Patents by Inventor Robert S. Okojie

Robert S. Okojie has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10515804
    Abstract: Use of a single alloy conductor to form simultaneous ohmic contacts (SOC) to n- and p-type 4H—SiC. The single alloy conductor also is an effective diffusion barrier against gold (AU) and oxygen (O2) at high temperatures (e.g., up to 800° C.). The innovation may also provide an effective interconnecting metallization in a multi-level metallization device scheme.
    Type: Grant
    Filed: August 6, 2018
    Date of Patent: December 24, 2019
    Assignee: United States of America as Represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 10192970
    Abstract: A simultaneous ohmic contact to silicon carbide includes a mixture of platinum, titanium, and silicon compounds deposited on a silicon carbide substrate. The silicon carbide substrate includes an n-type surface and a p-type surface.
    Type: Grant
    Filed: August 11, 2014
    Date of Patent: January 29, 2019
    Assignee: The United States of America as Represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 10184777
    Abstract: A system and method for determining a change in a thickness and temperature of a surface of a material are disclosed herein. The system and the method are usable in a thermal protection system of a space vehicle, such as an aeroshell of a space vehicle. The system and method may incorporate micro electric sensors arranged in a ladder network and capacitor strip sensors. Corrosion or ablation causes a change in an electrical property of the sensors. An amount of or rate of the corrosion or the ablation and a temperature of the material is determined based on the change of the electrical property of the sensors.
    Type: Grant
    Filed: August 22, 2017
    Date of Patent: January 22, 2019
    Assignee: The United States of America as Represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 10067025
    Abstract: A modular apparatus for attaching sensors and electronics is disclosed. The modular apparatus includes a square recess including a plurality of cavities and a reference cavity such that a pressure sensor can be connected to the modular apparatus. The modular apparatus also includes at least one voltage input hole and at least one voltage output hole operably connected to each of the plurality of cavities such that voltage can be applied to the pressure sensor and received from the pressure sensor.
    Type: Grant
    Filed: April 28, 2015
    Date of Patent: September 4, 2018
    Assignee: The United States of America as Represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 10056259
    Abstract: Use of a single alloy conductor to form simultaneous ohmic contacts (SOC) to n- and p-type 4H-SiC. The single alloy conductor also is an effective diffusion barrier against gold (AU) and oxygen (O2) at high temperatures (e.g., up to 800° C.). The innovation may also provide an effective interconnecting metallization in a multi-level metallization device scheme.
    Type: Grant
    Filed: October 2, 2017
    Date of Patent: August 21, 2018
    Assignee: The United States of America as Represented by the Admin of National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 9975765
    Abstract: A process for fabricating relatively thin SiC diaphragms may include fast Reactive Ion Etching (RIE) followed by Dopant Selective Reactive Ion Etching (DSRIE). The process may produce silicon carbide (SiC) diaphragms thinner than 10 microns. These thinner, more sensitive diaphragms may then be used to effectively resolve sub-psi pressures in jet engines, for example.
    Type: Grant
    Filed: December 16, 2016
    Date of Patent: May 22, 2018
    Assignee: The United States of America as Represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Publication number: 20170370692
    Abstract: A system and method for determining a change in a thickness and temperature of a surface of a material are disclosed herein. The system and the method are usable in a thermal protection system of a space vehicle, such as an aeroshell of a space vehicle. The system and method may incorporate micro electric sensors arranged in a ladder network and capacitor strip sensors. Corrosion or ablation causes a change in an electrical property of the sensors. An amount of or rate of the corrosion or the ablation and a temperature of the material is determined based on the change of the electrical property of the sensors.
    Type: Application
    Filed: August 22, 2017
    Publication date: December 28, 2017
    Inventor: Robert S. Okojie
  • Patent number: 9046426
    Abstract: A modular apparatus for attaching sensors and electronics is disclosed. The modular apparatus includes a square recess including a plurality of cavities and a reference cavity such that a pressure sensor can be connected to the modular apparatus. The modular apparatus also includes at least one voltage input hole and at least one voltage output hole operably connected to each of the plurality of cavities such that voltage can be applied to the pressure sensor and received from the pressure sensor.
    Type: Grant
    Filed: June 15, 2012
    Date of Patent: June 2, 2015
    Assignee: The United States of America as Represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Robert S Okojie
  • Patent number: 8373175
    Abstract: Simultaneous formation of electrical ohmic contacts to silicon carbide (SiC) semiconductor having donor and acceptor impurities (n- and p-type doping, respectively) is disclosed. The innovation provides for ohmic contacts formed on SiC layers having n- and p-doping at one process step during the fabrication of the semiconductor device. Further, the innovation provides a non-discriminatory, universal ohmic contact to both n- and p-type SiC, enhancing reliability of the specific contact resistivity when operated at temperatures in excess of 600° C.
    Type: Grant
    Filed: June 1, 2010
    Date of Patent: February 12, 2013
    Assignee: The United States of America as represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 7518234
    Abstract: Methods of bulk manufacturing high temperature sensor sub-assembly packages are disclosed and claimed. Sensors are sandwiched between a top cover and a bottom cover so as to enable the peripheries of the top covers, sensors and bottom covers to be sealed and bound securely together are disclosed and claimed. Sensors are placed on the bottom covers leaving the periphery of the bottom cover exposed. Likewise, top covers are placed on the sensors leaving the periphery of the sensor exposed. Individual sensor sub-assemblies are inserted into final packaging elements which are also disclosed and claimed. Methods of directly attaching wires or pins to contact pads on the sensors are disclosed and claimed. Sensors, such as pressure sensors and accelerometers, and headers made out of silicon carbide and aluminum nitride are disclosed and claimed. Reference cavities are formed in some embodiments disclosed and claimed herein where top covers are not employed.
    Type: Grant
    Filed: August 25, 2004
    Date of Patent: April 14, 2009
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Admistration
    Inventor: Robert S. Okojie
  • Patent number: 7438030
    Abstract: An actuator operated microvalve and the method of making same is disclosed and claimed. The microvalve comprises a SiC housing which includes a first lower portion and a second upper portion. The lower portion of the SiC housing includes a passageway therethrough, a microvalve seat, and a moveable SiC diaphragm. The SiC diaphragm includes a centrally located boss and radially extending corrugations which may be sinusoidally shaped. The boss of the SiC diaphragm moves and modulates in a range of positions between a closed position wherein the boss interengages said microvalve seat prohibiting communication of fluid through the passageway and a fully open position when the boss is spaced apart from the seat at its maximum permitting communication of fluid through said passageway. The actuator includes a SiC top plate affixed to the boss of the diaphragm and a first electrode and the second upper portion of the SiC housing further includes a second electrode.
    Type: Grant
    Filed: August 26, 2005
    Date of Patent: October 21, 2008
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 6845664
    Abstract: Methods of bulk manufacturing high temperature sensor sub-assembly packages are disclosed and claimed. Sensors are sandwiched between a top cover and a bottom cover so as to enable the peripheries of the top covers, sensors and bottom covers to be sealed and bound securely together are disclosed and claimed. Sensors are placed on the bottom covers leaving the periphery of the bottom cover exposed. Likewise, top covers are placed on the sensors leaving the periphery of the sensor exposed. Individual sensor sub-assemblies are inserted into final packaging elements which are also disclosed and claimed. Methods of directly attaching wires or pins to contact pads on the sensors are disclosed and claimed. Sensors, such as pressure sensors and accelerometers, and headers made out of silicon carbide and aluminum nitride are disclosed and claimed. Reference cavities are formed in some embodiments disclosed and claimed herein where top covers are not employed.
    Type: Grant
    Filed: October 3, 2002
    Date of Patent: January 25, 2005
    Assignee: The United States of America as represented by the Administrator of National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 6794213
    Abstract: A high temperature anemometer includes a pair of substrates. One of the substrates has a plurality of electrodes on a facing surface, while the other of the substrates has a sensor cavity on a facing surface. A sensor is received in the sensor cavity, wherein the sensor has a plurality of bondpads, and wherein the bond pads contact the plurality of electrodes when the facing surfaces are mated with one another. The anemometer further includes a plurality of plug-in pins, wherein the substrate with the cavity has a plurality of trenches with each one receiving a plurality of plug-in pins. The plurality of plug-in pins contact the plurality of electrodes when the substrates are mated with one another. The sensor cavity is at an end of one of the substrates such that the sensor partially extends from the substrate. The sensor and the substrates are preferably made of silicon carbide.
    Type: Grant
    Filed: August 5, 2003
    Date of Patent: September 21, 2004
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Robert S. Okojie, Gustave C. Fralick, George J. Saad
  • Patent number: 6770208
    Abstract: A nozzle body and assembly for delivering atomized fuel to a combustion chamber. The nozzle body is rotatably mounted onto a substrate. One or more curvilinear fuel delivery channels are in flow communication with an internal fuel distribution cavity formed in the nozzle body. Passage of pressurized fuel through the nozzle body causes the nozzle body to rotate. Components of the nozzle assembly are formed of silicon carbide having surfaces etched by deep reactive ion etching utilizing MEMS technology. A fuel premix chamber is carried on the substrate in flow communication with a supply passage in the nozzle body.
    Type: Grant
    Filed: August 13, 2002
    Date of Patent: August 3, 2004
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 6769303
    Abstract: A method of bulk manufacturing SiC sensors is disclosed and claimed. Materials other than SiC may be used as the substrate material. Sensors requiring that the SiC substrate be pierced are also disclosed and claimed. A process flow reversal is employed whereby the metallization is applied first before the recesses are etched into or through the wafer. Aluminum is deposited on the entire planar surface of the metallization. Photoresist is spun onto the substantially planar surface of the Aluminum which is subsequently masked (and developed and removed). Unwanted Aluminum is etched with aqueous TMAH and subsequently the metallization is dry etched. Photoresist is spun onto the still substantially planar surface of Aluminum and oxide and then masked (and developed and removed) leaving the unimidized photoresist behind. Next, ITO is applied over the still substantially planar surface of Aluminum, oxide and unimidized photoresist.
    Type: Grant
    Filed: September 24, 2003
    Date of Patent: August 3, 2004
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 6706549
    Abstract: A method of bulk manufacturing SiC sensors is disclosed and claimed. Materials other than SiC may be used as the substrate material. Sensors requiring that the SiC substrate be pierced are also disclosed and claimed. A process flow reversal is employed whereby the metallization is applied first before the recesses are etched into or through the wafer. Aluminum is deposited on the entire planar surface of the metallization. Photoresist is spun onto the substantially planar surface of the Aluminum which is subsequently masked (and developed and removed). Unwanted Aluminum is etched with aqueous TMAH and subsequently the metallization is dry etched. Photoresist is spun onto the still substantially planar surface of Aluminum and oxide and then masked (and developed and removed) leaving the unimidized photoresist behind. Next, ITO is applied over the still substantially planar surface of Aluminum, oxide and unimidized photoresist.
    Type: Grant
    Filed: April 12, 2002
    Date of Patent: March 16, 2004
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 6647809
    Abstract: A high temperature anemometer includes a pair of substrates. One of the substrates has a plurality of electrodes on a facing surface, while the other of the substrates has a sensor cavity on a facing surface. A sensor is received in the sensor cavity, wherein the sensor has a plurality of bondpads, and wherein the bond pads contact the plurality of electrodes when the facing surfaces are mated with one another. The anemometer further includes a plurality of plug-in pins, wherein the substrate with the cavity has a plurality of trenches with each one receiving a plurality of plug-in pins. The plurality of plug-in pins contact the plurality of electrodes when the substrates are mated with one another. The sensor cavity is at an end of one of the substrates such that the sensor partially extends from the substrate. The sensor and the substrates are preferably made of silicon carbide.
    Type: Grant
    Filed: August 29, 2002
    Date of Patent: November 18, 2003
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Robert S. Okojie, Gustave C. Fralick, George J. Saad
  • Patent number: 6513730
    Abstract: A nozzle body and assembly for delivering atomized fuel to a combustion chamber. The nozzle body is rotatably mounted onto a substrate. One or more curvilinear fuel delivery channels are in flow communication with an internal fuel distribution cavity formed in the nozzle body. Passage of pressurized fuel through the nozzle body causes the nozzle body to rotate. Components of the nozzle assembly are formed of silicon carbide having surfaces etched by deep reactive ion etching utilizing MEMS technology. A fuel premix chamber is carried on the substrate in flow communication with a supply passage in the nozzle body.
    Type: Grant
    Filed: March 21, 2001
    Date of Patent: February 4, 2003
    Assignee: The United States of America as represented by the National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 6426296
    Abstract: A method and apparatus for processing a wafer comprising a material selected from an electrical semiconducting material and an electrical insulating material. The wafer has opposed generally planar front and rear sides and a peripheral edge, wherein said wafer is pressed against a pad in the presence of a slurry to reduce its thickness. The thickness of the wafer is controlled by first forming a recess such as a dimple on the rear side of the wafer. A first electrical conducting strip extends from a first electrical connection means to the base surface of the recess to the second electrical connector. The first electrical conducting strip overlies the base surface of the recess. There is also a second electrical conductor with an electrical potential source between the first electrical connector and the second electrical connector to form.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: July 30, 2002
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Robert S. Okojie
  • Patent number: 6248646
    Abstract: A method of preparing small wafers for compatibility with conventional large wafer fabrication equipment comprising the following steps: indenting a face of a large wafer to form an array of depressions thereon, each depression sized to matingly accept a lower portion of a small wafer; applying a bonding medium to an exterior side of the depressions on the indented face of the large wafer; matingly fitting the small wafers into the depressions so that the small wafers are positioned in an array on the large wafer; and, removing the top portion of the small wafers standing out of the depressions by chemical mechanical polishing so that the remaining portions of the small wafers then have a uniform thickness generally equal to the depth of the indentations in the large wafer. A preferred aspect of this invention provides for a method as above wherein the small wafer is SiC and the large wafer is made from an amorphous substance which comprises SiC or aluminum nitride.
    Type: Grant
    Filed: June 11, 1999
    Date of Patent: June 19, 2001
    Inventor: Robert S. Okojie