Patents by Inventor Alexander A. Demkov

Alexander A. Demkov 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: 20230132224
    Abstract: Electro-optic modulators and related devices and methods. The method includes forming a silicon dioxide layer on a silicon substrate. The method includes forming a doped silicon layer in or on the silicon dioxide layer. The method includes forming alternating layers of functional transition metal oxides (TMOs) on the doped silicon layer. Design parameters can be optimized to create realizable devices that minimize the energy consumption of, for example, a SrTiO3/LaAlO3 electro-optic modulator while maximizing electro-optic performance (e.g., modulation energies on the order of tens of pJ/bit).
    Type: Application
    Filed: March 8, 2021
    Publication date: April 27, 2023
    Inventors: Alexander A. Demkov, John Elliott Ortmann, Jr., Agham Posadas
  • Patent number: 11561421
    Abstract: Various embodiments of the present technology enable growth of a-axis oriented barium titanate (BTO) films by inserting a relaxed strain control layer having a larger lattice constant than the c-axis of BTO and a similar thermal expansion mismatch. As a result, in-plane tensile stress causes BTO to grow with its ferroelectric polarization in-plane. Some embodiments allow for BTO films to immediately be grown on silicon with a-axis orientation, and without the need to create thick layers for relaxation. Using various embodiments of the present technology, the BTO can be grown in-plane with minimal dislocation density that is confined to the interface region.
    Type: Grant
    Filed: June 25, 2020
    Date of Patent: January 24, 2023
    Assignee: Board of Regents, The University of Texas System
    Inventors: Alexander A. Demkov, Marc Reynaud, Agham Posadas
  • Publication number: 20220268996
    Abstract: Various embodiments provide for systems and techniques for the successful fabrication of metal oxide (TMO)-on-glass layer stacks via direct deposition. The resulting samples feature epitaxial, strontium titanate (STO) or barium titanate (BTO) films on silicon dioxide (SiO2) layers, forming STO- or BTO-buffered SiO2 pseudo-substrates. As the integration of TMO films on silicon rely on an STO or BTO buffer layer, a wide variety of TMO-based integrated devices (e.g., circuits, waveguides, etc.) can be fabricated from the TMO-on-glass platform of the present technology. Moreover, the STO, or the BTO, survives the fabrication process without a corresponding degradation of crystalline quality, as evidenced by various objective measures.
    Type: Application
    Filed: April 29, 2022
    Publication date: August 25, 2022
    Inventors: Alexander A. Demkov, John Elliott Ortmann, Agham Posadas
  • Publication number: 20220130866
    Abstract: Some embodiments of the present technology simplify the process of producing SOI wafers significantly compared to traditional methods. Furthermore, various embodiments provide a route for the integration of perovskite transition metal oxide thin films with different properties into SOI wafers. As such films display a wide array of novel electronic, magnetic, and optical phenomena, their integration into technologically-relevant SOI wafers will likely allow for the construction of a wide array of novel devices.
    Type: Application
    Filed: March 4, 2020
    Publication date: April 28, 2022
    Inventors: Alexander A. Demkov, J. Elliott Ortmann, Agham Posadas
  • Publication number: 20200409190
    Abstract: Various embodiments of the present technology enable growth of a-axis oriented barium titanate (BTO) films by inserting a relaxed strain control layer having a larger lattice constant than the c-axis of BTO and a similar thermal expansion mismatch. As a result, in-plane tensile stress causes BTO to grow with its ferroelectric polarization in-plane. Some embodiments allow for BTO films to immediately be grown on silicon with a-axis orientation, and without the need to create thick layers for relaxation. Using various embodiments of the present technology, the BTO can be grown in-plane with minimal dislocation density that is confined to the interface region.
    Type: Application
    Filed: June 25, 2020
    Publication date: December 31, 2020
    Inventors: Alexander A. Demkov, Marc Reynaud, Agham Posadas
  • Patent number: 9293697
    Abstract: A spintronic device and a method for making said spintronic device. The spintronic device includes an epitaxial crystalline ferromagnetic oxide formed directly on the semiconductor material thereby allowing spin-polarized current to be efficiently injected from the ferromagnetic oxide into the semiconductor material. A host crystal lattice includes multiple sets of stacked oxide layers of material A and B of a perovskite structure with a formula of ABO3. After an oxide layer of B is grown, magnetic ions are introduced to intermix with the B material, which may replace some of the ions of the B material. The process of growing additional stacked oxide layers of material A and B and introducing further magnetic ions after the deposition of the oxide layer of B continues until enough magnetic ions are sufficiently close to one another that they align in the same direction thereby forming a ferromagnetic oxide on the semiconductor material.
    Type: Grant
    Filed: March 6, 2015
    Date of Patent: March 22, 2016
    Assignee: Board of Regents, The University of Texas System
    Inventors: Alexander A. Demkov, Agham-Bayan S. Posadas
  • Publication number: 20150333253
    Abstract: A spintronic device and a method for making said spintronic device. The spintronic device includes an epitaxial crystalline ferromagnetic oxide formed directly on the semiconductor material thereby allowing spin-polarized current to be efficiently injected from the ferromagnetic oxide into the semiconductor material. A host crystal lattice includes multiple sets of stacked oxide layers of material A and B of a perovskite structure with a formula of ABO3. After an oxide layer of B is grown, magnetic ions are introduced to intermix with the B material, which may replace some of the ions of the B material. The process of growing additional stacked oxide layers of material A and B and introducing further magnetic ions after the deposition of the oxide layer of B continues until enough magnetic ions are sufficiently close to one another that they align in the same direction thereby forming a ferromagnetic oxide on the semiconductor material.
    Type: Application
    Filed: March 6, 2015
    Publication date: November 19, 2015
    Inventors: Alexander A. Demkov, Agham-Bayan S. Posadas
  • Patent number: 9023662
    Abstract: A spintronic device and a method for making said spintronic device. The spintronic device includes an epitaxial crystalline ferromagnetic oxide formed directly on the semiconductor material thereby allowing spin-polarized current to be efficiently injected from the ferromagnetic oxide into the semiconductor material. A host crystal lattice includes multiple sets of stacked oxide layers of material A and B of a perovskite structure with a formula of ABO3. After an oxide layer of B is grown, magnetic ions are introduced to intermix with the B material, which may replace some of the ions of the B material. The process of growing additional stacked oxide layers of material A and B and introducing further magnetic ions after the deposition of the oxide layer of B continues until enough magnetic ions are sufficiently close to one another that they align in the same direction thereby forming a ferromagnetic oxide on the semiconductor material.
    Type: Grant
    Filed: May 7, 2012
    Date of Patent: May 5, 2015
    Assignee: Board of Regents, The University of Texas System
    Inventors: Alexander A. Demkov, Agham-Bayan S. Posadas
  • Publication number: 20120286383
    Abstract: A spintronic device and a method for making said spintronic device. The spintronic device includes an epitaxial crystalline ferromagnetic oxide formed directly on the semiconductor material thereby allowing spin-polarized current to be efficiently injected from the ferromagnetic oxide into the semiconductor material. A host crystal lattice includes multiple sets of stacked oxide layers of material A and B of a perovskite structure with a formula of ABO3. After an oxide layer of B is grown, magnetic ions are introduced to intermix with the B material, which may replace some of the ions of the B material. The process of growing additional stacked oxide layers of material A and B and introducing further magnetic ions after the deposition of the oxide layer of B continues until enough magnetic ions are sufficiently close to one another that they align in the same direction thereby forming a ferromagnetic oxide on the semiconductor material.
    Type: Application
    Filed: May 7, 2012
    Publication date: November 15, 2012
    Applicant: BOARD OF REGENTS, THE UNIVERSITY OF TEXAS SYSTEM
    Inventors: Alexander A. Demkov, Agham-Bayan S. Posadas
  • Patent number: 7365410
    Abstract: A method for forming a semiconductor structure including providing a semiconductor substrate, forming a metallic buffer layer over the semiconductor substrate, forming an amorphous semiconductor layer over the metallic buffer layer, and recrystallizing the amorphous semiconductor layer to form a crystalline semiconductor layer. A semiconductor structure includes a semiconductor substrate, a buffer layer comprising at least one of silicide and germanide formed over the semiconductor substrate, and a crystalline semiconductor layer formed over the metallic buffer layer.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: April 29, 2008
    Assignee: Freescale, Semiconductor, Inc.
    Inventors: Alexander A. Demkov, William J. Taylor, Jr.
  • Publication number: 20070218640
    Abstract: A semiconductor device having a gate with a thin conductive layer is described. As the physical dimensions of semiconductor devices are scaled below the sub-micron regime, very thin gate dielectrics are used. One problem encountered with very thin gate dielectrics is that the carriers can tunnel through the gate dielectric material, thus increasing the undesirable leakage current in the device. By using a thin layer for conductive layer, quantum confinement of carriers within conductive layer can be induced. This quantum confinement removes modes which are propagating in the direction normal to the interfacial plane from the Fermi level. Thus, the undesirable leakage current in the device can be reduced. Additional conductive layers may be used to provide more carriers.
    Type: Application
    Filed: May 23, 2007
    Publication date: September 20, 2007
    Applicant: Freescale Semiconductor, Inc.
    Inventors: Sinan Goktepeli, Alexander Demkov, Marius Orlowski
  • Patent number: 7235847
    Abstract: A semiconductor device (10) having a gate (16, 18 or 16, 18, 26, 28) with a thin conductive layer (18) is described. As the physical dimensions of semiconductor devices are scaled below the sub-micron regime, very thin gate dielectrics (16) are used. One problem encountered with very thin gate dielectrics is that the carriers can tunnel through the gate dielectric material, thus increasing the undesirable leakage current in the device. By using a thin layer for conductive layer (18), quantum confinement of carriers within conductive layer (18) can be induced. This quantum confinement removes modes which are propagating in the direction normal to the interfacial plane 15 from the Fermi level. Thus, the undesirable leakage current in the device (10) can be reduced. Additional conductive layers (e.g. 28) may be used to provide more carriers.
    Type: Grant
    Filed: September 17, 2004
    Date of Patent: June 26, 2007
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Sinan Goktepeli, Alexander A. Demkov, Marius K. Orlowski
  • Patent number: 7141857
    Abstract: Semiconductor structures and processes for fabricating semiconductor structures comprising hafnium oxide layers modified with lanthanum oxide or a lanthanide-series metal oxide are provided. A semiconductor structure in accordance with an embodiment of the invention comprises an amorphous layer of hafnium oxide overlying a substrate. A lanthanum-containing dopant or a lanthanide-series metal-containing dopant is comprised within the amorphous layer of hafnium oxide. The process comprises growing an amorphous layer of hafnium oxide overlying a substrate. The amorphous layer of hafnium oxide is doped with a dopant having the chemical formulation LnOx, where Ln is lanthanum, a lanthanide-series metal, or a combination thereof, and X is any number greater than zero. The doping step may be performed during or after growth of the amorphous layer of hafnium oxide.
    Type: Grant
    Filed: June 30, 2004
    Date of Patent: November 28, 2006
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Zhiyi Yu, Jay A. Curless, Yong Liang, Alexandra Navrotsky, Sergey Ushakov, Bich-Yen Nguyen, Alexander Demkov
  • Patent number: 7091568
    Abstract: A mixture of materials can be used within a layer of an electronic device to improve electrical and physical properties of the layer. In one set of embodiments, the layer can be a dielectric layer, such as a gate dielectric layer or a capacitor dielectric layer. The dielectric layer can include O, and two or more dissimilar metallic elements. In one specific embodiment, two dissimilar elements may have the same single oxidation state and be miscible within each other. In one embodiment, the dielectric layer can include an alloy of (HfO2)(1-x)(ZrO2)x, wherein x is between 0 and 1. Each of Hf and Zr has a single oxidation state of +4. Other combinations are possible. Improved electrical and physical properties can include better control over grain size, distribution of grain sizes, thickness of the layer across a substrate, improved carrier mobility, threshold voltage stability, or any combination thereof.
    Type: Grant
    Filed: December 22, 2004
    Date of Patent: August 15, 2006
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Rama I. Hegde, Alexander A. Demkov, Philip J. Tobin, Dina H. Triyoso
  • Publication number: 20060131671
    Abstract: A mixture of materials can be used within a layer of an electronic device to improve electrical and physical properties of the layer. In one set of embodiments, the layer can be a dielectric layer, such as a gate dielectric layer or a capacitor dielectric layer. The dielectric layer can include O, and two or more dissimilar metallic elements. In one specific embodiment, two dissimilar elements may have the same single oxidation state and be miscible within each other. In one embodiment, the dielectric layer can include an alloy of (HfO2)(1-x)(ZrO2)x, wherein x is between 0 and 1. Each of Hf and Zr has a single oxidation state of +4. Other combinations are possible. Improved electrical and physical properties can include better control over grain size, distribution of grain sizes, thickness of the layer across a substrate, improved carrier mobility, threshold voltage stability, or any combination thereof.
    Type: Application
    Filed: December 22, 2004
    Publication date: June 22, 2006
    Inventors: Rama Hegde, Alexander Demkov, Philip Tobin, Dina Triyoso
  • Publication number: 20060094249
    Abstract: A method for forming a semiconductor structure including providing a semiconductor substrate, forming a metallic buffer layer over the semiconductor substrate, forming an amorphous semiconductor layer over the metallic buffer layer, and recrystallizing the amorphous semiconductor layer to form a crystalline semiconductor layer. A semiconductor structure includes a semiconductor substrate, a buffer layer comprising at least one of silicide and germanide formed over the semiconductor substrate, and a crystalline semiconductor layer formed over the metallic buffer layer.
    Type: Application
    Filed: October 29, 2004
    Publication date: May 4, 2006
    Inventors: Alexander Demkov, William Taylor
  • Publication number: 20060060928
    Abstract: A semiconductor device (10) having a gate (16, 18 or 16, 18, 26, 28) with a thin conductive layer (18) is described. As the physical dimensions of semiconductor devices are scaled below the sub-micron regime, very thin gate dielectrics (16) are used. One problem encountered with very thin gate dielectrics is that the carriers can tunnel through the gate dielectric material, thus increasing the undesirable leakage current in the device. By using a thin layer for conductive layer (18), quantum confinement of carriers within conductive layer (18) can be induced. This quantum confinement removes modes which are propagating in the direction normal to the interfacial plane 15 from the Fermi level. Thus, the undesirable leakage current in the device (10) can be reduced. Additional conductive layers (e.g. 28) may be used to provide more carriers.
    Type: Application
    Filed: September 17, 2004
    Publication date: March 23, 2006
    Inventors: Sinan Goktepeli, Alexander Demkov, Marius Orlowski
  • Patent number: 6791125
    Abstract: A semiconductor device includes a continuous doped substrate with a surface, a sulfur-based dielectric material layer positioned on the surface of the continuous doped substrate, a dielectric material layer positioned on the sulfur-based dielectric material layer, and a gate contact region positioned on the sulfur-based dielectric material layer. The continuous doped substrate includes silicon (Si) and the sulfur-based dielectric material includes a transition metal sulfide such as strontium zirconium sulfur (SrZrS), barium zirconium sulfur (BaZrS), strontium hafnium sulfur (SrHfS), barium hafnium sulfur (BaHfS), or the like. Further, the gate contact region includes a layer of one of strontium titanium sulfur (SrTiS), barium titanium sulfur (BaTiS), or the like positioned adjacent to the dielectric material layer.
    Type: Grant
    Filed: September 30, 2002
    Date of Patent: September 14, 2004
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Alexander A. Demkov, Kurt W. Eisenbeiser
  • Publication number: 20040164315
    Abstract: Tunneling piezoelectric switch structures including high quality epitaxial layers of monocrystalline materials (26) grown overlying monocrystalline substrates (22) such as large silicon wafers are disclosed. The structures includes an accommodating buffer layer (24) spaced apart from a silicon wafer by an amorphous interface layer (28) of silicon oxide. The amorphous interface layer dissipates strain and permits the growth of a high quality monocrystalline oxide accommodating buffer layer.
    Type: Application
    Filed: February 25, 2003
    Publication date: August 26, 2004
    Applicant: MOTOROLA, INC.
    Inventor: Alexander A. Demkov
  • Publication number: 20040061188
    Abstract: A semiconductor device includes a continuous doped substrate with a surface, a sulfur-based dielectric material layer positioned on the surface of the continuous doped substrate, a dielectric material layer positioned on the sulfur-based dielectric material layer, and a gate contact region positioned on the sulfur-based dielectric material layer. The continuous doped substrate includes silicon (Si) and the sulfur-based dielectric material includes a transition metal sulfide such as strontium zirconium sulfur (SrZrS), barium zirconium sulfur (BaZrS), strontium hafnium sulfur (SrHfS), barium hafnium sulfur (BaHfS), or the like. Further, the gate contact region includes a layer of one of strontium titanium sulfur (SrTiS), barium titanium sulfur (BaTiS), or the like positioned adjacent to the dielectric material layer.
    Type: Application
    Filed: September 30, 2002
    Publication date: April 1, 2004
    Inventors: Alexander A. Demkov, Kurt W. Eisenbeiser