Patents by Inventor Umesh Mishra

Umesh Mishra 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).

  • Publication number: 20110193619
    Abstract: An electronic component includes a high-voltage depletion-mode transistor and a low-voltage enhancement-mode transistor both encased in a single package. A source electrode of the high-voltage depletion-mode transistor is electrically connected to a drain electrode of the low-voltage enhancement-mode transistor, a drain electrode of the high-voltage depletion-mode transistor is electrically connected to a drain lead of the single package, a gate electrode of the low-voltage enhancement-mode transistor is electrically connected to a gate lead of the single package, a gate electrode of the high-voltage depletion-mode transistor is electrically connected to an additional lead of the single package, and a source electrode of the low-voltage enhancement-mode transistor is electrically connected to a conductive structural portion of the single package.
    Type: Application
    Filed: February 5, 2010
    Publication date: August 11, 2011
    Applicant: Transphorm Inc.
    Inventors: Primit Parikh, James Honea, Carl C. Blake, JR., Robert Coffie, Yifeng Wu, Umesh Mishra
  • Patent number: 7994512
    Abstract: New Group III based diodes are disclosed having a low on state voltage (Vf) and structures to keep reverse current (Irev) relatively low. One embodiment of the invention is Schottky barrier diode made from the GaN material system in which the Fermi level (or surface potential) of is not pinned. The barrier potential at the metal-to-semiconductor junction varies depending on the type of metal used and using particular metals lowers the diode's Schottky barrier potential and results in a Vf in the range of 0.1-0.3V. In another embodiment a trench structure is formed on the Schottky diodes semiconductor material to reduce reverse leakage current. and comprises a number of parallel, equally spaced trenches with mesa regions between adjacent trenches. A third embodiment of the invention provides a GaN tunnel diode with a low Vf resulting from the tunneling of electrons through the barrier potential, instead of over it. This embodiment can also have a trench structure to reduce reverse leakage current.
    Type: Grant
    Filed: June 30, 2005
    Date of Patent: August 9, 2011
    Assignee: Cree, Inc.
    Inventors: Primit Parikh, Umesh Mishra
  • Publication number: 20110169054
    Abstract: A HEMT comprising a plurality of active semiconductor layers formed on a substrate. Source electrode, drain electrode, and gate are formed in electrical contact with the plurality of active layers. A spacer layer is formed on at least a portion of a surface of said plurality of active layers and covering the gate. A field plate is formed on the spacer layer and electrically connected to the source electrode, wherein the field plate reduces the peak operating electric field in the HEMT.
    Type: Application
    Filed: March 25, 2011
    Publication date: July 14, 2011
    Inventors: Yifeng Wu, Primit Parikh, Umesh Mishra, Marcia Moore
  • Publication number: 20110140172
    Abstract: Group III-nitride devices are described that include a stack of III-nitride layers, passivation layers, and conductive contacts. The stack includes a channel layer with a 2DEG channel, a barrier layer and a spacer layer. One passivation layer directly contacts a surface of the spacer layer on a side opposite to the channel layer and is an electrical insulator. The stack of III-nitride layers and the first passivation layer form a structure with a reverse side proximate to the first passivation layer and an obverse side proximate to the barrier layer. Another passivation layer is on the obverse side of the structure. Defected nucleation and stress management layers that form a buffer layer during the formation process can be partially or entirely removed.
    Type: Application
    Filed: December 10, 2009
    Publication date: June 16, 2011
    Applicant: TRANSPHORM INC.
    Inventors: Rongming Chu, Umesh Mishra, Rakesh K. Lal
  • Publication number: 20110127541
    Abstract: Planar Schottky diodes for which the semiconductor material includes a heterojunction which induces a 2DEG in at least one of the semiconductor layers. A metal anode contact is on top of the upper semiconductor layer and forms a Schottky contact with that layer. A metal cathode contact is connected to the 2DEG, forming an ohmic contact with the layer containing the 2DEG.
    Type: Application
    Filed: January 18, 2011
    Publication date: June 2, 2011
    Applicant: TRANSPHORM INC.
    Inventors: Yifeng Wu, Umesh Mishra, Primit Parikh, Rongming Chu, Ilan Ben-Yaacov, Likun Shen
  • Publication number: 20110121314
    Abstract: Enhancement mode III-nitride devices are described. The 2DEG is depleted in the gate region so that the device is unable to conduct current when no bias is applied at the gate. Both gallium face and nitride face devices formed as enhancement mode devices.
    Type: Application
    Filed: February 1, 2011
    Publication date: May 26, 2011
    Applicant: Transphorm Inc.
    Inventors: Chang Soo Suh, Umesh Mishra
  • Publication number: 20110114997
    Abstract: A multiple field plate transistor includes an active region, with a source, a drain, and a gate. A first spacer layer is over the active region between the source and the gate and a second spacer layer over the active region between the drain and the gate. A first field plate on the first spacer layer is connected to the gate. A second field plate on the second spacer layer is connected to the gate. A third spacer layer is on the first spacer layer, the second spacer layer, the first field plate, the gate, and the second field plate, with a third field plate on the third spacer layer and connected to the source. The transistor exhibits a blocking voltage of at least 600 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 5.0 m?-cm2, of at least 600 Volts while supporting a current of at least 3 Amps with an on resistance of no more than 5.3 m?-cm2, of at least 900 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 6.
    Type: Application
    Filed: January 26, 2011
    Publication date: May 19, 2011
    Inventors: YIFENG WU, Primit Parikh, Umesh Mishra
  • Patent number: 7915643
    Abstract: Enhancement mode III-nitride devices are described. The 2DEG is depleted in the gate region so that the device is unable to conduct current when no bias is applied at the gate. Both gallium face and nitride face devices formed as enhancement mode devices.
    Type: Grant
    Filed: September 17, 2007
    Date of Patent: March 29, 2011
    Assignee: Transphorm Inc.
    Inventors: Chang Soo Suh, Umesh Mishra
  • Patent number: 7915644
    Abstract: A HEMT comprising an active region comprising a plurality of active semiconductor layers formed on a substrate. Source electrode, drain electrode, and gate are formed in electrical contact with the active region. A spacer layer is formed on at least a portion of a surface of said active region and covering the gate. A field plate is formed on the spacer layer and electrically connected to the source electrode, wherein the field plate reduces the peak operating electric field in the HEMT.
    Type: Grant
    Filed: May 7, 2009
    Date of Patent: March 29, 2011
    Assignee: Cree, Inc.
    Inventors: Yifeng Wu, Primit Parikh, Umesh Mishra, Marcia Moore
  • Publication number: 20110062579
    Abstract: A circuit substrate has one or more active components and a plurality of passive circuit elements on a first surface. An active semiconductor device has a substrate with layers of material and a plurality of terminals. The active semiconductor device is flip-chip mounted on the circuit substrate and at least one of the terminals of the device is electrically connected to an active component on the circuit substrate. The active components on the substrate and the flip-chip mounted active semiconductor device, in combination with passive circuit elements, form preamplifiers and an output amplifier respectively. In a power switching configuration, the circuit substrate has logic control circuits on a first surface. A semiconductor transistor flip-chip mounted on the circuit substrate is electrically connected to the control circuits on the first surface to thereby control the on and off switching of the flip-chip mounted device.
    Type: Application
    Filed: November 22, 2010
    Publication date: March 17, 2011
    Inventors: UMESH MISHRA, Primit Parikh, Yifeng Wu
  • Patent number: 7898004
    Abstract: Planar Schottky diodes for which the semiconductor material includes a heterojunction which induces a 2DEG in at least one of the semiconductor layers. A metal anode contact is on top of the upper semiconductor layer and forms a Schottky contact with that layer. A metal cathode contact is connected to the 2DEG, forming an ohmic contact with the layer containing the 2DEG.
    Type: Grant
    Filed: December 10, 2008
    Date of Patent: March 1, 2011
    Assignee: Transphorm Inc.
    Inventors: Yifeng Wu, Umesh Mishra, Primit Parikh, Rongming Chu, Ilan Ben-Yaacov, Likun Shen
  • Patent number: 7893500
    Abstract: A multiple field plate transistor includes an active region, with a source, a drain, and a gate. A first spacer layer is over the active region between the source and the gate and a second spacer layer over the active region between the drain and the gate. A first field plate on the first spacer layer is connected to the gate. A second field plate on the second spacer layer is connected to the gate. A third spacer layer is on the first spacer layer, the second spacer layer, the first field plate, the gate, and the second field plate, with a third field plate on the third spacer layer and connected to the source. The transistor exhibits a blocking voltage of at least 600 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 5.0 m?-cm2, of at least 600 Volts while supporting a current of at least 3 Amps with an on resistance of no more than 5.3 m?-cm2, of at least 900 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 6.
    Type: Grant
    Filed: December 11, 2009
    Date of Patent: February 22, 2011
    Assignee: Cree, Inc.
    Inventors: Yifeng Wu, Primit Parikh, Umesh Mishra
  • Patent number: 7851825
    Abstract: Enhancement-mode III-nitride transistors are described that have a large source to drain barrier in the off state, low off state leakage, and low channel resistance in the access regions are described. The devices can include a charge depleting layer under the gate and/or a charge enhancing layer outside of the gate region, that is, in the access region.
    Type: Grant
    Filed: November 26, 2008
    Date of Patent: December 14, 2010
    Assignee: Transphorm Inc.
    Inventors: Chang Soo Suh, Ilan Ben-Yaacov, Robert Coffie, Umesh Mishra
  • Patent number: 7851909
    Abstract: A circuit substrate has one or more active components and a plurality of passive circuit elements on a first surface. An active semiconductor device has a substrate with layers of material and a plurality of terminals. The active semiconductor device is flip-chip mounted on the circuit substrate and at least one of the terminals of the device is electrically connected to an active component on the circuit substrate. The active components on the substrate and the flip-chip mounted active semiconductor device, in combination with passive circuit elements, form preamplifiers and an output amplifier respectively. In a power switching configuration, the circuit substrate has logic control circuits on a first surface. A semiconductor transistor flip-chip mounted on the circuit substrate is electrically connected to the control circuits on the first surface to thereby control the on and off switching of the flip-chip mounted device.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: December 14, 2010
    Assignee: Cree, Inc.
    Inventors: Umesh Mishra, Primit Parikh, Yifeng Wu
  • Publication number: 20100289067
    Abstract: A III-N device is described has a buffer layer, a first III-N material layer on the buffer layer, a second III-N material layer on the first III-N material layer on an opposite side from the buffer layer and a dispersion blocking layer between the buffer layer and the channel layer. The first III-N material layer is a channel layer and a compositional difference between the first III-N material layer and the second III-N material layer induces a 2DEG channel in the first III-N material layer. A sheet or a distribution of negative charge at an interface of the channel layer and the dispersion blocking layer confines electrons away from the buffer layer.
    Type: Application
    Filed: May 14, 2009
    Publication date: November 18, 2010
    Applicant: TRANSPHORM INC.
    Inventors: Umesh Mishra, Lee McCarthy, Nicholas Fichtenbaum
  • Publication number: 20100140660
    Abstract: Planar Schottky diodes for which the semiconductor material includes a heterojunction which induces a 2DEG in at least one of the semiconductor layers. A metal anode contact is on top of the upper semiconductor layer and forms a Schottky contact with that layer. A metal cathode contact is connected to the 2DEG, forming an ohmic contact with the layer containing the 2DEG.
    Type: Application
    Filed: December 10, 2008
    Publication date: June 10, 2010
    Inventors: Yifeng Wu, Umesh Mishra, Primit Parikh, Rongming Chu, Ilan Ben-Yaacov, Likun Shen
  • Publication number: 20100109051
    Abstract: A multiple field plate transistor includes an active region, with a source, a drain, and a gate. A first spacer layer is over the active region between the source and the gate and a second spacer layer over the active region between the drain and the gate. A first field plate on the first spacer layer is connected to the gate. A second field plate on the second spacer layer is connected to the gate. A third spacer layer is on the first spacer layer, the second spacer layer, the first field plate, the gate, and the second field plate, with a third field plate on the third spacer layer and connected to the source. The transistor exhibits a blocking voltage of at least 600 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 5.0 m?-cm2, of at least 600 Volts while supporting a current of at least 3 Amps with an on resistance of no more than 5.3 m?-cm2, of at least 900 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 6.
    Type: Application
    Filed: December 11, 2009
    Publication date: May 6, 2010
    Inventors: YIFENG WU, Primit Parikh, Umesh Mishra
  • Patent number: 7692263
    Abstract: A multiple field plate transistor includes an active region, with a source, a drain, and a gate. A first spacer layer is over the active region between the source and the gate and a second spacer layer over the active region between the drain and the gate. A first field plate on the first spacer layer is connected to the gate. A second field plate on the second spacer layer is connected to the gate. A third spacer layer is on the first spacer layer, the second spacer layer, the first field plate, the gate, and the second field plate, with a third field plate on the third spacer layer and connected to the source. The transistor exhibits a blocking voltage of at least 600 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 5.0 m?-cm2, of at least 600 Volts while supporting a current of at least 3 Amps with an on resistance of no more than 5.3 m?-cm2, of at least 900 Volts while supporting a current of at least 2 Amps with an on resistance of no more than 6.
    Type: Grant
    Filed: November 21, 2006
    Date of Patent: April 6, 2010
    Assignee: Cree, Inc.
    Inventors: Yifeng Wu, Primit Parikh, Umesh Mishra
  • Publication number: 20090315078
    Abstract: AlGaN/GaN HEMTs are disclosed having a thin AlGaN layer to reduce trapping and also having additional layers to reduce gate leakage and increase the maximum drive current. One HEMT according to the present invention comprises a high resistivity semiconductor layer with a barrier semiconductor layer on it. The barrier layer has a wider bandgap than the high resistivity layer and a 2DEG forms between the layers. Source and drain contacts contact the barrier layer, with part of the surface of the barrier layer uncovered by the contacts. An insulating layer is included on the uncovered surface of the barrier layer and a gate contact is included on the insulating layer. The insulating layer forms a barrier to gate leakage current and also helps to increase the HEMT's maximum current drive. The invention also includes methods for fabricating HEMTs according to the present invention. In one method, the HEMT and its insulating layer are fabricated using metal-organic chemical vapor deposition (MOCVD).
    Type: Application
    Filed: September 4, 2009
    Publication date: December 24, 2009
    Inventors: Primit Parikh, Umesh Mishra, Yifeng Wu
  • Publication number: 20090267116
    Abstract: A transistor comprising a plurality of active semiconductor layers on a substrate, with source and drain electrodes in contact with the semiconductor layers. A gate is formed between the source and drain electrodes and on the plurality of semiconductor layers. A plurality of field plates are arranged over the semiconductor layers, each of which extends from the edge of the gate toward the drain electrode, and each of which is isolated from said semiconductor layers and from the others of the field plates. The topmost of the field plates is electrically connected to the source electrode and the others of the field plates are electrically connected to the gate or the source electrode.
    Type: Application
    Filed: July 2, 2009
    Publication date: October 29, 2009
    Inventors: Yifeng Wu, Primit PARIKH, Umesh MISHRA, Marcia MOORE