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: 20240429122
    Abstract: A thermally conductive interposer includes an interposer substrate having a first substrate surface and a second substrate surface. The first substrate surface being configured to be attached to a first device component. The second substrate surface being configured to be attached to a second device component. The interposer substrate being configured to support the second device component on the first device component and integrate the first device component and the second device component within a microelectronic device. Further, the interposer substrate is configured to transfer heat between the first device component and the second device component; and the interposer substrate is configured to be electrically nonconductive.
    Type: Application
    Filed: June 23, 2023
    Publication date: December 26, 2024
    Inventors: Kyle BOTHE, James TWEEDIE, Fabian RADULESCU, Michael SCHUETTE, Jeremy FISHER, Basim NOORI, Scott SHEPPARD
  • Publication number: 20240429120
    Abstract: Semiconductor devices are provided. In one example, a semiconductor device includes a Group III-nitride semiconductor structure. The semiconductor device may include a gate contact on the Group III-nitride semiconductor structure. The semiconductor device may include a field plate overlapping the Group III-nitride semiconductor structure. The semiconductor device may include a thermally conductive passivation layer overlapping the gate contact. The thermally conductive passivation layer may be between the field plate and the Group III-nitride semiconductor structure. The thermally conductive passivation layer may contact the Group III-nitride semiconductor structure. The thermally conductive passivation layer may have a thermal conductivity of at least about 80 W/(m·k).
    Type: Application
    Filed: June 23, 2023
    Publication date: December 26, 2024
    Inventors: Michael Lee Schuette, KyoungKeun Joseph Lee, Matthew R. King, Christer Hallin, Fabian Radulescu, Thomas Albert Kuhr, Scott Sheppard, James Scott Tweedie, Kyle Bothe
  • Publication number: 20240266348
    Abstract: A transistor device includes a substrate and a plurality of transistor unit cells arranged in parallel on the substrate. Each of the transistor unit cells includes a source contact, a drain contact, and a gate finger between the source contact and the drain contact. The gate finger extends in a first direction and has a first end and a second end. The transistor device further includes a first solder bump on the transistor device that is within a periphery of the active region of the device and is electrically connected to the gate finger of a first one of the unit cells at a feed point that is between the first end and the second end of the gate finger.
    Type: Application
    Filed: February 3, 2023
    Publication date: August 8, 2024
    Inventors: Fabian Radulescu, Basim Noori, Scott Sheppard, Qianli Mu, Jeremy Fisher, Dan Namishia
  • Publication number: 20240162304
    Abstract: A transistor device may include a semiconductor structure including a channel layer and a barrier layer on the channel layer, wherein the barrier layer has a higher bandgap than the channel layer; a source contact and a drain contact on the barrier layer; a gate contact on the semiconductor structure between the source contact and the drain contact, the gate contact including a drain-side wing portion extending from a central portion of the gate contact; and a field plate on the semiconductor structure between the gate contact and the drain contact and laterally offset from the gate contact by a distance. The field plate may include a first wing portion extending from a central portion of the field plate.
    Type: Application
    Filed: January 9, 2024
    Publication date: May 16, 2024
    Inventors: Jeremy Fisher, Kyle Bothe, Terry Alcorn, Daniel Namishia, Jia Guo, Matthew King, Saptharishi Sriram, Fabian Radulescu, Scott Sheppard, Yueying Liu
  • Publication number: 20240063300
    Abstract: A high electron mobility transistor comprises a semiconductor layer structure that includes a channel layer and a barrier layer and source and drain contacts on the semiconductor layer structure. A gate contact and a multi-layer passivation structure are provided on the semiconductor layer structure between the source contact and the drain contact. The multi-layer passivation structure comprises at least first and second silicon nitride layers that have different material compositions. A spacer passivation layer is provided on sidewalls of the first and second silicon nitride layers. A material composition of the spacer passivation layer is different than a material composition of at least one of the layers of the multi-layer passivation structure.
    Type: Application
    Filed: August 18, 2022
    Publication date: February 22, 2024
    Inventors: Kyle Bothe, Chris Hardiman, Elizabeth Keenan, Jia Guo, Fabian Radulescu, Scott Sheppard
  • Patent number: 11887945
    Abstract: The present disclosure relates to a semiconductor device with isolation and/or protection structures. A semiconductor device can include a substrate, a first transistor and a second transistor, wherein the first transistor and the second transistor are formed on the substrate, and an isolation structure formed on the substrate. The isolation structure can be formed on the substrate between the first transistor and the second transistor. The isolation structure can be configured to isolate the first transistor and the second transistor.
    Type: Grant
    Filed: September 30, 2020
    Date of Patent: January 30, 2024
    Assignee: WOLFSPEED, INC.
    Inventors: Lei Zhao, Fabian Radulescu
  • Patent number: 11869964
    Abstract: A transistor device includes a semiconductor epitaxial layer structure including a channel layer and a barrier layer on the channel layer, wherein the barrier layer has a higher bandgap than the channel layer. A modified access region is provided at an upper surface of the barrier layer opposite the channel layer. The modified access region includes a material having a lower surface barrier height than the barrier layer. A source contact and a drain contact are formed on the barrier layer, and a gate contact is formed between source contact and the drain contact.
    Type: Grant
    Filed: May 20, 2021
    Date of Patent: January 9, 2024
    Assignee: Wolfspeed, Inc.
    Inventors: Kyoung-Keun Lee, Fabian Radulescu, Scott Sheppard
  • Patent number: 11842997
    Abstract: An integrated circuit device includes a radio frequency transistor amplifier die having a first surface, a second surface, a semiconductor layer structure that is between the first and second surfaces and includes a plurality of transistor cells adjacent the first surface, and terminals coupled to the transistor cells. At least one passive electronic component is provided on the second surface of the die and is electrically connected to at least one of the terminals, for example, by at least one conductive via. One or more conductive pillar structures may protrude from the first surface of the die to provide electrical connections to one or more of the terminals.
    Type: Grant
    Filed: March 21, 2022
    Date of Patent: December 12, 2023
    Assignee: Wolfspeed, Inc.
    Inventors: Terry Alcorn, Daniel Namishia, Fabian Radulescu
  • Publication number: 20230395670
    Abstract: A transistor device includes a semiconductor structure comprising a channel layer and a barrier layer; source and drain contacts on the semiconductor structure; and a gate on the semiconductor structure between the source and drain contacts. A first portion of the barrier layer extending between the source or drain contact and the gate has a first thickness, a second portion of the barrier layer between the gate and the channel layer has a second thickness, and the first thickness is about 1.5 times to 4 times greater than the second thickness. Related methods of fabrication using a looped recess process are also discussed.
    Type: Application
    Filed: June 7, 2022
    Publication date: December 7, 2023
    Inventors: Chris Hardiman, Kyoung-Keun Lee, Kyle Bothe, Fabian Radulescu
  • Patent number: 11769768
    Abstract: An integrated circuit device includes a radio frequency transistor amplifier die having a first surface, a second surface, a semiconductor layer structure that is between the first and second surfaces and includes a plurality of transistor cells adjacent the first surface, and terminals coupled to the transistor cells. At least one passive electronic component is provided on the second surface of the die and is electrically connected to at least one of the terminals, for example, by at least one conductive via. One or more conductive pillar structures may protrude from the first surface of the die to provide electrical connections to one or more of the terminals.
    Type: Grant
    Filed: June 1, 2020
    Date of Patent: September 26, 2023
    Assignee: Wolfspeed, Inc.
    Inventors: Terry Alcorn, Daniel Namishia, Fabian Radulescu
  • Patent number: 11735538
    Abstract: A semiconductor device configured for a radio frequency (RF) application and further configured for passive device integration and/or improved cooling includes a substrate; an active region portion arranged on the substrate, the active region portion includes at least one radio frequency (RF) transistor amplifier; a cavity arranged within the substrate; and one or more radio frequency (RF) devices arranged in the cavity.
    Type: Grant
    Filed: February 17, 2020
    Date of Patent: August 22, 2023
    Assignee: WOLFSPEED, INC.
    Inventor: Fabian Radulescu
  • Patent number: 11682634
    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: October 1, 2020
    Date of Patent: June 20, 2023
    Assignee: Wolfspeed, Inc.
    Inventors: Kyle Bothe, Dan Namishia, Fabian Radulescu, Scott Sheppard
  • Patent number: 11658234
    Abstract: A transistor device includes a semiconductor epitaxial layer structure including a channel layer and a barrier layer on the channel layer, a source contact and a drain contact on the barrier layer, an insulating layer on the semiconductor layer between the source contact and the drain contact, and a gate contact on the insulating layer. The gate contact includes a central portion that extends through the insulating layer and contacts the barrier layer and a drain side wing that extends laterally from the central portion of the gate toward the drain contact by a distance ?D. The drain side wing of the gate contact is spaced apart from the barrier layer by a distance d1 that is equal to a thickness of the insulating layer. The distance ?D is less than about 0.3 ?m, and the distance d1 is less than about 80 nm.
    Type: Grant
    Filed: May 20, 2021
    Date of Patent: May 23, 2023
    Assignee: Wolfspeed, Inc.
    Inventors: Kyle Bothe, Terry Alcorn, Dan Namishia, Jia Guo, Matt King, Saptharishi Sriram, Jeremy Fisher, Fabian Radulescu, Scott Sheppard, Yueying Liu
  • Patent number: 11646310
    Abstract: An integrated circuit device includes a radio frequency transistor amplifier die having a first surface, a second surface, a semiconductor layer structure that is between the first and second surfaces and includes a plurality of transistor cells adjacent the first surface, and terminals coupled to the transistor cells. At least one passive electronic component is provided on the second surface of the die and is electrically connected to at least one of the terminals, for example, by at least one conductive via. One or more conductive pillar structures may protrude from the first surface of the die to provide electrical connections to one or more of the terminals.
    Type: Grant
    Filed: June 1, 2020
    Date of Patent: May 9, 2023
    Assignee: Wolfspeed, Inc.
    Inventors: Terry Alcorn, Daniel Namishia, Fabian Radulescu
  • Patent number: 11621322
    Abstract: A transistor amplifier package includes a base, one or more transistor dies on the base, first and second leads coupled to the one or more transistor dies and defining respective radio frequency (RF) signal paths, and an isolation structure on the base between the respective RF signal paths. The isolation structure includes first and second wire bonds. The first and second wire bonds may have a crossed configuration defining at least one cross point therebetween. Related wire bond-based isolation structures are also discussed.
    Type: Grant
    Filed: July 30, 2020
    Date of Patent: April 4, 2023
    Assignee: Wolfspeed, Inc.
    Inventors: Lei Zhao, Fabian Radulescu
  • Patent number: 11616136
    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: February 19, 2021
    Date of Patent: March 28, 2023
    Assignee: Wolfspeed, Inc.
    Inventors: Kyle Bothe, Evan Jones, Dan Namishia, Chris Hardiman, Fabian Radulescu, Terry Alcorn, Scott Sheppard, Bruce Schmukler
  • Publication number: 20230075505
    Abstract: A radio frequency (“RF”) transistor amplifier die includes a semiconductor layer structure having a plurality of transistor cells, and an insulating layer on a surface of the semiconductor layer structure. Conductive pillar structures protrude from the insulating layer opposite the surface of the semiconductor layer structure, and are configured to provide input signal, output signal, or ground connections to the transistor cells. The ground connections are arranged between the input and/or output signal connections to the transistor cells. Related devices and packages are also discussed.
    Type: Application
    Filed: September 3, 2021
    Publication date: March 9, 2023
    Inventors: Fabian Radulescu, Basim Noori, Scott Sheppard, Kwangmo Chris Lim
  • Patent number: 11587842
    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: October 29, 2020
    Date of Patent: February 21, 2023
    Assignee: Wolfspeed, Inc.
    Inventors: Chris Hardiman, Kyoung-Keun Lee, Fabian Radulescu, Daniel Namishia, Scott Thomas Sheppard
  • Patent number: 11533025
    Abstract: The present disclosure relates to added isolation between transistors in a multiple path amplifier circuit. The multiple path amplifier circuit includes a substrate, a first transistor on the substrate in a first path, and a second transistor on the substrate in a second path. The multiple path amplifier circuit also includes at least one electrical connection associated with the first and the second transistors and positioned to at least partially extend between the first path and the second path.
    Type: Grant
    Filed: June 18, 2020
    Date of Patent: December 20, 2022
    Assignee: WOLFSPEED, INC.
    Inventors: Lei Zhao, Fabian Radulescu
  • Publication number: 20220384290
    Abstract: A semiconductor die includes a semiconductor body, and a multi-layer environmental barrier on the semiconductor body. The multi-layer environmental barrier includes a plurality of sublayers that are stacked on the semiconductor body. Each of the sublayers comprises a respective stress in one or more directions, where the respective stresses of at least two of the sublayers are different. The sublayers may include a first stressor sublayer comprising first stress, and a second stressor sublayer comprising a second stress that at least partially compensates for the first stress in the one or more directions. Related devices and methods of fabrication are also discussed.
    Type: Application
    Filed: February 3, 2022
    Publication date: December 1, 2022
    Inventors: Kyoung-Keun Lee, Daniel Etter, Fabian Radulescu, Scott Sheppard, Daniel Namishia