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: 20060068509
    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: Application
    Filed: October 28, 2005
    Publication date: March 30, 2006
    Inventors: Sheng Hsu, Fengyan Zhang, Tingkai Li
  • Patent number: 7008801
    Abstract: A method of forming a ferroelectric thin film on a high-k layer includes preparing a silicon substrate; forming a high-k layer on the substrate; depositing a seed layer of ferroelectric material at a relatively high temperature on the high-k layer; depositing a top layer of ferroelectric material on the seed layer at a relatively low temperature; and annealing the substrate, the high-k layer and the ferroelectric layers to form a ferroelectric thin film.
    Type: Grant
    Filed: June 2, 2003
    Date of Patent: March 7, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu
  • Patent number: 7008833
    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: Grant
    Filed: January 12, 2004
    Date of Patent: March 7, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu
  • Publication number: 20060038242
    Abstract: The present invention discloses a novel transistor structure employing semiconductive metal oxide as the transistor conductive channel. By replacing the silicon conductive channel with a semiconductive metal oxide channel, the transistors can achieve simpler fabrication process and could realize 3D structure to increase circuit density. The disclosed semiconductive metal oxide transistor can have great potential in ferroelectric non volatile memory device with the further advantages of good interfacial properties with the ferroelectric materials, possible lattice matching with the ferroelectric layer, reducing or eliminating the oxygen diffusion problem to improve the reliability of the ferroelectric memory transistor. The semiconductive metal oxide film is preferably a metal oxide exhibiting semiconducting properties at the transistor operating conditions, for example, In2O3 or RuO2.
    Type: Application
    Filed: August 20, 2004
    Publication date: February 23, 2006
    Inventors: Sheng Hsu, Tingkai Li, Jong-Jan Lee
  • Publication number: 20060035390
    Abstract: A method of forming a ferroelectric thin film on a high-k layer includes preparing a silicon substrate; forming a high-k layer on the substrate; depositing a seed layer of ferroelectric material at a relatively high temperature on the high-k layer; depositing a top layer of ferroelectric material on the seed layer at a relatively low temperature; and annealing the substrate, the high-k layer and the ferroelectric layers to form a ferroelectric thin film.
    Type: Application
    Filed: October 12, 2005
    Publication date: February 16, 2006
    Inventors: Tingkai Li, Sheng Hsu
  • Patent number: 6995025
    Abstract: A method of fabricating and programming a ferroelectric memory transistor for asymmetrical programming includes fabricating a ferroelectric memory transistor having a metal oxide layer overlaying a gate region; and programming the ferroelectric memory transistor so that a low threshold voltage is about equal to the intrinsic threshold voltage of the ferrorelectric memory transistor.
    Type: Grant
    Filed: June 21, 2004
    Date of Patent: February 7, 2006
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Tingkai Li
  • 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: 20050282296
    Abstract: A method of fabricating and programming a ferroelectric memory transistor for asymmetrical programming includes fabricating a ferroelectric memory transistor having a metal oxide layer overlaying a gate region; and programming the ferroelectric memory transistor so that a low threshold voltage is about equal to the intrinsic threshold voltage of the ferrorelectric memory transistor.
    Type: Application
    Filed: June 21, 2004
    Publication date: December 22, 2005
    Inventors: Sheng Hsu, Tingkai Li
  • Publication number: 20050275064
    Abstract: A multi-layer PrxCa1-xMnO3 (PCMO) thin film capacitor and associated deposition method are provided for forming a bipolar switching thin film. The method comprises: forming a bottom electrode; depositing a nanocrystalline PCMO layer; depositing a polycrystalline PCMO layer; forming a multi-layer PCMO film with bipolar switching properties; and, forming top electrode overlying the PCMO film. If the polycrystalline layers are deposited overlying the nanocrystalline layers, a high resistance can be written with narrow pulse width, negative voltage pulses. The PCMO film can be reset to a low resistance using a narrow pulse width, positive amplitude pulse. Likewise, if the nanocrystalline layers are deposited overlying the polycrystalline layers, a high resistance can be written with narrow pulse width, positive voltage pulses, and reset to a low resistance using a narrow pulse width, negative amplitude pulse.
    Type: Application
    Filed: May 27, 2004
    Publication date: December 15, 2005
    Inventors: Tingkai Li, Lawrence Charneski, Wei-Wei Zhuang, David Evans, Sheng Hsu
  • Publication number: 20050269613
    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: July 18, 2005
    Publication date: December 8, 2005
    Inventors: Tingkai Li, Sheng Hsu
  • Patent number: 6972239
    Abstract: A method of fabricating a PCMO thin film at low temperature for use in a RRAM device includes preparing a PCMO precursor; preparing a substrate; placing the substrate into a MOCVD chamber; introducing the PCMO precursor into the MOCVD chamber to deposit a PCMO thin film on the substrate; maintaining a MOCVD vaporizer at between about 240° C. to 280° C. and maintaining the MOCVD chamber at a temperature of between about 300° C. to 400° C.; removing the PCMO thin-film bearing substrate from the MOCVD chamber; and completing the RRAM device.
    Type: Grant
    Filed: August 20, 2004
    Date of Patent: December 6, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Wei-Wei Zhuang, Lawrence J. Charneski, David R. Evans, Sheng Teng Hsu
  • Publication number: 20050266686
    Abstract: A method of fabricating a CMR thin film for use in a semiconductor device includes preparing a CMR precursor in the form of a metal acetate based acetic acid solution; preparing a wafer; placing a wafer in a spin-coating chamber; spin-coating and heating the wafer according to the following: injecting the CMR precursor into a spin-coating chamber and onto the surface of the wafer in the spin-coating chamber; accelerating the wafer to a spin speed of between about 1500 RPM to 3000 RPM for about 30 seconds; baking the wafer at a temperature of about 180° C. for about one minute; ramping the temperature to about 230° C.; baking the wafer for about one minute at the ramped temperature; annealing the wafer at about 500° C. for about five minutes; repeating said spin-coating and heating steps at least three times; post-annealing the wafer at between about 500° C. to 600° C. for between about one to six hours in dry, clean air; and completing the semiconductor device.
    Type: Application
    Filed: May 27, 2004
    Publication date: December 1, 2005
    Inventors: Wei-Wei Zhuang, Tingkai Li, Wei Pan, David Evans, Sheng Hsu
  • Publication number: 20050245039
    Abstract: PrCaMnO (PCMO) thin films with predetermined memory-resistance characteristics and associated formation processes have been provided. In one aspect the method comprises: forming a Pr3+1?xCa2+xMnO thin film composition, where 0.1<x<0.6; in response to the selection of x, varying the ratio of Mn and O ions as follows: O2?(3±20%); Mn3+((1?x)±20%); and, Mn4+(x±20%). When the PCMO thin film has a Pr3+0.70Ca2+0.30Mn3+0.78Mn4+0.22O2?2.96 composition, the ratio of Mn and O ions varies as follows: O2?(2.96); Mn3+((1?x)+8%); and, Mn4+(x?8%). In another aspect, the method creates a density in the PCMO film, responsive to the crystallographic orientation. For example, if the PCMO film has a (110) orientation, a density is created in the range of 5 to 6.76 Mn atoms per 100 ?2 in a plane perpendicular to the (110) orientation.
    Type: Application
    Filed: April 30, 2004
    Publication date: November 3, 2005
    Inventors: Tingkai Li, Wei-Wei Zhuang, David Evans, Sheng Hsu
  • 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: 6951825
    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: Grant
    Filed: March 17, 2003
    Date of Patent: October 4, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Bruce D. Ulrich, David R. Evans, Sheng Teng Hsu
  • Publication number: 20050207265
    Abstract: Asymmetrically structured memory cells and a fabrication method are provided. The method comprises: forming a bottom electrode; forming an electrical pulse various resistance (EPVR) first layer having a polycrystalline structure over the bottom electrode; forming an EPVR second layer adjacent the first layer, with a nano-crystalline or amorphous structure; and, forming a top electrode overlying the first and second EPVR layers. EPVR materials include CMR, high temperature super conductor (HTSC), or perovskite metal oxide materials. In one aspect, the EPVR first layer is deposited with a metalorganic spin coat (MOD) process at a temperature in the range between 550 and 700 degrees C. The EPVR second layer is formed at a temperature less than, or equal to the deposition temperature of the first layer. After a step of removing solvents, the MOD deposited EPVR second layer is formed at a temperature less than, or equal to the 550 degrees C.
    Type: Application
    Filed: May 16, 2005
    Publication date: September 22, 2005
    Inventors: Sheng Hsu, Tingkai Li, David Evans, Wei-Wei Zhuang, Wei Pan
  • Patent number: 6939724
    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: Grant
    Filed: August 13, 2003
    Date of Patent: September 6, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Wei-Wei Zhuang, Tingkai Li, David R. Evans, Sheng Teng Hsu, Wei Pan
  • Publication number: 20050178656
    Abstract: Methods of forming depositing a ferroelectric thin film, such as PGO, by preparing a substrate with an upper surface of silicon, silicon oxide, or a high-k material, such as hafnium oxide, zirconium oxide, aluminum oxide, and lanthanum oxide, depositing an indium oxide film over the substrate, and then depositing the ferroelectric film using MOCVD.
    Type: Application
    Filed: February 17, 2004
    Publication date: August 18, 2005
    Inventors: Tingkai Li, Sheng Hsu, Bruce Ulrich
  • Patent number: 6927074
    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: Grant
    Filed: May 21, 2003
    Date of Patent: August 9, 2005
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Tingkai Li, David R. Evans
  • Publication number: 20050156254
    Abstract: An ultra-shallow surface channel MOS transistor and method for fabricating the same have been provided. The method comprises: forming CMOS source and drain regions, and an intervening well region; depositing a surface channel on the surface overlying the well region; forming a high-k dielectric overlying the surface channel; and, forming a gate electrode overlying the high-k dielectric. Typically, the surface channel is a metal oxide, and may be one of the following materials: indium oxide (In2O3), ZnO, RuO, ITO, or LaX-1SrXCoO3. In some aspects, the method further comprises: depositing a placeholder material overlying the surface channel; and, etching the placeholder material to form a gate region overlying the surface channel. In one aspect, the high-k dielectric is deposited prior to the deposition of the placeholder material. Alternately, the high-k dielectric is deposited following the etching of the placeholder material.
    Type: Application
    Filed: January 21, 2004
    Publication date: July 21, 2005
    Inventors: Tingkai Li, Sheng Hsu, Bruce Ulrich