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: 7514282
    Abstract: An array of submicron silicon (Si) tubes is provided with a method for patterning submicron Si tubes. The method provides a Si substrate, and forms a silicon dioxide film overlying the Si substrate. An array of silicon dioxide rods is formed from the silicon dioxide film, and Si3N4 tubes are formed surrounding the silicon dioxide rods. The silicon dioxide rods are etched away. Then, exposed regions of the Si substrate are etched, forming Si tubes underlying the Si3N4 tubes. Finally, the Si3N4 tubes are removed.
    Type: Grant
    Filed: January 4, 2007
    Date of Patent: April 7, 2009
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Jong-Jan Lee, Jer-Shen Maa, Sheng Teng Hsu
  • Publication number: 20090032817
    Abstract: A method is provided for forming a metal/semiconductor/metal (MSM) back-to-back Schottky diode from a silicon (Si) semiconductor. The method deposits a Si semiconductor layer between a bottom electrode and a top electrode, and forms a MSM diode having a threshold voltage, breakdown voltage, and on/off current ratio. The method is able to modify the threshold voltage, breakdown voltage, and on/off current ratio of the MSM diode in response to controlling the Si semiconductor layer thickness. Generally, both the threshold and breakdown voltage are increased in response to increasing the Si thickness. With respect to the on/off current ratio, there is an optimal thickness. The method is able to form an amorphous Si (a-Si) and polycrystalline Si (polySi) semiconductor layer using either chemical vapor deposition (CVD) or DC sputtering. The Si semiconductor can be doped with a Group V donor material, which decreases the threshold voltage and increases the breakdown voltage.
    Type: Application
    Filed: September 21, 2008
    Publication date: February 5, 2009
    Inventors: Tingkai Li, Sheng Teng Hsu, David R. Evans
  • Publication number: 20090008647
    Abstract: A thermal expansion interface between silicon (Si) and gallium nitride (GaN) films using multiple buffer layers of aluminum compounds has been provided, along with an associated fabrication method. The method provides a (111) Si substrate and deposits a first layer of AlN overlying the substrate by heating the substrate to a relatively high temperature of 1000 to 1200° C. A second layer of AlN is deposited overlying the first layer of AlN at a lower temperature of 500 to 800° C. A third layer of AlN is deposited overlying the second layer of AlN by heating the substrate to the higher temperature range. Then, a grading Al1-XGaXN layer is formed overlying the third layer of AlN, where 0<X<1, followed by a fixed composition Al1-XGaXN layer overlying the first grading Al1-XGaXN layer. An epitaxial GaN layer can then be grown overlying the fixed composition Al1-XGaXN layer.
    Type: Application
    Filed: July 6, 2007
    Publication date: January 8, 2009
    Inventors: Tingkai Li, Douglas J. Tweet, Jer-Shen Maa, Sheng Teng Hsu
  • Publication number: 20080315255
    Abstract: A method is provided for forming a matching thermal expansion interface between silicon (Si) and gallium nitride (GaN) films. The method provides a (111) Si substrate with a first thermal expansion coefficient (TEC), and forms a silicon-germanium (SiGe) film overlying the Si substrate. A buffer layer is deposited overlying the SiGe film. The buffer layer may be aluminum nitride (AlN) or aluminum-gallium nitride (AlGaN). A GaN film is deposited overlying the buffer layer having a second TEC, greater than the first TEC. The SiGe film has a third TEC, with a value in between the first and second TECs. In one aspect, a graded SiGe film may be formed having a Ge content ratio in a range of about 0% to 50%, where the Ge content increases with the graded SiGe film thickness.
    Type: Application
    Filed: August 27, 2008
    Publication date: December 25, 2008
    Inventors: Jer-Shen Maa, Tingkai Li, Douglas J. Tweet, Gregory M. Stecker, Sheng Teng Hsu
  • Publication number: 20080296616
    Abstract: A method is provided for forming a matching thermal expansion interface between silicon (Si) and gallium nitride (GaN) films. The method provides a (111) Si substrate that is heated to a temperature in a range of about 300 to 800° C., and a first film is formed in compression overlying the Si substrate. The first film material may be InP, SiGe, GaP, GaAs, AlN, AlGaN, an AlN/graded AlGaN (Al1?xGaxN (0<x<1)) stack, or a AlN/graded AlGaN/GaN stack. The first film is then nanoscale patterned and a lateral nanoheteroepitaxy overgrowth (LNEO) process is used to grow a first GaN layer. The above-mentioned processes are repeated, forming a second film in compression that is nanoscale patterned, and a second GaN layer is grown using the LNEO process. The first and second GaN layers are formed by heating the Si substrate to a temperature in a range of 1000 to 1200° C.
    Type: Application
    Filed: June 4, 2007
    Publication date: December 4, 2008
    Inventors: Tingkai Li, Douglas J. Tweet, Jer-Shen Maa, Sheng Teng Hsu
  • Publication number: 20080296625
    Abstract: A multilayer thermal expansion interface between silicon (Si) and gallium nitride (GaN) films is provided, along with an associated fabrication method. The method provides a (111) Si substrate and forms a first layer of a first film overlying the substrate. The Si substrate is heated to a temperature in the range of about 300 to 800° C., and the first layer of a second film is formed in compression overlying the first layer of the first film. Using a lateral nanoheteroepitaxy overgrowth (LNEO) process, a first GaN layer is grown overlying the first layer of second film. Then, the above-mentioned processes are repeated: forming a second layer of first film; heating the substrate to a temperature in the range of about 300 to 800° C.; forming a second layer of second film in compression; and, growing a second GaN layer using the LNEO process.
    Type: Application
    Filed: June 4, 2007
    Publication date: December 4, 2008
    Inventors: Tingkai Li, Douglas J. Tweet, Jer-Shen Maa, Sheng Teng Hsu
  • Publication number: 20080280426
    Abstract: A method is provided for forming a matching thermal expansion interface between silicon (Si) and gallium nitride (GaN) films. The method provides a (111) Si substrate and forms a first aluminum (Al)-containing film in compression overlying the Si substrate. Nano-column holes are formed in the first Al-containing film, which exposes regions of the underlying Si substrate. A layer of GaN layer is selectively grown from the exposed regions, covering the first Al-containing film. The GaN is grown using a lateral nanoheteroepitaxy overgrowth (LNEO) process. The above-mentioned processes are reiterated, forming a second Al-containing film in compression, forming nano-column holes in the second Al-containing film, and selectively growing a second GaN layer. Film materials such as Al2O3, Si1-xGex, InP, GaP, GaAs, AlN, AlGaN, or GaN, may be initially grown at a low temperature. By increasing the growth temperatures, a compressed layer of epitaxial GaN can be formed on a Si substrate.
    Type: Application
    Filed: May 9, 2007
    Publication date: November 13, 2008
    Inventors: Tingkai Li, Douglas J. Tweet, Jer-Shen Maa, Sheng Teng Hsu
  • Patent number: 7446010
    Abstract: A method is provided for forming a metal/semiconductor/metal (MSM) back-to-back Schottky diode from a silicon (Si) semiconductor. The method deposits a Si semiconductor layer between a bottom electrode and a top electrode, and forms a MSM diode having a threshold voltage, breakdown voltage, and on/off current ratio. The method is able to modify the threshold voltage, breakdown voltage, and on/off current ratio of the MSM diode in response to controlling the Si semiconductor layer thickness. Generally, both the threshold and breakdown voltage are increased in response to increasing the Si thickness. With respect to the on/off current ratio, there is an optimal thickness. The method is able to form an amorphous Si (a-Si) and polycrystalline Si (polySi) semiconductor layer using either chemical vapor deposition (CVD) or DC sputtering. The Si semiconductor can be doped with a Group V donor material, which decreases the threshold voltage and increases the breakdown voltage.
    Type: Grant
    Filed: May 17, 2006
    Date of Patent: November 4, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu, David R. Evans
  • Patent number: 7407858
    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: Grant
    Filed: April 11, 2006
    Date of Patent: August 5, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Sheng Teng Hsu, David R. Evans
  • Publication number: 20080173895
    Abstract: A method is provided for forming a matching thermal expansion interface between silicon (Si) and gallium nitride (GaN) films. The method provides a (111) Si substrate with a first thermal expansion coefficient (TEC), and forms a silicon-germanium (SiGe) film overlying the Si substrate. A buffer layer is deposited overlying the SiGe film. The buffer layer may be aluminum nitride (AlN) or aluminum-gallium nitride (AlGaN). A GaN film is deposited overlying the buffer layer having a second TEC, greater than the first TEC. The SiGe film has a third TEC, with a value in between the first and second TECs. In one aspect, a graded SiGe film may be formed having a Ge content ratio in a range of about 0% to 50%, where the Ge content increases with the graded SiGe film thickness.
    Type: Application
    Filed: January 24, 2007
    Publication date: July 24, 2008
    Inventors: Jer-Shen Maa, Tingkai Li, Douglas J. Tweet, Gregory M. Stecker, Sheng Teng Hsu
  • Patent number: 7402456
    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: Grant
    Filed: April 23, 2004
    Date of Patent: July 22, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Wei-Wei Zhuang, Tingkai Li, Sheng Teng Hsu, Fengyan Zhang
  • Publication number: 20080171424
    Abstract: A method of fabricating a continuous layer of a defect sensitive material on a silicon substrate includes preparing a silicon substrate; forming a nanostructure array directly on the silicon substrate; depositing a selective growth enhancing layer on the substrate; smoothing the selective growth enhancing layer; and growing a continuous layer of the defect sensitive material on the nanostructure array.
    Type: Application
    Filed: January 16, 2007
    Publication date: July 17, 2008
    Inventors: Tingkai Li, Jer-Shen Maa, Douglas J. Tweet, Wei-Wei Zhuang, Sheng Teng Hsu
  • Publication number: 20080166878
    Abstract: A method of fabricating silicon nanostructures includes preparing a silicon wafer as a substrate; forming an oxide layer hardmask directly on the silicon substrate; patterning and etching the oxide hardmask; wet etching the silicon wafer to remove oxide to reduce the size of the oxide hardmask and to form nanostructure elements; and dry etching, in one or more steps, the silicon wafer using the oxide hardmask to form a desired nanostructure having substantially parallel vertical sidewalls thereon.
    Type: Application
    Filed: January 8, 2007
    Publication date: July 10, 2008
    Inventors: Tingkai Li, Bruce D. Ulrich, Jer-Shen Maa, Sheng Teng Hsu
  • Publication number: 20080164569
    Abstract: A method of fabricating an electroluminescent device includes, on a prepared substrate, depositing a rare earth-doped silicon-rich layer on gate oxide layer as a light emitting layer; and annealing and oxidizing the structure to repair any damage caused to the rare earth-doped silicon-rich layer; and incorporating the electroluminescent device into a CMOS IC. An electroluminescent device fabricated according to the method of the invention includes a substrate, a rare earth-doped silicon-rich layer formed on the gate oxide layer for emitting a light of a pre-determined wavelength; a top electrode formed on the rare earth-doped silicon-rich layer; and associated CMOS IC structures fabricated thereabout.
    Type: Application
    Filed: October 16, 2006
    Publication date: July 10, 2008
    Inventors: Tingkai Li, Wei Gao, Yoshi Ono, Sheng Teng Hsu
  • Publication number: 20080164577
    Abstract: An array of submicron silicon (Si) tubes is provided with a method for patterning submicron Si tubes. The method provides a Si substrate, and forms a silicon dioxide film overlying the Si substrate. An array of silicon dioxide rods is formed from the silicon dioxide film, and Si3N4 tubes are formed surrounding the silicon dioxide rods. The silicon dioxide rods are etched away. Then, exposed regions of the Si substrate are etched, forming Si tubes underlying the Si3N4 tubes. Finally, the Si3N4 tubes are removed.
    Type: Application
    Filed: January 4, 2007
    Publication date: July 10, 2008
    Inventors: Tingkai Li, Jong-Jan Lee, Jer-Shen Maa, Sheng Teng Hsu
  • Publication number: 20080149941
    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: February 25, 2008
    Publication date: June 26, 2008
    Inventors: Tingkai Li, Sheng Teng Hsu
  • Patent number: 7378286
    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: Grant
    Filed: August 20, 2004
    Date of Patent: May 27, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Tingkai Li, Jong-Jan Lee
  • Patent number: 7379320
    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: October 28, 2005
    Date of Patent: May 27, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Sheng Teng Hsu, Fengyan Zhang, Tingkai Li
  • Patent number: 7364665
    Abstract: A method of selectively etching a three-layer structure consisting of SiO2, In2O3, and titanium, includes etching the SiO2, stopping at the titanium layer, using C3F8 in a range of between about 10 sccm to 30 sccm; argon in a range of between about 20 sccm to 40 sccm, using an RF source in a range of between about 1000 watts to 3000 watts and an RF bias in a range of between about 400 watts to 800 watts at a pressure in a range of between about 2 mtorr to 6 mtorr; and etching the titanium, stopping at the In2O3 layer, using BCl in a range of between about 10 sccm to 50 sccm; chlorine in a range of between about 40 sccm to 80 sccm, a Tcp in a range of between about 200 watts to 500 watts at an RF bias in a range of between about 100 watts to 200 watts at a pressure in a range of between about 4 mtorr to 8 mtorr.
    Type: Grant
    Filed: October 21, 2004
    Date of Patent: April 29, 2008
    Assignee: Sharp Laboratories of America, Inc.
    Inventors: Tingkai Li, Bruce D. Ulrich, David R. Evans, Sheng Teng Hsu
  • Publication number: 20080090317
    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: Application
    Filed: November 29, 2007
    Publication date: April 17, 2008
    Inventors: Sheng Hsu, Tingkai Li, Wei-Wei Zhuang