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).

  • Patent number: 7358160
    Abstract: A compound semiconductor-on-silicon (Si) wafer with a Si nanowire buffer layer is provided, along with a corresponding fabrication method. The method forms a Si substrate. An insulator layer is formed overlying the Si substrate, with Si nanowires having exposed tips. Compound semiconductor is selectively deposited on the Si nanowire tips. A lateral epitaxial overgrowth (LEO) process grows compound semiconductor from the compound semiconductor-coated Si nanowire tips, to form a compound semiconductor layer overlying the insulator. Typically, the insulator layer overlying the Si substrate is a thermally soft insulator (TSI), silicon dioxide, or SiXNY, where X?3 and Y?4. The compound semiconductor can be GaN, GaAs, GaAlN, or SiC. In one aspect, the Si nanowire tips are carbonized, and SiC is selectively deposited overlying the carbonized Si nanowire tips, prior to the selective deposition of compound semiconductor on the Si nanowire tips.
    Type: Grant
    Filed: July 6, 2006
    Date of Patent: April 15, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu
  • Patent number: 7338907
    Abstract: A dry etch process is described for selectively etching silicon nitride from conductive oxide material for use in a semiconductor fabrication process. Adding an oxidant in the etch gas mixture could increase the etch rate for the silicon nitride while reducing the etch rate for the conductive oxide, resulting in improving etch selectivity. The disclosed selective etch process is well suited for ferroelectric memory device fabrication using conductive oxide/ferroelectric interface having silicon nitride as the encapsulated material for the ferroelectric.
    Type: Grant
    Filed: October 4, 2004
    Date of Patent: March 4, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu, Bruce D. Ulrich, Mark A. Burgholzer, Ray A. Hill
  • Publication number: 20080050872
    Abstract: A method of selecting a cathode material and a resistance material for use in a RRAM includes determining the work function of a group of potential resistance materials; determining the work function of a group of potential cathode materials; and selecting a suitable material for the resistance material from the group of potential resistance materials and selecting a suitable material for the cathode material from the group of potential cathode material, wherein the work function of the cathode material is at least 0.2 eV less than the work function of the resistance material.
    Type: Application
    Filed: August 24, 2006
    Publication date: February 28, 2008
    Inventors: Sheng Teng Hsu, Tingkai Li
  • Publication number: 20080035946
    Abstract: A method is provided for forming a rare earth (RE) element-doped silicon (Si) oxide film with nanocrystalline (nc) Si particles. The method comprises: providing a first target of Si, embedded with a first rare earth element; providing a second target of Si; co-sputtering the first and second targets; forming a Si-rich Si oxide (SRSO) film on a substrate, doped with the first rare earth element; and, annealing the rare earth element-doped SRSO film. The first target is doped with a rare earth element such as erbium (Er), ytterbium (Yb), cerium (Ce), praseodymium (Pr), or terbium (Tb). The sputtering power is in the range of about 75 to 300 watts (W). Different sputtering powers are applied to the two targets. Also, deposition can be controlled by varying the effective areas of the two targets. For example, one of the targets can be partially covered.
    Type: Application
    Filed: October 9, 2007
    Publication date: February 14, 2008
    Inventors: Wei Gao, Tingkai Li, Robert Barrowcliff, Yoshi Ono, Sheng Hsu
  • Patent number: 7329548
    Abstract: A method of fabricating a conductive metal oxide gate ferroelectric memory transistor includes forming an oxide layer a substrate and removing the oxide layer in a gate area; depositing a conductive metal oxide layer on the oxide layer and on the exposed gate area; depositing a titanium layer on the metal oxide layer; patterning and etching the titanium layer and the metal oxide layer to remove the titanium layer and the metal oxide layer from the substrate except in the gate area; depositing, patterning and etching an oxide layer to form a gate trench; depositing and etching a barrier insulator layer to form a sidewall barrier in the gate trench; removing the titanium layer from the gate area; depositing, smoothing and annealing a ferroelectric layer in the gate trench; depositing, patterning and etching a top electrode; and completing the conductive metal oxide gate ferroelectric memory transistor.
    Type: Grant
    Filed: August 30, 2005
    Date of Patent: February 12, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu, Bruce D. Ulrich
  • Publication number: 20080026590
    Abstract: A method of making a doped silicon oxide thin film using a doped silicon oxide precursor solution includes mixing a silicon source in an organic acid and adding 2-methoxyethyl ether to the silicon source and organic acid to from a preliminary precursor solution. The resultant solution is heated, stirred and filtered. A doping impurity is dissolved in 2-methoxyethanol to from a doped source solution, and the resultant solution mixed with the previously described resultant solution to from a doped silicon oxide precursor solution. A doped silicon oxide thin film if formed on a wafer by spin coating. The thin film and the wafer are baked at progressively increasing temperatures and the thin film and the wafer are annealed.
    Type: Application
    Filed: July 26, 2006
    Publication date: January 31, 2008
    Inventors: Wei-Wei Zhuang, Yoshi Ono, Tingkai Li
  • Publication number: 20080026494
    Abstract: A method of fabricating an electroluminescent device includes preparing a wafer and a doped-silicon oxide precursor solution. The doped-silicon oxide precursor solution is spin coated onto the wafer to form a doped-silicon oxide thin film on the wafer, which is baked at progressively increasing temperatures. The wafer is then rapidly thermally annealed, further annealed in a wet oxygen ambient atmosphere. A transparent top electrode is deposited on the doped-silicon oxide thin film, which is patterned, etched, and annealed. The doped-silicon oxide thin film and the wafer undergo a final annealing step to enhance electroluminescent properties.
    Type: Application
    Filed: July 26, 2006
    Publication date: January 31, 2008
    Inventors: Wei-Wei Zhuang, Yoshi Ono, Wei Gao, Tingkai Li
  • Patent number: 7320897
    Abstract: A nanotip electroluminescence (EL) diode and a method are provided for fabricating said device. The method comprises: forming a plurality of Si nanotip diodes; forming a phosphor layer overlying the nanotip diode; and, forming a top electrode overlying the phosphor layer. The nanotip diodes are formed by: forming a Si substrate with a top surface; forming a Si p-well; forming an n+ layer of Si, having a thickness in the range of 30 to 300 nanometers (nm) overlying the Si p-well; forming a reactive ion etching (RIE)-induced polymer grass overlying the substrate top surface; using the RIE-induced polymer grass as a mask, etching areas of the substrate not covered by the mask; and, forming the nanotip diodes in areas of the substrate covered by the mask.
    Type: Grant
    Filed: March 23, 2005
    Date of Patent: January 22, 2008
    Assignee: Sharp Laboratories of Amrica, Inc.
    Inventors: Sheng Teng Hsu, Tingkai Li, Wei-Wei Zhuang
  • Publication number: 20080006862
    Abstract: A compound semiconductor-on-silicon (Si) wafer with a Si nanowire buffer layer is provided, along with a corresponding fabrication method. The method forms a Si substrate. An insulator layer is formed overlying the Si substrate, with Si nanowires having exposed tips. Compound semiconductor is selectively deposited on the Si nanowire tips. A lateral epitaxial overgrowth (LEO) process grows compound semiconductor from the compound semiconductor-coated Si nanowire tips, to form a compound semiconductor layer overlying the insulator. Typically, the insulator layer overlying the Si substrate is a thermally soft insulator (TSI), silicon dioxide, or SiXNY, where X?3 and Y?4. The compound semiconductor can be GaN, GaAs, GaAlN, or SiC. In one aspect, the Si nanowire tips are carbonized, and SiC is selectively deposited overlying the carbonized Si nanowire tips, prior to the selective deposition of compound semiconductor on the Si nanowire tips.
    Type: Application
    Filed: July 6, 2006
    Publication date: January 10, 2008
    Inventors: Tingkai Li, Sheng Teng Hsu
  • Publication number: 20080006814
    Abstract: A metal/semiconductor/metal (MSM) binary switch memory device and fabrication process are provided. The device includes a memory resistor bottom electrode, a memory resistor material over the memory resistor bottom electrode, and a memory resistor top electrode over the memory resistor material. An MSM bottom electrode overlies the memory resistor top electrode, a semiconductor layer overlies the MSM bottom electrode, and an MSM top electrode overlies the semiconductor layer. The MSM bottom electrode can be a material such as Pt, Ir, Au, Ag, TiN, or Ti. The MSM top electrode can be a material such as Pt, Ir, Au, TiN, Ti, or Al. The semiconductor layer can be amorphous Si, ZnO2, or InO2.
    Type: Application
    Filed: September 15, 2007
    Publication date: January 10, 2008
    Inventors: Sheng Hsu, Tingkai Li
  • Publication number: 20080003697
    Abstract: A method of fabricating a conductive metal oxide gate ferroelectric memory transistor includes forming an oxide layer a substrate and removing the oxide layer in a gate area; depositing a conductive metal oxide layer on the oxide layer and on the exposed gate area; depositing a titanium layer on the metal oxide layer; patterning and etching the titanium layer and the metal oxide layer to remove the titanium layer and the metal oxide layer from the substrate except in the gate area; depositing, patterning and etching an oxide layer to form a gate trench; depositing and etching a barrier insulator layer to form a sidewall barrier in the gate trench; removing the titanium layer from the gate area; depositing, smoothing and annealing a ferroelectric layer in the gate trench; depositing, patterning and etching a top electrode; and completing the conductive metal oxide gate ferroelectric memory transistor.
    Type: Application
    Filed: August 30, 2005
    Publication date: January 3, 2008
    Inventors: Tingkai Li, Sheng Hsu, Bruce Ulrich
  • Publication number: 20070284575
    Abstract: A method is provided for forming a metal/semiconductor/metal (MSM) current limiter and resistance memory cell with an MSM current limiter. The method comprises: providing a substrate; forming an MSM bottom electrode overlying the substrate; forming a ZnOx semiconductor layer overlying the MSM bottom electrode, where x is in the range between about 1 and about 2, inclusive; and, forming an MSM top electrode overlying the semiconductor layer. The ZnOx semiconductor can be formed through a number of different processes such as spin-coating, direct current (DC) sputtering, radio frequency (RF) sputtering, metalorganic chemical vapor deposition (MOCVD), or atomic layer deposition (ALD).
    Type: Application
    Filed: August 15, 2007
    Publication date: December 13, 2007
    Inventors: Tingkai Li, Sheng Hsu, Wei-Wei Zhuang, David Evans
  • Publication number: 20070278574
    Abstract: A method is provided for forming a compound semiconductor-on-silicon (Si) wafer with a thermally soft insulator. The method forms a Si substrate, with a thermally soft insulator layer overlying the Si substrate. A silicon oxide layer is formed immediately overlying the thermally soft insulator layer, a top Si layer overlies the silicon oxide, and a lattice mismatch buffer layer overlies the top Si layer. A compound semiconductor layer is formed overlying the lattice mismatch buffer layer. The thermally soft insulator has a liquid phase temperature lower than the liquid phase temperatures of Si and the compound semiconductor. For example, the thermally soft insulator may have a flow temperature in the range of about 500° C. to 900° C., where the flow temperature is greater than the solid phase temperature and less than the liquid phase temperature.
    Type: Application
    Filed: May 30, 2006
    Publication date: December 6, 2007
    Inventors: Sheng Teng Hsu, Tingkai Li, Jong-Jan Lee
  • Patent number: 7303971
    Abstract: A metal/semiconductor/metal (MSM) binary switch memory device and fabrication process are provided. The device includes a memory resistor bottom electrode, a memory resistor material over the memory resistor bottom electrode, and a memory resistor top electrode over the memory resistor material. An MSM bottom electrode overlies the memory resistor top electrode, a semiconductor layer overlies the MSM bottom electrode, and an MSM top electrode overlies the semiconductor layer. The MSM bottom electrode can be a material such as Pt, Ir, Au, Ag, TiN, or Ti. The MSM top electrode can be a material such as Pt, Ir, Au, TiN, Ti, or Al. The semiconductor layer can be amorphous Si, ZnO2, or InO2.
    Type: Grant
    Filed: July 18, 2005
    Date of Patent: December 4, 2007
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Tingkai Li
  • Publication number: 20070272960
    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: August 7, 2007
    Publication date: November 29, 2007
    Inventors: Sheng Hsu, Tingkai Li
  • Patent number: 7297642
    Abstract: A method is provided for forming a rare earth (RE) element-doped silicon (Si) oxide film with nanocrystalline (nc) Si particles. The method comprises: providing a first target of Si, embedded with a first rare earth element; providing a second target of Si; co-sputtering the first and second targets; forming a Si-rich Si oxide (SRSO) film on a substrate, doped with the first rare earth element; and, annealing the rare earth element-doped SRSO film. The first target is doped with a rare earth element such as erbium (Er), ytterbium (Yb), cerium (Ce), praseodymium (Pr), or terbium (Tb). The sputtering power is in the range of about 75 to 300 watts (W). Different sputtering powers are applied to the two targets. Also, deposition can be controlled by varying the effective areas of the two targets. For example, one of the targets can be partially covered.
    Type: Grant
    Filed: January 18, 2006
    Date of Patent: November 20, 2007
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Wei Gao, Tingkai Li, Robert A. Barrowcliff, Yoshi Ono, Sheng Teng Hsu
  • Patent number: 7297602
    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: Grant
    Filed: September 9, 2003
    Date of Patent: November 20, 2007
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Tingkai Li
  • Publication number: 20070238203
    Abstract: A method of monitoring synthesis of PCMO precursor solutions includes preparing a PCMO precursor solution and withdrawing samples of the precursor solution at intervals during a reaction phase of the PCMO precursor solution synthesis. The samples of the PCMO precursor solution are analyzed by UV spectroscopy to determine UV transmissivity of the samples of the PCMO precursor solution and the samples used to form PCMO thin films. Electrical characteristics of the PCMO thin films formed from the samples are determined to identify PCMO thin films having optimal electrical characteristics. The UV spectral characteristics of the PCMO precursor solutions are correlated with the PCMO thin films having optimal electrical characteristics. The UV spectral characteristics are used to monitor synthesis of future batches of the PCMO precursor solutions, which will result in PCMO thin films having optimal electrical characteristics.
    Type: Application
    Filed: April 11, 2006
    Publication date: October 11, 2007
    Inventors: Wei-Wei Zhuang, David Evans, Tingkai Li, Sheng Hsu
  • Publication number: 20070238239
    Abstract: A method is provided for forming a rare earth element-doped silicon oxide (SiO2) precursor with nanocrystalline (nc) Si particles. In one aspect the method comprises: mixing Si particles into a first organic solvent, forming a first solution with a first boiling point; filtering the first solution to remove large Si particles; mixing a second organic solvent having a second boiling point, higher than the first boiling point, to the filtered first solution; and, fractionally distilling, forming a second solution of nc Si particles. The Si particles are formed by immersing a Si wafer into a third solution including hydrofluoric (HF) acid and alcohol, applying an electric bias, and forming a porous Si layer overlying the Si wafer. Then, the Si particles are mixed into the organic solvent by depositing the Si wafer into the first organic solvent, and ultrasonically removing the porous Si layer from the Si wafer.
    Type: Application
    Filed: September 12, 2005
    Publication date: October 11, 2007
    Inventors: Wei-Wei Zhuang, Yoshi Ono, Sheng Teng-Hsu, Tingkai Li
  • Publication number: 20070238246
    Abstract: A method of fabricating a RRAM includes preparing a substrate and forming a bottom electrode ori the substrate. A PCMO layer is deposited on the bottom electrode using MOCVD or liquid MOCVD, followed by a post-annealing process. The deposited PCMO thin film has a crystallized PCMO structure or a nano-size and amorphous PCMO structure. A top electrode is formed on the PCMO layer.
    Type: Application
    Filed: April 11, 2006
    Publication date: October 11, 2007
    Inventors: Tingkai Li, Sheng Hsu, David Evans