Patents by Inventor Tingkai Li

Tingkai Li 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: 20050151210
    Abstract: The present invention discloses a novel ferroelectric transistor design using a resistive oxide film in place of the gate dielectric. By replacing the gate dielectric with a resistive oxide film, and by optimizing the value of the film resistance, the bottom gate of the ferroelectric layer is electrically connected to the silicon substrate, eliminating the trapped charge effect and resulting in the improvement of the memory retention characteristics. The resistive oxide film is preferably a doped conductive oxide in which a conductive oxide is doped with an impurity species. The doped conductive oxide is most preferred to be In2O3 with the dopant species being hafnium oxide, zirconium oxide, lanthanum oxide, or aluminum oxide.
    Type: Application
    Filed: January 12, 2004
    Publication date: July 14, 2005
    Inventors: Tingkai Li, Sheng Hsu
  • Publication number: 20050136637
    Abstract: One-transistor ferroelectric memory devices using an indium oxide film (In2O3), an In2O3 film structure, and corresponding fabrication methods have been provided. The method for controlling resistivity in an In2O3 film comprises: depositing an In film using a PVD process, typically with a power in the range of 200 to 300 watts; forming a film including In overlying a substrate material; simultaneously (with the formation of the In-including film) heating the substrate material, typically the substrate is heated to a temperature in the range of 20 to 200 degrees C.; following the formation of the In-including film, post-annealing, typically in an O2 atmosphere; and, in response to the post-annealing: forming an In2O3 film; and, controlling the resistivity in the In2O3 film. For example, the resistivity can be controlled in the range of 260 to 800 ohm-cm.
    Type: Application
    Filed: January 19, 2005
    Publication date: June 23, 2005
    Inventors: Tingkai Li, Sheng Hsu
  • Patent number: 6887799
    Abstract: One-transistor ferroelectric memory devices using an indium oxide film (In2O3), an In2O3 film structure, and corresponding fabrication methods have been provided. The method for controlling resistivity in an In2O3 film comprises: depositing an In film using a PVD process, typically with a power in the range of 200 to 300 watts; forming a film including In overlying a substrate material; simultaneously (with the formation of the In-including film) heating the substrate material, typically the substrate is heated to a temperature in the range of 20 to 200 degrees C.; following the formation of the In-including film, post-annealing, typically in an O2 atmosphere; and, in response to the post-annealing: forming an In2O3 film; and, controlling the resistivity in the In2O3 film. For example, the resistivity can be controlled in the range of 260 to 800 ohm-cm.
    Type: Grant
    Filed: December 18, 2003
    Date of Patent: May 3, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu
  • Publication number: 20050070114
    Abstract: A method of selective etching a metal oxide layer for fabrication of a ferroelectric device includes preparing a silicon substrate, including forming an oxide layer thereon; depositing a layer of metal or metal oxide thin film on the substrate; patterning and selectively etching the metal or metal oxide thin film without substantially over etching into the underlying oxide layer; depositing a layer of ferroelectric material; depositing a top electrode on the ferroelectric material; and completing the ferroelectric device.
    Type: Application
    Filed: September 30, 2003
    Publication date: March 31, 2005
    Inventors: Tingkai Li, Sheng Hsu, Bruce Ulrich
  • Publication number: 20050069643
    Abstract: A method of selectively depositing a ferroelectric thin film on an indium-containing substrate in a ferroelectric device includes preparing a silicon substrate; depositing an indium-containing thin film on the substrate; patterning the indium containing thin film; annealing the structure; selectively depositing a ferroelectric layer by MOCVD; annealing the structure; and completing the ferroelectric device.
    Type: Application
    Filed: September 30, 2003
    Publication date: March 31, 2005
    Inventors: Tingkai Li, Sheng Hsu, Bruce Ulrich
  • Publication number: 20050054119
    Abstract: A method is provided for forming a buffered-layer memory cell. The method comprises: forming a bottom electrode; forming a colossal magnetoresistance (CMR) memory film overlying the bottom electrode; forming a memory-stable semiconductor buffer layer, typically a metal oxide, overlying the memory film; and, forming a top electrode overlying the semiconductor buffer layer. In some aspects of the method the semiconductor buffer layer is formed from YBa2Cu3O7?X (YBCO), indium oxide (In2O3), or ruthenium oxide (RuO2), having a thickness in the range of 10 to 200 nanometers (nm). The top and bottom electrodes may be TiN/Ti, Pt/TiN/Ti, In/TiN/Ti, PtRhOx compounds, or PtIrOx compounds. The CMR memory film may be a Pr1?XCaXMnO3 (PCMO) memory film, where x is in the region between 0.1 and 0.6, with a thickness in the range of 10 to 200 nm.
    Type: Application
    Filed: January 12, 2004
    Publication date: March 10, 2005
    Inventors: Sheng Hsu, Tingkai Li, Fengyan Zhang, Wei Pan, Wei-Wei Zhuang, David Evans, Masayuki Tajiri
  • Publication number: 20050054166
    Abstract: The present invention discloses a ferroelectric transistor having a conductive oxide in the place of the gate dielectric. The conductive oxide gate ferroelectric transistor can have a three-layer metal/ferroelectric/metal or a two-layer metal/ferroelectric on top of the conductive oxide gate. By replacing the gate dielectric with a conductive oxide, the bottom gate of the ferroelectric layer is conductive through the conductive oxide to the silicon substrate, thus minimizing the floating gate effect. The memory retention degradation related to the leakage current associated with the charges trapped within the floating gate is eliminated. The fabrication of the ferroelectric transistor by a gate etching process or a replacement gate process is also disclosed.
    Type: Application
    Filed: September 9, 2003
    Publication date: March 10, 2005
    Inventors: Sheng Hsu, Tingkai Li
  • Publication number: 20050037520
    Abstract: A method for obtaining reversible resistance switches on a PCMO thin film when integrated with a highly crystallized seed layer includes depositing, by MOCVD, a seed layer of PCMO, in highly crystalline form, thin film, having a thickness of between about 50 ? to 300 ?, depositing a second PCMO thin film layer on the seed layer, by spin coating, having a thickness of between about 500 ? to 3000 ?, to form a combined PCMO layer; increasing the resistance of the combined PCMO film in a semiconductor device by applying a negative electric pulse of between about ?4V to ?5V, having a pulse width of between about 75 nsec to 1 ?sec; and decreasing the resistance of the combined PCMO layer in a semiconductor device by applying a positive electric pulse of between about +2.5V to +4V, having a pulse width greater than 2.0 ?sec.
    Type: Application
    Filed: August 13, 2003
    Publication date: February 17, 2005
    Inventors: Wei-Wei Zhuang, Tingkai Li, David Evans, Sheng Hsu, Wei Pan
  • Patent number: 6849891
    Abstract: A RRAM memory cell is formed on a silicon substrate having a operative junction therein and a metal plug formed thereon, includes a first oxidation resistive layer; a first refractory metal layer; a CMR layer; a second refractory metal layer; and a second oxidation resistive layer. A method of fabricating a multi-layer electrode RRAM memory cell includes preparing a silicon substrate; forming a junction in the substrate taken from the group of junctions consisting of N+ junctions and P+ junctions; depositing a metal plug on the junction; depositing a first oxidation resistant layer on the metal plug; depositing a first refractory metal layer on the first oxidation resistant layer; depositing a CMR layer on the first refractory metal layer; depositing a second refractory metal layer on the CMR layer; depositing a second oxidation resistant layer on the second refractory metal layer; and completing the RRAM memory cell.
    Type: Grant
    Filed: December 8, 2003
    Date of Patent: February 1, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Wei Pan, Fengyan Zhang, Wei-Wei Zhuang, Tingkai Li
  • Patent number: 6849467
    Abstract: A method of forming an H2 passivation layer in an FeRAM includes preparing a silicon substrate; depositing a layer of TiOx thin film, where 0<x<2, on a damascene structure; plasma space etching of the Ti or TiOx thin film to form a TiOx sidewall; annealing the TiOx side wall thin film form a TiO2 thin film; depositing a layer of ferroelectric material; and metallizing the structure to form a FeRAM.
    Type: Grant
    Filed: July 16, 2003
    Date of Patent: February 1, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Wei Pan, Robert A. Barrowcliff, David R. Evans, Sheng Teng Hsu
  • Publication number: 20050014296
    Abstract: A method of forming an H2 passivation layer in an FeRAM includes preparing a silicon substrate; depositing a layer of TiOx thin film, where 0<x<2, on a damascene structure; plasma space etching of the Ti or TiOx thin film to form a TiOx sidewall; annealing the TiOx side wall thin film to form a TiO2 thin film; depositing a layer of ferroelectric material; and metallizing the structure to form a FeRAM.
    Type: Application
    Filed: July 16, 2003
    Publication date: January 20, 2005
    Inventors: Tingkai Li, Wei Pan, Robert Barrowcliff, David Evans, Sheng Hsu
  • Patent number: 6833572
    Abstract: An electrode for use in a ferroelectric device includes a bottom electrode; a ferroelectric layer; and a top electrode formed on the ferroelectric layer and formed of a combination of metals, including a first metal take from the group of metals consisting of platinum and iridium, and a second metal taken from the group of metals consisting of aluminum and titanium; wherein the top electrode acts as a passivation layer and wherein the top electrode remains conductive following high temperature annealing in a hydrogen atmosphere.
    Type: Grant
    Filed: August 27, 2002
    Date of Patent: December 21, 2004
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Fengyan Zhang, Tingkai Li, Hong Ying, Yoshi Ono, Sheng Teng Hsu
  • Patent number: 6825519
    Abstract: A memory device formed from selectively deposited PGO and a method for selectively forming a Pb5Ge3O11 (PGO) thin film memory device are provided. The method comprises: forming a silicon (Si) substrate; forming a silicon oxide film overlying the substrate; forming a patterned bottom electrode overlying the silicon oxide film; selectively depositing a PGO film overlying the bottom electrode; annealing; and, forming a top electrode overlying the PGO film. Selectively depositing a PGO film overlying the bottom electrodes includes: depositing a seed layer of PGO; and, forming a c-axis oriented PGO layer overlying the seed layer.
    Type: Grant
    Filed: March 27, 2003
    Date of Patent: November 30, 2004
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu, Bruce D. Ulrich
  • Publication number: 20040233708
    Abstract: An asymmetric memory cell and method for forming an asymmetric memory cell are provided. The method comprises: forming a bottom electrode having a first area; forming an electrical pulse various resistance (EPVR) material overlying the bottom electrode; forming a top electrode overlying the EPVR layer having a second area, less than the first area. In some aspects the second area is at least 20% smaller than the first area. The EPVR is a material such as colossal magnetoresistance (CMR), high temperature super conducting (HTSC), or perovskite metal oxide materials. The method further comprises: inducing an electric field between the electrodes; inducing current flow through the EPVR adjacent the top electrode; and, in response to inducing current flow through the EPVR adjacent the top electrode, modifying the resistance of the EPVR. Typically, the resistance is modified within the range of 100 ohms to 10 mega-ohms.
    Type: Application
    Filed: May 21, 2003
    Publication date: November 25, 2004
    Applicant: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Tingkai Li, David R. Evans
  • Patent number: 6819583
    Abstract: A ferroelectric thin film resistor memory array is formed on a substrate and includes plural memory cells arranged in an array of rows and columns; wherein each memory cell includes: a FE resistor having a pair of terminals, and a transistor associated with each resistor, wherein each transistor has a gate, a drain and a source, and wherein the drain of each transistor is electrically connected to one terminal of its associated resistor; a word line connected to the gate of each transistor in a row; a programming line connected to each memory cell in a column; and a bit line connected to each memory cell in a column.
    Type: Grant
    Filed: January 15, 2003
    Date of Patent: November 16, 2004
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Tingkai Li, Fengyan Zhang
  • Publication number: 20040188743
    Abstract: A memory device formed from selectively deposited PGO and a method for selectively forming a Pb5Ge3O11 (PGO) thin film memory device are provided. The method comprises: forming a silicon (Si) substrate; forming a silicon oxide film overlying the substrate; forming a patterned bottom electrode overlying the silicon oxide film; selectively depositing a PGO film overlying the bottom electrode; annealing; and, forming a top electrode overlying the PGO film. Selectively depositing a PGO film overlying the bottom electrode includes: depositing a seed layer of PGO; and, forming a c-axis oriented PGO layer overlying the seed layer.
    Type: Application
    Filed: March 27, 2003
    Publication date: September 30, 2004
    Applicant: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu, Bruce D. Ulrich
  • Publication number: 20040185669
    Abstract: A method of etching includes preparing a substrate; depositing a first etch stop layer; forming an iridium bottom electrode layer; depositing a SiN layer; depositing and patterning an aluminum hard mask; etching a non-patterned SiN layer with a SiN selective etchant, stopping at the level of the iridium bottom electrode layer; etching the first etch stop layer with a second selective etchant; depositing an oxide layer and CMP the oxide layer to the level of the remaining SiN layer; wet etching the SiN layer to form a trench; depositing a layer of ferroelectric material in the trench formed by removal of the SiN layer; depositing a layer of high-k oxide; and completing the device, including metallization.
    Type: Application
    Filed: March 17, 2003
    Publication date: September 23, 2004
    Applicant: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Bruce D. Ulrich, David R. Evans, Sheng Teng Hsu
  • Patent number: 6794198
    Abstract: A method of forming a PGO thin film on a high-k dielectric includes preparing a silicon substrate, including forming a high-k gate oxide layer thereon; patterning the high-k gate oxide; annealing the substrate in a first annealing step; placing the substrate in a MOCVD chamber; depositing a PGO thin film by injecting a PGO precursor into the MOCVD chamber; and annealing the structure having a PGO thin film on a high-k gate oxide in a second annealing step.
    Type: Grant
    Filed: June 25, 2003
    Date of Patent: September 21, 2004
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu, David R. Evans, Bruce D. Ulrich
  • Publication number: 20040170761
    Abstract: A single solution MOCVD precursor is provided for depositing PCMO. An MOCVD process is provided for controlling the composition of PCMO by determining the deposition rate of each metal component within the precursor solution and determining the molar ratio of the metals based on the deposition rates of each within the temperature ranges for substrate temperature and vaporizer temperature, and the composition of PCMO to be deposited. The composition of the PCMO is further controlled by adjusting the substrate temperature, the vaporizer temperature or both.
    Type: Application
    Filed: February 27, 2003
    Publication date: September 2, 2004
    Applicant: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Wei-Wei Zhuang, Lawrence J. Charneski, David R. Evans, Sheng Teng Hsu
  • Publication number: 20040136223
    Abstract: A ferroelectric thin film resistor memory array is formed on a substrate and includes plural memory cells arranged in an array of rows and columns; wherein each memory cell includes: a FE resistor having a pair of terminals, and a transistor associated with each resistor, wherein each transistor has a gate, a drain and a source, and wherein the drain of each transistor is electrically connected to one terminal of its associated resistor; a word line connected to the gate of each transistor in a row; a programming line connected to each memory cell in a column; and a bit line connected to each memory cell in a column.
    Type: Application
    Filed: January 15, 2003
    Publication date: July 15, 2004
    Applicant: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Tingkai Li, Fengyan Zhang