Patents by Inventor Shailaja P. Rao

Shailaja P. Rao 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).

  • Thermal control for formation and processing of aluminum nitride
    Patent number: 11913136
    Abstract: In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.
    Type: Grant
    Filed: January 5, 2023
    Date of Patent: February 27, 2024
    Assignee: CRYSTAL IS, INC.
    Inventors: Robert T. Bondokov, Jianfeng Chen, Keisuke Yamaoka, Shichao Wang, Shailaja P. Rao, Takashi Suzuki, Leo J. Schowalter
  • Large, UV-transparent aluminum nitride single crystals
    Patent number: 11828002
    Abstract: In various embodiments, single-crystal aluminum nitride boules and substrates having high transparency to ultraviolet light and low defect density are formed. The single-crystal aluminum nitride may function as a platform for the fabrication of light-emitting devices such as light-emitting diodes and lasers.
    Type: Grant
    Filed: February 22, 2021
    Date of Patent: November 28, 2023
    Assignee: Crystal IS, Inc.
    Inventors: Robert T. Bondokov, Jianfeng Chen, Keisuke Yamaoka, Shichao Wang, Shailaja P. Rao, Takashi Suzuki, Leo J. Schowalter
  • THERMAL CONTROL FOR FORMATION AND PROCESSING OF ALUMINUM NITRIDE
    Publication number: 20230167584
    Abstract: In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.
    Type: Application
    Filed: January 5, 2023
    Publication date: June 1, 2023
    Inventors: Robert T. BONDOKOV, Jianfeng CHEN, Keisuke YAMAOKA, Shichao WANG, Shailaja P. RAO, Takashi SUZUKI, Leo J. SCHOWALTER
  • Thermal control for formation and processing of aluminum nitride
    Patent number: 11578425
    Abstract: In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.
    Type: Grant
    Filed: October 28, 2020
    Date of Patent: February 14, 2023
    Assignee: Crystal IS, Inc.
    Inventors: Robert T. Bondokov, Jianfeng Chen, Keisuke Yamaoka, Shichao Wang, Shailaja P. Rao, Takashi Suzuki, Leo J. Schowalter
  • LARGE, UV-TRANSPARENT ALUMINUM NITRIDE SINGLE CRYSTALS
    Publication number: 20210254240
    Abstract: In various embodiments, single-crystal aluminum nitride boules and substrates having high transparency to ultraviolet light and low defect density are formed. The single-crystal aluminum nitride may function as a platform for the fabrication of light-emitting devices such as light-emitting diodes and lasers.
    Type: Application
    Filed: February 22, 2021
    Publication date: August 19, 2021
    Inventors: Robert T. BONDOKOV, Jianfeng CHEN, Keisuke YAMAOKA, Shichao WANG, Shailaja P. RAO, Takashi SUZUKI, Leo J. SCHOWALTER
  • Defect reduction in seeded aluminum nitride crystal growth
    Patent number: 11015263
    Abstract: Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density?100 cm?2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.
    Type: Grant
    Filed: July 9, 2019
    Date of Patent: May 25, 2021
    Assignee: CRYSTAL IS, INC.
    Inventors: Robert T. Bondokov, Leo J. Schowalter, Kenneth Morgan, Glen A. Slack, Shailaja P. Rao, Shawn Robert Gibb
  • THERMAL CONTROL FOR FORMATION AND PROCESSING OF ALUMINUM NITRIDE
    Publication number: 20210108336
    Abstract: In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.
    Type: Application
    Filed: October 28, 2020
    Publication date: April 15, 2021
    Inventors: Robert T. BONDOKOV, Jianfeng CHEN, Keisuke YAMAOKA, Shichao WANG, Shailaja P. RAO, Takashi SUZUKI, Leo J. SCHOWALTER
  • UV-transparent aluminum nitride single crystal having a diameter of 35 mm to 150 mm and a predefined UV transparency metric at a wavelength of 265 nm
    Patent number: 10954608
    Abstract: In various embodiments, single-crystal aluminum nitride boules and substrates having high transparency to ultraviolet light and low defect density are formed. The single-crystal aluminum nitride may function as a platform for the fabrication of light-emitting devices such as light-emitting diodes and lasers.
    Type: Grant
    Filed: November 9, 2018
    Date of Patent: March 23, 2021
    Assignee: CRYSTAL IS, INC.
    Inventors: Robert T. Bondokov, Jianfeng Chen, Keisuke Yamaoka, Shichao Wang, Shailaja P. Rao, Takashi Suzuki, Leo J. Schowalter
  • Thermal control for formation and processing of aluminum nitride
    Patent number: 10851474
    Abstract: In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.
    Type: Grant
    Filed: December 16, 2019
    Date of Patent: December 1, 2020
    Assignee: CRYSTAL IS, INC.
    Inventors: Robert T. Bondokov, Jianfeng Chen, Keisuke Yamaoka, Shichao Wang, Shailaja P. Rao, Takashi Suzuki, Leo J. Schowalter
  • Aluminum nitride bulk crystals having high transparency to ultraviolet light and methods of forming them
    Patent number: 10801127
    Abstract: In various embodiments, methods of forming single-crystal AlN include providing a substantially undoped polycrystalline AlN ceramic having an oxygen concentration less than approximately 100 ppm, forming a single-crystal bulk AlN crystal by a sublimation-recondensation process at a temperature greater than approximately 2000° C., and cooling the bulk AlN crystal to a first temperature between approximately 1500° C. and approximately 1800° C. at a first rate less than approximately 250° C./hour.
    Type: Grant
    Filed: April 26, 2019
    Date of Patent: October 13, 2020
    Assignee: CRYSTAL IS, INC.
    Inventors: Sandra B. Schujman, Shailaja P. Rao, Robert T. Bondokov, Kenneth E. Morgan, Glen A. Slack, Leo J. Schowalter
  • THERMAL CONTROL FOR FORMATION AND PROCESSING OF ALUMINUM NITRIDE
    Publication number: 20200190694
    Abstract: In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.
    Type: Application
    Filed: December 16, 2019
    Publication date: June 18, 2020
    Inventors: Robert T. BONDOKOV, Jianfeng CHEN, Keisuke YAMAOKA, Shichao WANG, Shailaja P. RAO, Takashi SUZUKI, Leo J. SCHOWALTER
  • Thermal control for formation and processing of aluminum nitride
    Patent number: 10550493
    Abstract: In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.
    Type: Grant
    Filed: November 9, 2018
    Date of Patent: February 4, 2020
    Assignee: CRYSTAL IS, INC.
    Inventors: Robert T. Bondokov, Jianfeng Chen, Keisuke Yamaoka, Shichao Wang, Shailaja P. Rao, Takashi Suzuki, Leo J. Schowalter
  • DEFECT REDUCTION IN SEEDED ALUMINUM NITRIDE CRYSTAL GROWTH
    Publication number: 20200002841
    Abstract: Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density?100 cm?2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.
    Type: Application
    Filed: July 9, 2019
    Publication date: January 2, 2020
    Inventors: Robert T. Bondokov, Leo J. Schowalter, Kenneth Morgan, Glen A. Slack, Shailaja P. Rao, Shawn Robert Gibb
  • ALUMINUM NITRIDE BULK CRYSTALS HAVING HIGH TRANSPARENCY TO ULTRAVIOLET LIGHT AND METHODS OF FORMING THEM
    Publication number: 20190316272
    Abstract: In various embodiments, methods of forming single-crystal AlN include providing a substantially undoped polycrystalline AlN ceramic having an oxygen concentration less than approximately 100 ppm, forming a single-crystal bulk AlN crystal by a sublimation-recondensation process at a temperature greater than approximately 2000° C., and cooling the bulk AlN crystal to a first temperature between approximately 1500° C. and approximately 1800° C. at a first rate less than approximately 250° C./hour.
    Type: Application
    Filed: April 26, 2019
    Publication date: October 17, 2019
    Inventors: Sandra B. Schujman, Shailaja P. Rao, Robert T. Bondokov, Kenneth E. Morgan, Glen A. Slack, Leo J. Schowalter
  • Defect reduction in seeded aluminum nitride crystal growth
    Patent number: 10392722
    Abstract: Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density ?100 cm?2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.
    Type: Grant
    Filed: August 24, 2017
    Date of Patent: August 27, 2019
    Assignee: CRYSTAL IS, INC.
    Inventors: Robert T. Bondokov, Leo J. Schowalter, Kenneth Morgan, Glen A. Slack, Shailaja P. Rao, Shawn Robert Gibb
  • Aluminum nitride bulk crystals having high transparency to ultraviolet light and methods of forming them
    Patent number: 10316428
    Abstract: In various embodiments, methods of forming single-crystal AlN include providing a substantially undoped polycrystalline AlN ceramic having an oxygen concentration less than approximately 100 ppm, forming a single-crystal bulk AlN crystal by a sublimation-recondensation process at a temperature greater than approximately 2000° C., and cooling the bulk AlN crystal to a first temperature between approximately 1500° C. and approximately 1800° C. at a first rate less than approximately 250° C./hour.
    Type: Grant
    Filed: August 15, 2016
    Date of Patent: June 11, 2019
    Assignee: Crystal IS, Inc.
    Inventors: Sandra B. Schujman, Shailaja P. Rao, Robert T. Bondokov, Kenneth E. Morgan, Glen A. Slack, Leo J. Schowalter
  • LARGE, UV-TRANSPARENT ALUMINUM NITRIDE SINGLE CRYSTALS
    Publication number: 20190153618
    Abstract: In various embodiments, single-crystal aluminum nitride boules and substrates having high transparency to ultraviolet light and low defect density are formed. The single-crystal aluminum nitride may function as a platform for the fabrication of light-emitting devices such as light-emitting diodes and lasers.
    Type: Application
    Filed: November 9, 2018
    Publication date: May 23, 2019
    Inventors: Robert T. BONDOKOV, Jianfeng CHEN, Keisuke YAMAOKA, Shichao WANG, Shailaja P. RAO, Takashi SUZUKI, Leo J. SCHOWALTER
  • THERMAL CONTROL FOR FORMATION AND PROCESSING OF ALUMINUM NITRIDE
    Publication number: 20190145020
    Abstract: In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.
    Type: Application
    Filed: November 9, 2018
    Publication date: May 16, 2019
    Inventors: Robert T. BONDOKOV, Jianfeng CHEN, Keisuke YAMAOKA, Shichao WANG, Shailaja P. RAO, Takashi SUZUKI, Leo J. SCHOWALTER
  • System for growth of large aluminum nitride single crystals with thermal-gradient control
    Patent number: 10106913
    Abstract: In various embodiments, non-zero thermal gradients are formed within a growth chamber both substantially parallel and substantially perpendicular to the growth direction during formation of semiconductor crystals, where the ratio of the two thermal gradients (parallel to perpendicular) is less than 10, by, e.g., arrangement of thermal shields outside of the growth chamber.
    Type: Grant
    Filed: January 20, 2017
    Date of Patent: October 23, 2018
    Assignee: CRYSTAL IS, INC.
    Inventors: Robert T. Bondokov, Shailaja P. Rao, Shawn Robert Gibb, Leo J. Schowalter
  • DEFECT REDUCTION IN SEEDED ALUMINUM NITRIDE CRYSTAL GROWTH
    Publication number: 20170350036
    Abstract: Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density?100 cm?2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.
    Type: Application
    Filed: August 24, 2017
    Publication date: December 7, 2017
    Inventors: Robert T. Bondokov, Leo J. Schowalter, Kenneth Morgan, Glen A. Slack, Shailaja P. Rao, Shawn Robert Gibb