Patents by Inventor Solomon Assefa

Solomon Assefa 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: 8841162
    Abstract: A method for forming a photodetector device includes forming an insulator layer on a substrate, forming a germanium (Ge) layer on the insulator layer and a portion of the substrate, forming a second insulator layer on the Ge layer, patterning the Ge layer, forming a capping insulator layer on the second insulator layer and a portion of the first insulator layer, heating the device to crystallize the Ge layer resulting in an single crystalline Ge layer, implanting n-type ions in the single crystalline Ge layer, heating the device to activate n-type ions in the single crystalline Ge layer, and forming electrodes electrically connected to the single crystalline n-type Ge layer.
    Type: Grant
    Filed: December 12, 2013
    Date of Patent: September 23, 2014
    Assignee: International Business Machines Corporation
    Inventors: Solomon Assefa, Jeehwan Kim, Jin-Hong Park, Yurii A. Vlasov
  • Publication number: 20140268120
    Abstract: A method of determining a parameter of a wafer is disclosed. Light is propagated through a waveguide disposed in the wafer. A first measurement of optical power is obtained at a first optical tap coupled to the waveguide and a second measurement of optical power is obtained at a second optical tap coupled to the waveguide using a photodetector placed at a selected location with respect to the wafer. A difference in optical power is determined between the first optical tap and the second optical tap from the first measurement and the second measurement. The parameter of the wafer is determined from the determined difference in optical power.
    Type: Application
    Filed: August 20, 2013
    Publication date: September 18, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, Douglas M. Gill, Jessie C. Rosenberg
  • Publication number: 20140268113
    Abstract: A method of determining a parameter of a wafer is disclosed. Light is propagated through a waveguide disposed in the wafer. A first measurement of optical power is obtained at a first optical tap coupled to the waveguide and a second measurement of optical power is obtained at a second optical tap coupled to the waveguide using a photodetector placed at a selected location with respect to the wafer. A difference in optical power is determined between the first optical tap and the second optical tap from the first measurement and the second measurement. The parameter of the wafer is determined from the determined difference in optical power.
    Type: Application
    Filed: March 15, 2013
    Publication date: September 18, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, Douglas M. Gill, Jessie C. Rosenberg
  • Publication number: 20140217485
    Abstract: A method of forming an integrated photonic semiconductor structure having a photonic device and a CMOS device may include depositing a first silicon nitride layer having a first stress property over the photonic device, depositing an oxide layer having a stress property over the deposited first silicon nitride layer, and depositing a second silicon nitride layer having a second stress property over the oxide layer. The deposited first silicon nitride layer, the oxide layer, and the second silicon nitride layer encapsulate the photonic device.
    Type: Application
    Filed: April 7, 2014
    Publication date: August 7, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, Tymon Barwicz, Swetha Kamlapurkar, Marwan H. Khater, Steven M. Shank, Yurii A. Vlasov
  • Patent number: 8796041
    Abstract: A semiconductor device includes a substrate including an M2 patterned area. A VA pillar structure is formed over the M2 patterned area. The VA pillar structure includes a substractively patterned metal layer. The VA pillar structure is a sub-lithographic contact. An MTJ stack is formed over the oxide layer and the metal layer of the VA pillar. A size of the MTJ stack and a shape anisotropy of the MTJ stack are independent of a size and a shape anisotropy of the sub-lithographic contact.
    Type: Grant
    Filed: August 28, 2009
    Date of Patent: August 5, 2014
    Assignee: International Business Machines Corporation
    Inventors: Solomon Assefa, Michael C. Gaidis, Eric A. Joseph, Eugene J. O'Sullivan
  • Patent number: 8796747
    Abstract: A semiconductor chip having a photonics device and a CMOS device which includes a photonics device portion and a CMOS device portion on a semiconductor chip; a metal or polysilicon gate on the CMOS device portion, the metal or polysilicon gate having a gate extension that extends toward the photonics device portion; a germanium gate on the photonics device portion such that the germanium gate is coplanar with the metal or polysilicon gate, the germanium gate having a gate extension that extends toward the CMOS device portion, the germanium gate extension and metal or polysilicon gate extension joined together to form a common gate; spacers formed on the germanium gate and the metal or polysilicon gate; and nitride encapsulation formed on the germanium gate. A method is also disclosed pertaining to fabricating the semiconductor chip.
    Type: Grant
    Filed: January 8, 2013
    Date of Patent: August 5, 2014
    Assignee: International Business Machines Corporation
    Inventors: Solomon Assefa, William M. J. Green, Steven M. Shank, Yurii A. Vlasov
  • Publication number: 20140209985
    Abstract: A method of forming an integrated photonic semiconductor structure having a photodetector device and a CMOS device may include depositing a dielectric stack over the photodetector device such that the dielectric stack encapsulates the photodetector. An opening is etched into the dielectric stack down to an upper surface of a region of an active area of the photodetector. A first metal layer is deposited directly onto the upper surface of the region of the active area via the opening such that the first metal layer may cover the region of the active area. Within the same mask level, a plurality of contacts including a second metal layer are located on the first metal layer and on the CMOS device. The first metal layer isolates the active area from the occurrence of metal intermixing between the second metal layer and the active area of the photodetector.
    Type: Application
    Filed: March 27, 2014
    Publication date: July 31, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, Jeffrey P. Gambino, Steven M. Shank
  • Publication number: 20140197507
    Abstract: A method of forming an integrated photonic semiconductor structure having a photodetector and a CMOS device may include forming the CMOS device on a first silicon-on-insulator region, forming a silicon optical waveguide on a second silicon-on-insulator region, and forming a shallow trench isolation (STI) region surrounding the silicon optical waveguide such that the shallow trench isolation electrically isolating the first and second silicon-on-insulator region. Within a first region of the STI region, a first germanium material is deposited adjacent a first side wall of the semiconductor optical waveguide. Within a second region of the STI region, a second germanium material is deposited adjacent a second side wall of the semiconductor optical waveguide, whereby the second side wall opposes the first side wall. The first and second germanium material form an active region that evanescently receives propagating optical signals from the first and second side wall of the semiconductor optical waveguide.
    Type: Application
    Filed: January 15, 2013
    Publication date: July 17, 2014
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: SOLOMON ASSEFA, WILLIAM M. GREEN, STEVEN M. SHANK, YURII A. VLASOV
  • Publication number: 20140191302
    Abstract: A semiconductor chip having a photonics device and a CMOS device which includes a photonics device portion and a CMOS device portion on a semiconductor chip; a metal or polysilicon gate on the CMOS device portion, the metal or polysilicon gate having a gate extension that extends toward the photonics device portion; a germanium gate on the photonics device portion such that the germanium gate is coplanar with the metal or polysilicon gate, the germanium gate having a gate extension that extends toward the CMOS device portion, the germanium gate extension and metal or polysilicon gate extension joined together to form a common gate; spacers formed on the germanium gate and the metal or polysilicon gate; and nitride encapsulation formed on the germanium gate. A method is also disclosed pertaining to fabricating the semiconductor chip.
    Type: Application
    Filed: January 8, 2013
    Publication date: July 10, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, William M.J. Green, Steven M. Shank, Yurii A. Vlasov
  • Publication number: 20140191326
    Abstract: A semiconductor chip having a photonics device and a CMOS device which includes a photonics device portion and a CMOS device portion on a semiconductor chip; a metal or polysilicon gate on the CMOS device portion, the metal or polysilicon gate having a gate extension that extends toward the photonics device portion; a germanium gate on the photonics device portion such that the germanium gate is coplanar with the metal or polysilicon gate, the germanium gate having a gate extension that extends toward the CMOS device portion, the germanium gate extension and metal or polysilicon gate extension joined together to form a common gate; spacers formed on the germanium gate and the metal or polysilicon gate; and nitride encapsulation formed on the germanium gate.
    Type: Application
    Filed: August 30, 2013
    Publication date: July 10, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, William M. J. Green, Steven M. Shank, Yurii A. Vlasov
  • Patent number: 8772902
    Abstract: Line trenches are formed in a stack of a bulk semiconductor substrate and an oxygen-impermeable layer such that the depth of the trenches in the bulk semiconductor substrate is greater than the lateral spacing between a pair of adjacently located line trenches. Oxygen-impermeable spacers are formed on sidewalls of the line trenches. An isotropic etch, either alone or in combination with oxidation, removes a semiconductor material from below the oxygen-impermeable spacers to expand the lateral extent of expanded-bottom portions of the line trenches, and to reduce the lateral spacing between adjacent expanded-bottom portions. The semiconductor material around the bottom portions is oxidized to form a semiconductor oxide portion that underlies multiple oxygen-impermeable spacers. Semiconductor-on-insulator (SOI) portions are formed above the semiconductor oxide portion and within the bulk semiconductor substrate.
    Type: Grant
    Filed: April 19, 2012
    Date of Patent: July 8, 2014
    Assignee: International Business Machines Corporation
    Inventors: Solomon Assefa, William M. J. Green, Marwan H. Khater, Yurii A. Vlasov
  • Publication number: 20140185981
    Abstract: A method of forming an integrated photonic semiconductor structure having a photonic device and adjacent CMOS devices may include depositing a first silicon nitride layer over the adjacent CMOS devices and depositing an oxide layer over the first silicon nitride layer, wherein the oxide layer conformally covers the first silicon nitride layer and the underlying adjacent CMOS devices to form a substantially planarized surface over the adjacent CMOS devices. A second silicon nitride layer is then deposited over the oxide layer and a region corresponding to forming the photonic device. A germanium layer is deposited over the oxide layer and the region corresponding to forming the photonic device. The germanium layer deposited over the adjacent CMOS devices is etched to form a germanium active layer within the photonic region, whereby the oxide layer and the second silicon nitride layer protect the adjacent CMOS devices during the etching of the germanium.
    Type: Application
    Filed: January 2, 2013
    Publication date: July 3, 2014
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Solomon Assefa, Marwan H. Khater, Edward W. Kiewra, Steven M. Shank
  • Patent number: 8765502
    Abstract: A method of forming an integrated photonic semiconductor structure having a photodetector device and a CMOS device may include depositing a dielectric stack over the photodetector device such that the dielectric stack encapsulates the photodetector. An opening is etched into the dielectric stack down to an upper surface of a region of an active area of the photodetector. A first metal layer is deposited directly onto the upper surface of the region of the active area via the opening such that the first metal layer may cover the region of the active area. Within the same mask level, a plurality of contacts including a second metal layer are located on the first metal layer and on the CMOS device. The first metal layer isolates the active area from the occurrence of metal intermixing between the second metal layer and the active area of the photodetector.
    Type: Grant
    Filed: July 30, 2012
    Date of Patent: July 1, 2014
    Assignee: International Business Machines Corporation
    Inventors: Solomon Assefa, Jeffrey P. Gambino, Steven M. Shank
  • Patent number: 8765536
    Abstract: A method of forming an integrated photonic semiconductor structure having a photonic device and a CMOS device may include depositing a first silicon nitride layer having a first stress property over the photonic device, depositing an oxide layer having a stress property over the deposited first silicon nitride layer, and depositing a second silicon nitride layer having a second stress property over the oxide layer. The deposited first silicon nitride layer, the oxide layer, and the second silicon nitride layer encapsulate the photonic device.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: July 1, 2014
    Assignee: International Business Machines Corporation
    Inventors: Solomon Assefa, Tymon Barwicz, Swetha Kamlapurkar, Marwan H. Khater, Steven M. Shank, Yurii A. Vlasov
  • Publication number: 20140134789
    Abstract: A method for forming a photodetector device includes forming an insulator layer on a substrate, forming a germanium (Ge) layer on the insulator layer and a portion of the substrate, forming a second insulator layer on the Ge layer, patterning the Ge layer, forming a capping insulator layer on the second insulator layer and a portion of the first insulator layer, heating the device to crystallize the Ge layer resulting in an single crystalline Ge layer, implanting n-type ions in the single crystalline Ge layer, heating the device to activate n-type ions in the single crystalline Ge layer, and forming electrodes electrically connected to the single crystalline n-type Ge layer.
    Type: Application
    Filed: December 12, 2013
    Publication date: May 15, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, Jeehwan Kim, Jin-Hong Park, Yurii A. Vlasov
  • Publication number: 20140134790
    Abstract: A method for forming a photodetector device includes forming an insulator layer on a substrate, forming a germanium (Ge) layer on the insulator layer and a portion of the substrate, forming a second insulator layer on the Ge layer, patterning the Ge layer, forming a capping insulator layer on the second insulator layer and a portion of the first insulator layer, heating the device to crystallize the Ge layer resulting in an single crystalline Ge layer, implanting n-type ions in the single crystalline Ge layer, heating the device to activate n-type ions in the single crystalline Ge layer, and forming electrodes electrically connected to the single crystalline n-type Ge layer.
    Type: Application
    Filed: December 12, 2013
    Publication date: May 15, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, Jeehwan Kim, Jin-Hong Park, Yurii A. Vlasov
  • Publication number: 20140127878
    Abstract: Photonic devices are created by laterally growing a semiconductor material (i.e., a localized semiconductor-on-insulator layer) over a localized buried oxide (BOX) created in a semiconductor by either a trench isolation process or thermal oxidation. In one embodiment, and after trench formation in a semiconductor substrate, the trench is filled with oxide to create a localized BOX. The top surface of the BOX is recessed to depth below the topmost surface of the semiconductor substrate to expose sidewall surfaces of the semiconductor substrate within each trench. A semiconductor material is then epitaxially grown from the exposed sidewall surfaces of the semiconductor substrate.
    Type: Application
    Filed: November 2, 2012
    Publication date: May 8, 2014
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Solomon Assefa, William M. Green, Marwan H. Khater, Yurri A. Vlasov
  • Publication number: 20140127877
    Abstract: Photonic SOI devices are formed by lateral epitaxy of a deposited non-crystalline semiconductor layer over a localized buried oxide created by a trench isolation process or by thermal oxidation. Specifically, and after forming a trench into a semiconductor substrate, the trench can be filled with an oxide by a deposition process or a thermal oxidation can be performed to form a localized buried oxide within the semiconductor substrate. In some embodiments, the oxide can be recessed to expose sidewall surfaces of the semiconductor substrate. Next, a non-crystalline semiconductor layer is formed and then a solid state crystallization is preformed which forms a localized semiconductor-on-insulator layer. During the solid state crystallization process portions of the non-crystalline semiconductor layer that are adjacent exposed sidewall surfaces of the substrate are crystallized.
    Type: Application
    Filed: November 2, 2012
    Publication date: May 8, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, William M. Green, Marwan H. Khater, Yurii A. Vlasov
  • Publication number: 20140091374
    Abstract: A method of forming an integrated photonic semiconductor structure having a photonic device and a CMOS device may include depositing a first silicon nitride layer having a first stress property over the photonic device, depositing an oxide layer having a stress property over the deposited first silicon nitride layer, and depositing a second silicon nitride layer having a second stress property over the oxide layer. The deposited first silicon nitride layer, the oxide layer, and the second silicon nitride layer encapsulate the photonic device.
    Type: Application
    Filed: September 28, 2012
    Publication date: April 3, 2014
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Solomon Assefa, Tymon Barwicz, Swetha Kamlapurkar, Marwan H. Khater, Steven M. Shank, Yurii A. Vlasov
  • Publication number: 20140080269
    Abstract: Disclosed are process enhancements to fully integrate the processing of a photonics device into a CMOS manufacturing process flow. A CMOS wafer may be divided into different portions. One of the portions is for the CMOS devices and one or more other portions are for the photonics devices. The photonics devices include a ridged waveguide and a germanium photodetector. The germanium photodetector may utilize a seeded crystallization from melt process so there is more flexibility in the processing of the germanium photodetector.
    Type: Application
    Filed: November 20, 2013
    Publication date: March 20, 2014
    Applicant: International Business Machines Corporation
    Inventors: Solomon Assefa, William M.J. Green, Yurii A. Vlasov, Min Yang