Patents by Inventor Fengyan Zhang

Fengyan Zhang 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: 6998661
    Abstract: A method of forming an electrode and a ferroelectric thin film thereon, includes preparing a substrate; depositing an electrode on the substrate, wherein the electrode is formed of a material taken from the group of materials consisting of iridium and iridium composites; and forming a single-phase, c-axis PGO ferroelectric thin film thereon, wherein the ferroelectric thin film exhibits surface smoothness and uniform thickness. An integrated circuit includes a substrate; an electrode deposited on the substrate, wherein the electrode is formed of a material taken from the group of materials consisting of iridium and iridium composites, wherein the iridium composites are taken from the group of composites consisting of IrO2, Ir—Ta—O, Ir—Ti—O, Ir—Nb—O, Ir—Al—O, Ir—Hf—O, Ir—V—O, Ir—Zr—O and Ir—O; and a single-phase, c-axis PGO ferroelectric thin film formed on the electrode, wherein the ferroelectric thin film exhibits surface smoothness and uniform thickness.
    Type: Grant
    Filed: March 10, 2003
    Date of Patent: February 14, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Fengyan Zhang, Jer-Shen Maa, Wei-Wei Zhuang, Sheng Teng Hsu
  • Patent number: 6991942
    Abstract: An MFIS memory array having a plurality of MFIS memory transistors with a word line connecting a plurality of MFIS memory transistor gates, wherein all MFIS memory transistors connected to a common word line have a common source, each transistor drain serves as a bit output, and all MFIS channels along a word line are separated by a P+ region and are further joined to a P+ substrate region on an SOI substrate by a P+ region is provided. Also provided are methods of making an MFIS memory array on an SOI substrate; methods of performing a block erase of one or more word lines, and methods of selectively programming a bit.
    Type: Grant
    Filed: September 28, 2004
    Date of Patent: January 31, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Fengyan Zhang, Tingkai Li
  • Publication number: 20060011897
    Abstract: A memory cell and method for controlling the resistance properties in a memory material are provided. The method comprises: forming manganite; annealing the manganite in an oxygen atmosphere; controlling the oxygen content in the manganite in response to the annealing; and, controlling resistance through the manganite in response to the oxygen content. The manganite is perovskite-type manganese oxides with the general formula RE1-xAExMnOy, where RE is a rare earth ion and AE is an alkaline-earth ion, with x in the range between 0.1 and 0.5. Controlling the oxygen content in the manganite includes forming an oxygen-rich RE1-xAExMnOy region where y is greater than 3. A low resistance results in the oxygen-rich manganite region. When y is less than 3, a high resistance is formed. More specifically, the process forms a low resistance oxygen-rich manganite region adjacent an oxygen-deficient high resistance manganite region.
    Type: Application
    Filed: September 14, 2005
    Publication date: January 19, 2006
    Inventors: Sheng Hsu, Fengyan Zhang
  • Publication number: 20060003489
    Abstract: A one-mask etching method for use with a PCMO-containing RRAM to reduce stack side-wall residuals, includes preparing a substrate, taken from the group of substrates consisting of silicon, silicon dioxide and polysilicon; depositing a bottom electrode on the substrate; depositing a PCMO layer on the bottom electrode; depositing a top electrode on the PCMO layer; depositing a hard mask on the top electrode; depositing and patterning a photoresist layer on the hard mask; etching the hard mask; etching the top electrode using a first etching process having an etching atmosphere consisting of Ar, O2, and Cl2; etching the PCMO layer using an etching process taken from the group of etching processes consisting of the first etching process and a second etching process having an etching atmosphere consisting of Ar and O2. etching the bottom electrode using the first etching process; and completing the RRAM device.
    Type: Application
    Filed: July 1, 2004
    Publication date: January 5, 2006
    Inventors: Fengyan Zhang, Lisa Stecker, Bruce Ulrich, Sheng Hsu
  • Patent number: 6972238
    Abstract: A memory cell and method for controlling the resistance properties in a memory material are provided. The method comprises: forming manganite; annealing the manganite in an oxygen atmosphere; controlling the oxygen content in the manganite in response to the annealing; and, controlling resistance through the manganite in response to the oxygen content. The manganite is perovskite-type manganese oxides with the general formula RE1-xAExMnOy, where RE is a rare earth ion and AE is an alkaline-earth ion, with x in the range between 0.1 and 0.5. Controlling the oxygen content in the manganite includes forming an oxygen-rich RE1-xAExMnOy region where y is greater than 3. A low resistance results in the oxygen-rich manganite region. When y is less than 3, a high resistance is formed. More specifically, the process forms a low resistance oxygen-rich manganite region adjacent an oxygen-deficient high resistance manganite region.
    Type: Grant
    Filed: May 21, 2003
    Date of Patent: December 6, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Fengyan Zhang
  • Publication number: 20050243630
    Abstract: An asymmetric-area memory cell, and a fabrication method for forming an asymmetric-area memory cell, are provided. The method comprises: forming a bottom electrode having an area; forming a CMR memory film overlying the bottom electrode, having an asymmetric area; and, forming a top electrode having an area, less than the bottom electrode area, overlying the CMR film. In one aspect, the CMR film has a first area adjacent the top electrode and a second area, greater than the first area, adjacent the bottom electrode. Typically, the CMR film first area is approximately equal to the top electrode area, although the CMR film second area may be less than the bottom electrode area.
    Type: Application
    Filed: July 1, 2005
    Publication date: November 3, 2005
    Inventors: Sheng Hsu, Fengyan Zhang
  • Publication number: 20050239262
    Abstract: A method is provided for forming a Pr0.3Ca0.7MnO3 (PCMO) thin film with crystalline structure-related memory resistance properties. The method comprises: forming a PCMO thin film with a first crystalline structure; and, changing the resistance state of the PCMO film using pulse polarities responsive to the first crystalline structure. In one aspect the first crystalline structure is either amorphous or a weak-crystalline. Then, the resistance state of the PCMO film is changed in response to unipolar pulses. In another aspect, the PCMO thin film has either a polycrystalline structure. Then, the resistance state of the PCMO film changes in response to bipolar pulses.
    Type: Application
    Filed: April 23, 2004
    Publication date: October 27, 2005
    Inventors: Wei-Wei Zhuang, Tingkai Li, Sheng Hsu, Fengyan Zhang
  • Patent number: 6955992
    Abstract: A method of dry etching a PCMO stack, includes preparing a substrate; depositing a barrier layer; depositing a bottom electrode; depositing a PCMO thin film; depositing a top electrode; depositing a hard mask layer; applying photoresist and patterning; etching the hard mask layer; dry etching the top electrode; dry etching the PCMO layer in a multi-step etching process; dry etching the bottom electrode; and completing the PCMO-based device.
    Type: Grant
    Filed: September 30, 2003
    Date of Patent: October 18, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Fengyan Zhang, Sheng Teng Hsu
  • Patent number: 6949435
    Abstract: An asymmetric-area memory cell, and a fabrication method for forming an asymmetric-area memory cell, are provided. The method includes: forming a bottom electrode having an area; forming a CMR memory film overlying the bottom electrode, having an asymmetric area; and, forming a top electrode having an area, less than the bottom electrode area, overlying the CMR film. In one aspect, the CMR film has a first area adjacent the top electrode and a second area, greater than the first area, adjacent the bottom electrode. Typically, the CMR film first area is approximately equal to the top electrode area, although the CMR film second area may be less than the bottom electrode area.
    Type: Grant
    Filed: December 8, 2003
    Date of Patent: September 27, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Fengyan Zhang
  • Publication number: 20050199935
    Abstract: A method is provided for forming a single-phase c-axis PGO film overlying a Pt metal electrode. Although the method is summarized in the context of a Pt bottom electrode, it has a broader application to other noble metals. The method comprises: forming a bottom electrode mixture of Pt and Pt3O4; forming a single-phase c-axis PGO thin film overlying the bottom electrode; and, forming a top electrode overlying the PGO thin film. Forming a bottom electrode mixture of a Pt and Pt3O4 includes: forming a Pt first layer; and, forming a second layer, interposed between the first layer and the PGO thin film, of fully oxidized Pt3O4. In other aspects, forming a bottom electrode mixture of Pt and Pt3O4 includes forming a polycrystalline mixture of Pt and Pt3O4. A c-axis PGO film capacitor is also provided. Again, a Pt bottom electrode is described, along with other noble metal bottom electrodes.
    Type: Application
    Filed: March 15, 2004
    Publication date: September 15, 2005
    Inventors: Fengyan Zhang, Sheng Hsu
  • Publication number: 20050196878
    Abstract: A method for forming a doped PGO ferroelectric thin film, and related doped PGO thin film structures are described. The method comprising: forming either an electrically conductive or electrically insulating substrate; forming a doped PGO film overlying the substrate; annealing; crystallizing; and, forming a single-phase c-axis doped PGO thin film overlying the substrate, having a Curie temperature of greater than 200 degrees C. Forming a doped PGO film overlying the substrate includes depositing a doped precursor in the range between 0.1N and 0.5N, with a molecular formula of Pby?xMxGe3O11, where: M is a doping element; y=4.5 to 6; and, x=0.1 to 1. The element M can be Sn, Ba, Sr, Cd, Ca, Pr, Ho, La, Sb, Zr, or Sm.
    Type: Application
    Filed: January 28, 2005
    Publication date: September 8, 2005
    Inventors: Fengyan Zhang, Wei-Wei Zhuang, Jong-Jan Lee, Sheng Hsu
  • Patent number: 6921671
    Abstract: A method of fabricating a ferroelectric thin film on an iridium-composite electrode in an integrated circuit device includes preparing a substrate; depositing an iridium-composite bottom electrode on the substrate; annealing the bottom electrode in a first annealing step; depositing a buffer layer on the bottom electrode, including depositing a layer of material taken from the group of materials consisting of HfO2, ZrO2, TiO2, LaOx, La—Al—O, Ti—Al—O, Hf—Al—O, Zr—Al—O, Hf—Zr—O, Zr—Ti—O, Hf—Ti—O, La—Zr—O, La—Hf—O, and La—Ti—O; annealing the buffer layer in a second annealing step; depositing a layer of Bi4Ti3O12, to a thickness of between about 20 nm to 500 nm, on the buffer layer; annealing the ferroelectric layer in a third annealing step; and completing the integrated circuit device.
    Type: Grant
    Filed: February 23, 2004
    Date of Patent: July 26, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Fengyan Zhang, Wei-Wei Zhuang, Sheng Teng Hsu
  • Patent number: 6911361
    Abstract: A method of applying a PCMO thin film on an iridium substrate for use in a RRAM device, includes preparing a substrate; depositing a barrier layer on the substrate; depositing a layer of iridium on the barrier layer; spin coating a layer of PCMO on the iridium; baking the PCMO and substrate in a three-step baking process; post-bake annealing the substrate and the PCMO in a RTP chamber; repeating said spin coating, baking and annealing steps until the PCMO has a desired thickness; annealing the substrate and PCMO; depositing a top electrode; and completing the RRAM device.
    Type: Grant
    Filed: March 10, 2003
    Date of Patent: June 28, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Fengyan Zhang, Wei-Wei Zhuang, Wei Pan, Sheng Teng Hsu
  • Patent number: 6906366
    Abstract: A ferroelectric transistor gate structure with a ferroelectric gate and a high-k insulator is provided. The high-k insulator may serve as both a gate dielectric and an insulator to reduce, or eliminate, the diffusion of oxygen or hydrogen into the ferroelectric gate. A method of forming the ferroelectric gate structure is also provided. The method comprises the steps of forming a sacrificial gate structure, removing the sacrificial gate structure, depositing a high-k insulator, depositing a ferroelectric material, polishing the ferroelectric material using CMP, and forming a top electrode overlying the ferroelectric material.
    Type: Grant
    Filed: May 20, 2003
    Date of Patent: June 14, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Fengyan Zhang
  • Publication number: 20050124112
    Abstract: An asymmetric-area memory cell, and a fabrication method for forming an asymmetric-area memory cell, are provided. The method comprises: forming a bottom electrode having an area; forming a CMR memory film overlying the bottom electrode, having an asymmetric area; and, forming a top electrode having an area, less than the bottom electrode area, overlying the CMR film. In one aspect, the CMR film has a first area adjacent the top electrode and a second area, greater than the first area, adjacent the bottom electrode. Typically, the CMR film first area is approximately equal to the top electrode area, although the CMR film second area may be less than the bottom electrode area.
    Type: Application
    Filed: December 8, 2003
    Publication date: June 9, 2005
    Inventors: Sheng Hsu, Fengyan Zhang
  • Patent number: 6897074
    Abstract: A method for forming a doped PGO ferroelectric thin film, and related doped PGO thin film structures are described. The method comprising: forming either an electrically conductive or electrically insulating substrate; forming a doped PGO film overlying the substrate; annealing; crystallizing; and, forming a single-phase c-axis doped PGO thin film overlying the substrate, having a Curie temperature of greater than 200 degrees C. Forming a doped PGO film overlying the substrate includes depositing a doped precursor in the range between 0.1N and 0.5N, with a molecular formula of Pby-xMxGe3O11, where: M is a doping element; y=4.5 to 6; and, x=0.1 to 1. The element M can be Sn, Ba, Sr, Cd, Ca, Pr, Ho, La, Sb, Zr, or Sm.
    Type: Grant
    Filed: March 3, 2004
    Date of Patent: May 24, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Fengyan Zhang, Wei-Wei Zhuang, Jong-Jan Lee, Sheng Teng Hsu
  • Publication number: 20050079727
    Abstract: A method of dry etching a PCMO stack, includes preparing a substrate; depositing a barrier layer; depositing a bottom electrode; depositing a PCMO thin film; depositing a top electrode; depositing a hard mask layer; applying photoresist and patterning; etching the hard mask layer; dry etching the top electrode; dry etching the PCMO layer in a multi-step etching process; dry etching the bottom electrode; and completing the PCMO-based device.
    Type: Application
    Filed: September 30, 2003
    Publication date: April 14, 2005
    Inventors: Fengyan Zhang, Sheng Hsu
  • 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
  • Patent number: 6849564
    Abstract: A low-capacitance one-resistor/one-diode (1R1D) R-RAM array with a floating p-well is provided. The fabrication method comprises: forming an integrated circuit (IC) substrate; forming an n-doped buried layer (buried n layer) of silicon overlying the substrate; forming n-doped silicon sidewalls overlying the buried n layer; forming a p-doped well of silicon (p-well) overlying the buried n layer; and, forming a 1R1D R-RAM array overlying the p-well. Typically, the combination of the buried n layer and the n-doped sidewalls form an n-doped well (n-well) of silicon. Then, the p-well is formed inside the n-well. In other aspects, the p-well has sidewalls, and the method further comprises: forming an oxide insulator overlying the p-well sidewalls, between the n-well and the R-RAM array.
    Type: Grant
    Filed: February 27, 2003
    Date of Patent: February 1, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Wei Pan, Wei-Wei Zhuang, Fengyan Zhang
  • 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