group III-V compounds in the presence of other Group III-V compounds. As an illustration, Al.sub.y Ga.sub.1-y As is selectively etched in the presence of Al.sub.x Ga.sub.1-x As (0.ltoreq.y<0.2 & x>0.2) when the pH range of the etchant solution is between approximately 3 and 6. The etchant solution described herein may be utilized in the fabrication of, for example, high-frequency transistors exhibiting improved saturated current (I.sub.dss) and threshold voltage (V.sub.th) uniformity.
    Type: Grant
    Filed: March 25, 1993
    Date of Patent: December 20, 1994
    Assignee: Watkins Johnson Company
    Inventors: Ronald D. Remba, Paul E. Brunemeier, Bruce C. Schmukler, Walter A. Strifler, Daniel H. Rosenblatt
  • Patent number: 5341110
    Abstract: A phase-locking oscillator circuit having improved phase noise characteristics is disclosed herein. The oscillator circuit includes a tuned oscillator for providing a carrier signal at a tunable carrier frequency. The carrier signal is applied to an input port of a phase modulator operative to impress an RF signal upon output terminal. An error detection and feedback network generates an error signal by comparing a predefined characteristic of the RF output signal to a reference signal. The network includes a loop filter arrangement which operates upon the error signal so as to provide a tuned oscillator tuning signal to a tuning port of the tuned oscillator and a modulator control signal to a control port of the phase modulator. In an exemplary implementation the error detection and feedback network includes a phase detector for generating the error signal in response to the phase difference between the RF output signal and the reference signal.
    Type: Grant
    Filed: July 14, 1993
    Date of Patent: August 23, 1994
    Assignee: Watkins-Johnson Company
    Inventor: Benedict J. Nardi
  • Patent number: 5304398
    Abstract: A method for depositing silicon dioxide on the surface of a substrate or the like using a nitrogen-containing precursor is disclosed herein. In a preferred implementation the deposition is performed using an atmospheric pressure reactor, into which is directed toward the substrate surface a stream of source gas comprised of ozonated oxygen. A stream of a nitrogen-containing precursor such as, for example, hexamethyldisilazane (HMDS) is also directed into the reactor toward the substrate surface. In addition, a stream of a nitrogen-containing separator gas is directed into the reactor between the streams of precursor and source gases. The inventive deposition method has been shown to result in improved film nucleation on a variety of substrate surfaces.
    Type: Grant
    Filed: June 3, 1993
    Date of Patent: April 19, 1994
    Assignee: Watkins Johnson Company
    Inventors: Wilbur C. Krusell, James P. Garcia, Daniel M. Dobkin, Frederick F. Walker, Jose F. Casillas