Patents by Inventor Fabian Radulescu

Fabian Radulescu 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: 20210111254
    Abstract: A transistor includes a semiconductor layer structure, a source electrode and a drain electrode on the semiconductor layer structure, a gate on a surface of the semiconductor layer structure between the source electrode and the drain electrode, and a field plate. The field plate includes a first portion adjacent the gate and a second portion adjacent the source or drain electrode. The second portion of the field plate is farther from the surface of the semiconductor layer structure than the first portion of the field plate, and is closer to the surface of the semiconductor layer structure than an extended portion of the gate. Related devices and fabrication methods are also discussed.
    Type: Application
    Filed: October 14, 2019
    Publication date: April 15, 2021
    Inventors: Evan Jones, Terry Alcorn, Jia Guo, Fabian Radulescu, Scott Sheppard
  • Patent number: 10971612
    Abstract: A power amplifier comprising a GaN-based high electron mobility transistor (HEMT) device, wherein a power added efficiency (PAE) of the power amplifier is greater than 32% at P1DB during operation of the power amplifier between 26.5 GHz and 30.5 GHz.
    Type: Grant
    Filed: August 29, 2019
    Date of Patent: April 6, 2021
    Assignee: Cree, Inc.
    Inventors: Kyle Bothe, Evan Jones, Dan Namishia, Chris Hardiman, Fabian Radulescu, Terry Alcorn, Scott Sheppard, Bruce Schmukler
  • Patent number: 10937873
    Abstract: A high electron mobility transistor includes a channel layer, a barrier layer on the channel layer, source and drain contacts on the barrier layer, a gate contact between the source and drain contacts, and a multi-layer passivation structure on the upper surface of the barrier layer between the source contact and the drain contact. The multi-layer passivation structure includes a first passivation layer that comprises a charge dissipation material directly contacts the upper surface of the barrier layer and a second passivation layer comprising a different material than the first passivation layer that also directly contacts the upper surface of the barrier layer. In some embodiments, at least one recess may be formed in the upper surface of the barrier layer and the second passivation layer may be formed within the recesses.
    Type: Grant
    Filed: January 3, 2019
    Date of Patent: March 2, 2021
    Assignee: Cree, Inc.
    Inventors: Kyoung-Keun Lee, Fabian Radulescu, Scott Sheppard
  • Patent number: 10923585
    Abstract: A high electron mobility transistor (HEMT) includes a substrate comprising a first surface and a second surface on opposing sides of the substrate, a channel layer on the first surface of the substrate opposite the substrate, a barrier layer on the channel layer, a source contact comprising a first ohmic contact on an upper surface of the barrier layer, and a via extending from the second surface of the substrate to the first ohmic contact.
    Type: Grant
    Filed: June 13, 2019
    Date of Patent: February 16, 2021
    Assignee: Cree, Inc.
    Inventors: Kyle Bothe, Evan Jones, Dan Namishia, Chris Hardiman, Fabian Radulescu, Jeremy Fisher, Scott Sheppard
  • Publication number: 20210043530
    Abstract: A semiconductor die includes a substrate, a first passivation layer over the substrate, and a second passivation layer over the first passivation layer and the substrate. The substrate has boundaries defined by a substrate termination edge. The first passivation layer is over the substrate such that it terminates at a first passivation termination edge that is inset from the substrate termination edge by a first distance. The second passivation layer is over the first passivation layer and the substrate such that it terminates at a second passivation termination edge that is inset from the substrate termination edge by a second distance. The second distance is less than the first distance such that the second passivation layer overlaps the first passivation layer.
    Type: Application
    Filed: October 29, 2020
    Publication date: February 11, 2021
    Inventors: Chris Hardiman, Kyoung-Keun Lee, Fabian Radulescu, Daniel Namishia, Scott Thomas Sheppard
  • Publication number: 20210028127
    Abstract: A packaged electronic circuit includes a substrate having an upper surface, a first metal layer on the upper surface of the substrate, a first polymer layer on the first metal layer opposite the substrate, a second metal layer on the first polymer layer opposite the first metal layer, a dielectric layer on the first polymer layer and at least a portion of the second metal layer and a second polymer layer on the dielectric layer.
    Type: Application
    Filed: October 1, 2020
    Publication date: January 28, 2021
    Inventors: Kyle Bothe, Dan Namishia, Fabian Radulescu, Scott Sheppard
  • Patent number: 10886189
    Abstract: A semiconductor die includes a substrate, a first passivation layer over the substrate, and a second passivation layer over the first passivation layer and the substrate. The substrate has boundaries defined by a substrate termination edge. The first passivation layer is over the substrate such that it terminates at a first passivation termination edge that is inset from the substrate termination edge by a first distance. The second passivation layer is over the first passivation layer and the substrate such that it terminates at a second passivation termination edge that is inset from the substrate termination edge by a second distance. The second distance is less than the first distance such that the second passivation layer overlaps the first passivation layer.
    Type: Grant
    Filed: May 1, 2019
    Date of Patent: January 5, 2021
    Assignee: Cree, Inc.
    Inventors: Chris Hardiman, Kyoung-Keun Lee, Fabian Radulescu, Daniel Namishia, Scott Thomas Sheppard
  • Publication number: 20200395475
    Abstract: A power amplifier comprising a GaN-based high electron mobility transistor (HEMT) device, wherein a power added efficiency (PAE) of the power amplifier is greater than 32% at P1 DB during operation of the power amplifier between 26.5 GHz and 30.5 GHz.
    Type: Application
    Filed: August 29, 2019
    Publication date: December 17, 2020
    Inventors: Kyle Bothe, Evan Jones, Dan Namishia, Chris Hardiman, Fabian Radulescu, Terry Alcorn, Scott Sheppard, Bruce Schmukler
  • Publication number: 20200395474
    Abstract: A high electron mobility transistor (HEMT) includes a substrate comprising a first surface and a second surface on opposing sides of the substrate, a channel layer on the first surface of the substrate opposite the substrate, a barrier layer on the channel layer, a source contact comprising a first ohmic contact on an upper surface of the barrier layer, and a via extending from the second surface of the substrate to the first ohmic contact.
    Type: Application
    Filed: June 13, 2019
    Publication date: December 17, 2020
    Inventors: Kyle Bothe, Evan Jones, Dan Namishia, Chris Hardiman, Fabian Radulescu, Jeremy Fisher, Scott Sheppard
  • Patent number: 10840162
    Abstract: A semiconductor die includes a substrate, a first passivation layer over the substrate, and a second passivation layer over the first passivation layer and the substrate. The substrate has boundaries defined by a substrate termination edge. The first passivation layer is over the substrate such that it terminates at a first passivation termination edge that is inset from the substrate termination edge by a first distance. The second passivation layer is over the first passivation layer and the substrate such that it terminates at a second passivation termination edge that is inset from the substrate termination edge by a second distance. The second distance is less than the first distance such that the second passivation layer overlaps the first passivation layer.
    Type: Grant
    Filed: May 1, 2019
    Date of Patent: November 17, 2020
    Assignee: Cree, Inc.
    Inventors: Chris Hardiman, Kyoung-Keun Lee, Fabian Radulescu, Daniel Namishia, Scott Thomas Sheppard
  • Patent number: 10811370
    Abstract: A packaged electronic circuit includes a substrate having an upper surface, a first metal layer on the upper surface of the substrate, a first polymer layer on the first metal layer opposite the substrate, a second metal layer on the first polymer layer opposite the first metal layer, a dielectric layer on the first polymer layer and at least a portion of the second metal layer and a second polymer layer on the dielectric layer.
    Type: Grant
    Filed: April 24, 2018
    Date of Patent: October 20, 2020
    Assignee: Cree, Inc.
    Inventors: Kyle Bothe, Dan Namishia, Fabian Radulescu, Scott Sheppard
  • Publication number: 20200219987
    Abstract: A high electron mobility transistor includes a channel layer, a barrier layer on the channel layer, source and drain contacts on the barrier layer, a gate contact between the source and drain contacts, and a multi-layer passivation structure on the upper surface of the barrier layer between the source contact and the drain contact. The multi-layer passivation structure includes a first passivation layer that comprises a charge dissipation material directly contacts the upper surface of the barrier layer and a second passivation layer comprising a different material than the first passivation layer that also directly contacts the upper surface of the barrier layer. In some embodiments, at least one recess may be formed in the upper surface of the barrier layer and the second passivation layer may be formed within the recesses.
    Type: Application
    Filed: January 3, 2019
    Publication date: July 9, 2020
    Inventors: Kyoung-Keun Lee, Fabian Radulescu, Scott Sheppard
  • Publication number: 20190326230
    Abstract: A packaged electronic circuit includes a substrate having an upper surface, a first metal layer on the upper surface of the substrate, a first polymer layer on the first metal layer opposite the substrate, a second metal layer on the first polymer layer opposite the first metal layer, a dielectric layer on the first polymer layer and at least a portion of the second metal layer and a second polymer layer on the dielectric layer.
    Type: Application
    Filed: April 24, 2018
    Publication date: October 24, 2019
    Inventors: Kyle Bothe, Dan Namishia, Fabian Radulescu, Scott Sheppard
  • Publication number: 20190259682
    Abstract: A semiconductor die includes a substrate, a first passivation layer over the substrate, and a second passivation layer over the first passivation layer and the substrate. The substrate has boundaries defined by a substrate termination edge. The first passivation layer is over the substrate such that it terminates at a first passivation termination edge that is inset from the substrate termination edge by a first distance. The second passivation layer is over the first passivation layer and the substrate such that it terminates at a second passivation termination edge that is inset from the substrate termination edge by a second distance. The second distance is less than the first distance such that the second passivation layer overlaps the first passivation layer.
    Type: Application
    Filed: May 1, 2019
    Publication date: August 22, 2019
    Inventors: Chris Hardiman, Kyoung-Keun Lee, Fabian Radulescu, Daniel Namishia, Scott Thomas Sheppard
  • Patent number: 10332817
    Abstract: A semiconductor die includes a substrate, a first passivation layer over the substrate, and a second passivation layer over the first passivation layer and the substrate. The substrate has boundaries defined by a substrate termination edge. The first passivation layer is over the substrate such that it terminates at a first passivation termination edge that is inset from the substrate termination edge by a first distance. The second passivation layer is over the first passivation layer and the substrate such that it terminates at a second passivation termination edge that is inset from the substrate termination edge by a second distance. The second distance is less than the first distance such that the second passivation layer overlaps the first passivation layer.
    Type: Grant
    Filed: December 1, 2017
    Date of Patent: June 25, 2019
    Assignee: Cree, Inc.
    Inventors: Chris Hardiman, Kyoung-Keun Lee, Fabian Radulescu, Daniel Namishia, Scott Thomas Sheppard
  • Publication number: 20190172769
    Abstract: A semiconductor die includes a substrate, a first passivation layer over the substrate, and a second passivation layer over the first passivation layer and the substrate. The substrate has boundaries defined by a substrate termination edge. The first passivation layer is over the substrate such that it terminates at a first passivation termination edge that is inset from the substrate termination edge by a first distance. The second passivation layer is over the first passivation layer and the substrate such that it terminates at a second passivation termination edge that is inset from the substrate termination edge by a second distance. The second distance is less than the first distance such that the second passivation layer overlaps the first passivation layer.
    Type: Application
    Filed: December 1, 2017
    Publication date: June 6, 2019
    Inventors: Chris Hardiman, Kyoung-Keun Lee, Fabian Radulescu, Daniel Namishia, Scott Thomas Sheppard
  • Patent number: 9847411
    Abstract: A transistor device including a field plate is described. One embodiment of such a device includes a field plate separated from a semiconductor layer by a thin spacer layer. In one embodiment, the thickness of spacer layer separating the field plate from the semiconductor layers is less than the thickness of spacer layer separating the field plate from the gate. In another embodiment, the non-zero distance separating the field plate from the semiconductor layers is about 1500 ? or less. Devices according to the present invention can show capacitances which are less drain bias dependent, resulting in improved linearity.
    Type: Grant
    Filed: June 27, 2013
    Date of Patent: December 19, 2017
    Assignee: CREE, INC.
    Inventors: Saptharishi Sriram, Terry Alcorn, Fabian Radulescu, Scott Sheppard
  • Patent number: 9679981
    Abstract: A multi-stage transistor device is described. One embodiment of such a device is a dual-gate transistor, where the second stage gate is separated from a barrier layer by a thin spacer layer and is grounded through a connection to the source. In one embodiment the thin spacer layer and the second stage gate are placed in an aperture in a spacer layer. In another embodiment, the second stage gate is separated from a barrier layer by a spacer layer. The device can exhibit improved linearity and reduced complexity and cost.
    Type: Grant
    Filed: June 9, 2013
    Date of Patent: June 13, 2017
    Assignee: CREE, INC.
    Inventors: Saptharishi Sriram, Terry Alcorn, Fabian Radulescu, Scott Sheppard
  • Patent number: 9608078
    Abstract: A transistor device includes a semiconductor body, a spacer layer, and a field plate. The spacer layer is over at least a portion of a surface of the semiconductor body. The field plate is over at least a portion of the spacer layer, and includes a first current carrying layer, a refractory metal interposer layer over the first current carrying layer, and a second current carrying layer over the refractory metal interposer layer. By including the refractory metal interposer layer between the first current carrying layer and the second current carrying layer, the electromigration of metals in the field plate is significantly reduced. Since electromigration of metals in the field plate is a common cause of transistor device failures, reducing the electromigration of metals in the field plate improves the reliability and lifetime of the transistor device.
    Type: Grant
    Filed: October 17, 2014
    Date of Patent: March 28, 2017
    Assignee: Cree, Inc.
    Inventors: Helmut Hagleitner, Fabian Radulescu, Saptharishi Sriram, Daniel Etter
  • Patent number: 9536783
    Abstract: Embodiments of a semiconductor wafer having wafer-level die attach metallization on a back-side of the semiconductor wafer, resulting semiconductor dies, and methods of manufacturing the same are disclosed. In one embodiment, a semiconductor wafer includes a semiconductor structure and a front-side metallization that includes front-side metallization elements for a number of semiconductor die areas. The semiconductor wafer also includes vias that extend from a back-side of the semiconductor structure to the front-side metallization elements. A back-side metallization is on the back-side of the semiconductor structure and within the vias. For each via, one or more barrier layers are on a portion of the back-side metallization that is within the via and around a periphery of the via. The semiconductor wafer further includes wafer-level die attach metallization on the back-side metallization other than the portions of the back-side metallization that are within the vias and around the peripheries of the vias.
    Type: Grant
    Filed: January 7, 2015
    Date of Patent: January 3, 2017
    Assignee: Cree, Inc.
    Inventors: Fabian Radulescu, Helmut Hagleitner, Terry Alcorn, William T. Pulz, Van Mieczkowski