Patents by Inventor Davood Shahrjerdi

Davood Shahrjerdi 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: 9202959
    Abstract: A photovoltaic device and method include a crystalline substrate and an emitter contact portion formed in contact with the substrate. A back-surface-field junction includes a homogeneous junction layer formed in contact with the crystalline substrate and having a same conductivity type and a higher active doping density than that of the substrate. The homogeneous junction layer includes a thickness less than a diffusion length of minority carriers in the homogeneous junction layer. A passivation layer is formed in contact with the homogeneous junction layer opposite the substrate, which is either undoped or has the same conductivity type as that of the substrate.
    Type: Grant
    Filed: September 25, 2012
    Date of Patent: December 1, 2015
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Tze-Chiang Chen, Bahman Hekmatshoartabari, Devendra K. Sadana, Davood Shahrjerdi
  • Publication number: 20150340532
    Abstract: A method of forming a semiconductor material of a photovoltaic device that includes providing a surface of a hydrogenated amorphous silicon containing material, and annealing the hydrogenated amorphous silicon containing material in a deuterium containing atmosphere. Deuterium from the deuterium-containing atmosphere is introduced to the lattice of the hydrogenated amorphous silicon containing material through the surface of the hydrogenated amorphous silicon containing material. In some embodiments, the deuterium that is introduced to the lattice of the hydrogenated amorphous silicon containing material increases the stability of the hydrogenated amorphous silicon containing material.
    Type: Application
    Filed: August 3, 2015
    Publication date: November 26, 2015
    Inventors: Bahman Hekmatshoar-Tabari, Marinus Hopstaken, Dae-Gyu Park, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150340495
    Abstract: Group IV semiconductor devices can be formed on a semiconductor-on-insulator substrate including a handle substrate containing a group IV semiconductor material. A cavity is formed to physically expose a top surface of the handle substrate through a stack, from bottom to top, of a buried insulator layer, a doped semiconductor material portion in a top semiconductor layer, and a dielectric material layer. A gate dielectric is formed around the cavity by a conformal deposition of a dielectric material layer and an anisotropic etch. A lower active region, a channel region, and an upper active region are formed by selective epitaxy processes in, and/or above, the trench and from the top surface of the handle substrate. The selective epitaxy processes deposit a compound semiconductor material. The doped semiconductor material portion functions as the gate of a vertical compound semiconductor field effect transistor.
    Type: Application
    Filed: May 21, 2014
    Publication date: November 26, 2015
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Anirban Basu, Bahman Hekmatshoartabari, Davood Shahrjerdi
  • Publication number: 20150333187
    Abstract: Junction field effect transistors are provided which include a gate junction located on a surface of a crystalline semiconductor material of a first conductivity type. The gate junction can be selected from one of a doped hydrogenated crystalline semiconductor material layer portion of a second conductivity type which is opposite the first conductivity type, a doped hydrogenated non-crystalline semiconductor material layer portion of a second conductivity type which is opposite the first conductivity type, and a Schottky contact.
    Type: Application
    Filed: July 27, 2015
    Publication date: November 19, 2015
    Inventors: Bahman Hekmatshoar-Tabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150318416
    Abstract: A method for forming a multi-junction photovoltaic device includes providing a germanium layer and etching pyramidal shapes in the germanium layer such that (111) facets are exposed to form a textured surface. A first p-n junction is formed on or over the textured surface from III-V semiconductor materials. Another p-n junction is formed over the first p-n junction from III-V semiconductor materials and follows the textured surface.
    Type: Application
    Filed: July 13, 2015
    Publication date: November 5, 2015
    Inventors: BAHMAN HEKMATSHOARTABARI, ALI KHAKIFIROOZ, GHAVAM G. SHAHIDI, DAVOOD SHAHRJERDI
  • Publication number: 20150318425
    Abstract: A method for fabricating a device with integrated photovoltaic cells includes supporting a semiconductor substrate on a first handle substrate and doping the semiconductor substrate to form doped alternating regions with opposite conductivity. A doped layer is formed over a first side the semiconductor substrate. A conductive material is patterned over the doped layer to form conductive islands such that the conductive islands are aligned with the alternating regions to define a plurality of photovoltaic cells connected in series on a monolithic structure.
    Type: Application
    Filed: July 10, 2015
    Publication date: November 5, 2015
    Inventors: STEPHEN W. BEDELL, BAHMAN HEKMATSHOARTABARI, DEVENDRA K. SADANA, GHAVAM G. SHAHIDI, DAVOOD SHAHRJERDI
  • Patent number: 9178042
    Abstract: A method for forming a thin film transistor includes joining a crystalline substrate to an insulating substrate. A doped layer is deposited on the crystalline substrate, and the doped layer is patterned to form source and drain regions. The crystalline substrate is patterned to form an active area such that a conductive channel is formed in the crystalline substrate between the source and drain regions. A gate stack is formed between the source and drain regions, and contacts are formed to the source and drain regions and the gate stack through a passivation layer.
    Type: Grant
    Filed: January 8, 2013
    Date of Patent: November 3, 2015
    Assignee: GLOBALFOUNDRIES INC
    Inventors: Bahman Hekmatshoartabari, Ning Li, Devendra K. Sadana, Davood Shahrjerdi
  • Patent number: 9166072
    Abstract: Photovoltaic structures are provided with field-effect inversion/accumulation layers as emitter layers induced by work-function differences between gate conductor layers and substrates thereof. Localized contact regions are in electrical communication with the gate conductors of such structures for repelling minority carriers. Such localized contact regions may include doped crystalline or polycrystalline silicon regions between the gate conductor and silicon absorption layers. Fabrication of the structures can be conducted without alignment between metal contacts and the localized contact regions or high temperature processing.
    Type: Grant
    Filed: September 4, 2012
    Date of Patent: October 20, 2015
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Wilfried E. Haensch, Bahman Hekmatshoartabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150287740
    Abstract: A semiconductor device including at least one semiconductor device on a first surface of a dielectric layer, and at least one stressor structure having an intrinsic stress on a second surface of the dielectric layer. The at least one semiconductor device and the at least one stressor structure are present on opposing sides of the dielectric layer. The at least one stressor structure induces a stress on the at least one semiconductor device opposite the intrinsic stress.
    Type: Application
    Filed: April 2, 2014
    Publication date: October 8, 2015
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Stephen W. Bedell, Wilfried E. Haensch, Bahman Hekmatshoartabari, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150279913
    Abstract: A method of forming an active matrix pixel that includes forming a driver device including contact regions deposited using a low temperature deposition process on a first portion of an insulating substrate. An electrode of an organic light emitting diode is formed on a second portion of the insulating substrate. The electrode is in electrical communication to receive an output from the driver device. At least one passivation layer is formed over the driver device. A switching device comprising at least one amorphous semiconductor layer is formed on the at least one passivation layer over the driver device.
    Type: Application
    Filed: March 26, 2014
    Publication date: October 1, 2015
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Stephen M. Gates, Bahman Hekmatshoartabari, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150279936
    Abstract: A planar semiconductor device including a semiconductor on insulator (SOI) substrate with source and drain portions having a thickness of less than 10 nm that are separated by a multi-layered strained channel. The multi-layer strained channel of the SOI layer includes a first layer with a first lattice dimension that is present on the buried dielectric layer of the SOI substrate, and a second layer of a second lattice dimension that is in direct contact with the first layer of the multi-layer strained channel portion. A functional gate structure is present on the multi-layer strained channel portion of the SOI substrate. The semiconductor device having the multi-layered channel may also be a finFET semiconductor device.
    Type: Application
    Filed: June 12, 2015
    Publication date: October 1, 2015
    Inventors: Thomas N. Adam, Kangguo Cheng, Ali Khakifirooz, Alexander Reznicek, Davood Shahrjerdi
  • Publication number: 20150276653
    Abstract: A sensing apparatus includes a device containing microwells and a switched capacitor circuit in which at least one of the sensing/storage capacitors is a capacitor that extends perpendicularly with respect to a semiconductor device layer containing field effect transistors. Capacitor structures extend into microwells or within a doped layer on a handle substrate. Ion generation within the microwells is sensed using the circuit.
    Type: Application
    Filed: March 30, 2014
    Publication date: October 1, 2015
    Applicant: International Business Machines Corporation
    Inventors: Bahman Hekmatshoartabari, Ali Khakifirooz, Ghavam G. Shahidi, Davood Shahrjerdi
  • Patent number: 9147715
    Abstract: Bipolar junction transistors including inorganic channels and organic emitter junctions are used in some applications for forming high resolution active matrix displays. Arrays of such bipolar junction transistors are electrically connected to thin film switching transistors and provide high drive currents for passive devices such as organic light emitting diodes.
    Type: Grant
    Filed: February 19, 2014
    Date of Patent: September 29, 2015
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ali Afzali-Ardakani, Bahman Hekmatshoartabari, Tak H. Ning, Davood Shahrjerdi
  • Publication number: 20150270187
    Abstract: Fabrication methods are disclosed that facilitate the production of electronic structures that are both flexible and stretchable to conform to non-planar (e.g. curved) surfaces without suffering functional damage due to excessive strain. Electronic structures including CMOS devices are provided that can be stretched or squeezed within acceptable limits without failing or breaking. The methods disclosed herein further facilitate the production of flexible, stretchable electronic structures having multiple levels of intra-chip connectors. Such connectors are formed through deposition and photolithographic patterning (back end of the line processing) and can be released following transfer of the electronic structures to flexible substrates.
    Type: Application
    Filed: June 6, 2015
    Publication date: September 24, 2015
    Inventors: Stephen W. Bedell, Wilfried E. Haensch, Bahman Hekmatshoartabari, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150270424
    Abstract: A photovoltaic device and method include a substrate coupled to an emitter side structure on a first side of the substrate and a back side structure on a side opposite the first side of the substrate. The emitter side structure or the back side structure include layers alternating between wide band gap layers and narrow band gap layers to provide a multilayer contact with an effectively increased band offset with the substrate and/or an effectively higher doping level over a single material contact. An emitter contact is coupled to the emitter side structure on a light collecting end portion of the device. A back contact is coupled to the back side structure opposite the light collecting end portion.
    Type: Application
    Filed: June 4, 2015
    Publication date: September 24, 2015
    Inventors: BAHMAN HEKMATSHOAR-TABARI, DEVENDRA K. SADANA, GHAVAM G. SHAHIDI, DAVOOD SHAHRJERDI
  • Publication number: 20150270326
    Abstract: A hybrid integrated circuit device includes a semiconductor-on-insulator substrate having a base substrate, a semiconductor layer and a dielectric layer disposed therebetween, the base substrate being reduced in thickness. First devices are formed in the semiconductor layer, the first devices being connected to first metallizations on a first side of the dielectric layer. Second devices are formed in the base substrate, the second devices being connected to second metallizations formed on a second side of the dielectric layer opposite the first side. A through via connection is configured to connect the first metallizations to the second metallizations through the dielectric layer. Pixel circuits and methods are also disclosed.
    Type: Application
    Filed: May 20, 2015
    Publication date: September 24, 2015
    Inventors: Bahman Hekmatshoartabari, Tak H. Ning, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150270380
    Abstract: A circuit includes a first field effect transistor having a gate, a first drain-source terminal, and a second drain-source terminal; and a second field effect transistor having a gate, a first drain-source terminal, and a second drain-source terminal. The second field effect transistor and the first field effect transistor are of the same type, i.e., both re-channel transistors or both p-channel transistors. The second drain-source terminal of the first field effect transistor is coupled to the first drain-source terminal of the second field effect transistor; and the gate of the second field effect transistor is coupled to the first drain-source terminal of the second field effect transistor. The resulting three-terminal device can be substituted for a single field effect transistor that would otherwise suffer breakdown under proposed operating conditions.
    Type: Application
    Filed: June 6, 2015
    Publication date: September 24, 2015
    Inventors: Stephen W. Bedell, Bahman Hekmatshoartabari, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150263064
    Abstract: A method for forming a back-illuminated image sensor includes forming a higher doped crystalline layer on a crystalline substrate, growing a lower doped crystalline layer on the higher doped crystalline layer and forming a photodiode and component circuitry from the lower doped crystalline layer. Metallization structures are formed to make connections to and between components. The crystalline substrate is removed to expose the higher doped crystalline layer. An optical component structure is provided on an exposed surface of the higher doped crystalline layer to receive light therein such that the higher doped crystalline layer provides a passivation layer for the photodiode and the component circuitry.
    Type: Application
    Filed: May 29, 2015
    Publication date: September 17, 2015
    Inventors: Stephen W. Bedell, Bahman Hekmatshoartabari, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150263129
    Abstract: Heterojunction bipolar transistors are provided that include at least one contact (e.g., collector, emitter, and/or base) formed by a heterojunction between a crystalline semiconductor material and a doped non-crystalline semiconductor material layer. An interfacial intrinsic non-crystalline semiconductor material layer is present at the heterojunction between the crystalline semiconductor material and the doped non-crystalline semiconductor material layer. The presence of the interfacial intrinsic non-crystalline semiconductor material layer improves the surface passivation of the crystalline semiconductor material by reducing the interface defect density at the heterojunction.
    Type: Application
    Filed: May 29, 2015
    Publication date: September 17, 2015
    Inventors: Bahman Hekmatshoar-Tabari, Tak H. Ning, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
  • Publication number: 20150263143
    Abstract: Heterojunction bipolar transistors are provided that include at least one contact (e.g., collector, emitter, and/or base) formed by a heterojunction between a crystalline semiconductor material and a doped non-crystalline semiconductor material layer. An interfacial intrinsic non-crystalline semiconductor material layer is present at the heterojunction between the crystalline semiconductor material and the doped non-crystalline semiconductor material layer. The presence of the interfacial intrinsic non-crystalline semiconductor material layer improves the surface passivation of the crystalline semiconductor material by reducing the interface defect density at the heterojunction.
    Type: Application
    Filed: May 29, 2015
    Publication date: September 17, 2015
    Inventors: Bahman Hekmatshoar-Tabari, Tak H. Ning, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi