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).
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Patent number: 6420740Abstract: The ferroelectric structure including a Pt/Ir layered electrode used in conjunction with a lead germanate (Pb5Ge3O11) thin film is provided. The electrode exhibits good adhesion to the substrate, and barrier properties resistant to oxygen and lead. Ferroelectric properties are improved, without detriment to the leakage current, by using a thin IrO2 layer formed in situ, during the MOCVD lead germanate (Pb5Ge3O11) thin film process. By using a Pt/Ir electrode, a relatively low MOCVD processing temperature is required to achieve c-axis oriented lead germanate (Pb5Ge3O11) thin film. The temperature range of MOCVD caxis oriented lead germanate (Pb5Ge3O11) thin film on top of Pt/Ir is 400-500° C. Further, a relatively large nucleation density is obtained, as compared to using single-layer iridium electrode. Therefore, the lead germanate (Pb5Ge3O11) thin film has a smooth surface, a homogeneous microstructure, and homogeneous ferroelectric properties.Type: GrantFiled: May 24, 1999Date of Patent: July 16, 2002Assignee: Sharp Laboratories of America, Inc.Inventors: Fengyan Zhang, Tingkai Li, Sheng Teng Hsu
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Patent number: 6410346Abstract: A Pb3GeO5 phase PGO thin film is provided. This film has ferroelastic properties that make it ideal for many microelectromechanical applications or as decoupling capacitors in high speed multichip modules. This PGO film is uniquely formed in a MOCVD process that permits a thin film, less than 1 mm, of material to be deposited. The process mixes Pd and germanium in a solvent. The solution is heated to form a precursor vapor which is decomposed. The method provides deposition temperatures and pressures. The as-deposited film is also annealed to enhanced the film's ferroelastic characteristics. A ferroelastic capacitor made from the present invention PGO film is also provided.Type: GrantFiled: December 6, 2001Date of Patent: June 25, 2002Assignee: Sharp Laboratories of America, Inc.Inventors: Tingkai Li, Fengyan Zhang, Yoshi Ono, Sheng Teng Hsu
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Patent number: 6410343Abstract: A ferroelectric Pb5Ge3O11 (PGO) thin film is provided with a metal organic vapor deposition (MOCVD) process and RTP (Rapid Thermal Process) annealing techniques. The PGO film is substantially crystallization with c-axis orientation at temperature between 450 and 650° C. The PGO film has an average grain size of about 0.5 microns, with a deviation in grain size uniformity of less than 10%. Good ferroelectric properties are obtained for a 150 nm thick film with Ir electrodes. The films also show fatigue-free characteristics: no fatigue was observed up to 1×109 switching cycles. The leakage currents increase with increasing applied voltage, and are about 3.6×10−7A/cm2 at 100 kV/cm. The dielectric constant shows a behavior similar to most ferroelectric materials, with a maximum dielectric constant of about 45. These high quality MOCVD Pb5Ge3O11 films can be used for high density single transistor ferroelectric memory applications because of the homogeneity of the PGO film grain size.Type: GrantFiled: April 28, 1999Date of Patent: June 25, 2002Assignee: Sharp Laboratories of America, Inc.Inventors: Tingkai Li, Fengyan Zhang, Yoshi Ono, Sheng Teng Hsu
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Publication number: 20020063265Abstract: A Pb3GeO5 phase PGO thin film is provided. This film has ferroelastic properties that make it ideal for many microelectromechanical applications or as decoupling capacitors in high speed multichip modules. This PGO film is uniquely formed in a MOCVD process that permits a thin film, less than 1 mm, of material to be deposited. The process mixes Pd and germanium in a solvent. The solution is heated to form a precursor vapor which is decomposed. The method provides deposition temperatures and pressures. The as-deposited film is also annealed to enhanced the film's ferroelastic characteristics. A ferroelastic capacitor made from the present invention PGO film is also provided.Type: ApplicationFiled: December 6, 2001Publication date: May 30, 2002Inventors: Tingkai Li, Fengyan Zhang, Yoshi Ono, Sheng Teng Hsu
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Publication number: 20020024072Abstract: A Pb3GeO5 phase PGO thin film is provided. This film has ferroelastic properties that make it ideal for many microelectromechanical applications or as decoupling capacitors in high speed multichip modules. This PGO film is uniquely formed in a MOCVD process that permits a thin film, less than 1 mm, of material to be deposited. The process mixes Pd and germanium in a solvent. The solution is heated to form a precursor vapor which is decomposed. The method provides deposition temperatures and pressures. The as-deposited film is also annealed to enhanced the film's ferroelastic characteristics. A ferroelastic capacitor made from the present invention PGO film is also provided.Type: ApplicationFiled: April 28, 1999Publication date: February 28, 2002Inventors: TINGKAI LI, FENGYAN ZHANG, YOSHI ONO, SHENG TENG HSU
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Publication number: 20020022278Abstract: A ferroelectric Pb5Ge3O11 (PGO) thin film is provided with a metal organic vapor deposition (MOCVD) process and RTP (Rapid Thermal Process) annealing techniques. The PGO film is substantially crystallization with c-axis orientation at temperature between 450 and 650° C. The PGO film has an average grain size of about 0.5 microns, with a deviation in grain size uniformity of less than 10%. Good ferroelectric properties are obtained for a 150 nm thick film with Ir electrodes. The films also show fatigue-free characteristics: no fatigue was observed up to 1×109 switching cycles. The leakage currents increase with increasing applied voltage, and are about 3.6×10−7 A/cm2 at 100 kV/cm. The dielectric constant shows a behavior similar to most ferroelectric materials, with a maximum dielectric constant of about 45. These high quality MOCVD Pb5Ge3O11 films can be used for high density single transistor ferroelectric memory applications because of the homogeneity of the PGO film grain size.Type: ApplicationFiled: August 29, 2001Publication date: February 21, 2002Inventors: Tingkai Li, Fengyan Zhang, Yoshi Ono, Sheng Tang Hsu
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Publication number: 20020018904Abstract: A ferroelectric Pb5Ge3O11 (PGO) thin film is provided with a metal organic vapor deposition (MOCVD) process and RTP (Rapid Thermal Process) annealing techniques. The PGO film is substantially crystallization with c-axis orientation at temperature between 450 and 650° C. The PGO film has an average grain size of about 0.5 microns, with a deviation in grain size uniformity of less than 10%. Good ferroelectric properties are-obtained for a 150 nm thick film with Ir electrodes. The films also show fatigue-free characteristics: no fatigue was observed up to 1×109 switching cycles. The leakage currents increase with increasing applied voltage, and are about 3.6×10−7 A/cm2 at 100 kV/cm. The dielectric constant shows a behavior similar to most ferroelectric materials, with a maximum dielectric constant of about 45. These high quality MOCVD Pb5Ge3O11 films can be used for high density single transistor ferroelectric memory applications because of the homogeneity of the PGO film grain size.Type: ApplicationFiled: August 29, 2001Publication date: February 14, 2002Inventors: Tingkai Li, Fengyan Zhang, Yoshi Ono, Sheng Teng Hsu
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Patent number: 6303502Abstract: A method of fabricating a one-transistor memory includes, on a single crystal silicon substrate, depositing a bottom electrode structure on a gate oxide layer; implanting ions to form a source region and a drain region and activating the implanted ions spin coating the structure with a first ferroelectric layer; depositing a second ferroelectric layer; and annealing the structure to provide a c-axis ferroelectric orientation.Type: GrantFiled: June 6, 2000Date of Patent: October 16, 2001Assignee: Sharp Laboratories of America, Inc.Inventors: Sheng Teng Hsu, David R. Evans, Tingkai Li, Jer-shen Maa, Wei-Wei Zhuang
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Publication number: 20010024835Abstract: A Pb3GeO5 phase PGO thin film is provided. This film has ferroelastic properties that make it ideal for many microelectromechanical applications or as decoupling capacitors in high speed multichip modules. This PGO film is uniquely formed in a MOCVD process that permits a thin film, less than 1 mm, of material to be deposited. The process mixes Pd and germanium in a solvent. The solution is heated to form a precursor vapor which is decomposed. The method provides deposition temperatures and pressures. The as-deposited film is also annealed to enhanced the film's ferroelastic characteristics. A ferroelastic capacitor made from the present invention PGO film is also provided.Type: ApplicationFiled: March 21, 2001Publication date: September 27, 2001Inventors: Tingkai Li, Fengyan Zhang, Yoshi Ono, Sheng Teng Hsu
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Patent number: 6281022Abstract: A MOCVD deposition process has been provided for the deposition of an improved PGO ferroelectric film. The inclusion of a second phase of Pb3GeO5, along with the first phase of Pb5Ge3O11, provides the film with some ferroelastic properties which direct correspond to improved ferroelectric characteristics. The inclusion of the second phase regulates to first phase crystal grain size and promotes the preferred c-axis orientation of the grains. The degree of second phase Pb3GeO5 is regulated by controlling the amount of lead in the precursor, and with additional lead added to the reactor along the oxygen used to oxidize the lead-germanium film. Critical post-deposition annealing process are also described which optimize the ferroelectric properties of the PGO film. A multi-phase PGO film and capacitor structure including multi-phase PGO film of the present invention are provided by means of the invention.Type: GrantFiled: November 1, 2000Date of Patent: August 28, 2001Assignee: Sharp Laboratories of America, Inc.Inventors: Tingkai Li, Fengyan Zhang, Sheng Teng Hsu
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Patent number: 6190925Abstract: The present invention provides a substantially single crystal PGO film with optimal the ferroelectric properties. The PGO film and adjacent electrodes are epitaxially grown to minimize mismatch between the structures. MOCVD deposition methods and RTP annealing procedures permit a PGO film to be epitaxially grown in commercial fabrication processes. These epitaxial ferroelectric have application in FeRAM memory devices. The present invention deposition method epitaxially grows ferroelectric Pb5Ge3O11 thin films along with c-axis orientation.Type: GrantFiled: April 28, 1999Date of Patent: February 20, 2001Assignee: Sharp Laboratories of America, Inc.Inventors: Tingkai Li, Fengyan Zhang, Yoshi Ono, Sheng Teng Hsu
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Patent number: 6080241Abstract: A chemical vapor deposition (CVD) reactor for growing epitaxial layers on wafers includes a chamber having an interior region and exterior region. The chamber includes one or more apertures extending therethrough for passing reactant gases from the exterior region of the chamber to the interior region of the chamber. The CVD reactor also includes one or more reactant gas injectors which are releasably secured to the one or more apertures in the chamber. Each reactant gas injector includes one or more passageways for passing reactant gas through the apertures in the chamber and into the interior region of the chamber. At least one of the injectors is releasably secured to the apertures so that the injector(s) may be removed from the aperture(s) of the chamber without entering the interior region of the chamber.Type: GrantFiled: September 2, 1998Date of Patent: June 27, 2000Assignee: Emcore CorporationInventors: Tingkai Li, Dane C. Scott, Brian Wyckoff
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Patent number: 6048740Abstract: A method of fabricating a ferroelectric memory transistor using a lithographic process having an alignment tolerance of .delta., includes preparing a silicon substrate for construction of a ferroelectric gate unit; implanting boron ions to form a p- well in the substrate; isolating plural device areas on the substrate; forming a FE gate stack surround structure; etching the FE gate stack surround structure to form an opening having a width of L1 to expose the substrate in a gate region; depositing oxide to a thickness of between about 10 nm to 40 nm over the exposed substrate; forming a FE gate stack over the gate region, wherein the FE gate stack has a width of L2, wherein L2.gtoreq.L1+2.delta.; depositing a first insulating layer over the structure; implanting arsenic or phosphorous ions to form a source region and a drain region; annealing the structure; depositing a second insulating layer; and metallizing the structure.Type: GrantFiled: November 5, 1998Date of Patent: April 11, 2000Assignee: Sharp Laboratories of America, Inc.Inventors: Sheng Teng Hsu, Jer-shen Maa, Fengyang Zhang, Tingkai Li
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Patent number: 5527567Abstract: A method of fabricating high quality layered structure oxide ferroelectric thin films. The deposition process is a chemical vapor deposition process involving chemical reaction between volatile metal organic compounds of various elements comprising the layered structure material to be deposited, with other gases in a reactor, to produce a nonvolatile solid that deposits on a suitably placed substrate such as a conducting, semiconducting, insulating, or complex integrated circuit substrate. The source materials for this process may include organometallic compounds such as alkyls, alkoxides, .beta.-diketonates or metallocenes of each individual element comprising the layered structure material to be deposited and oxygen. Preferably, the reactor in which the deposition is done is either a hot wall or a cold wall reactor and the vapors are introduced into this reactor either through a set of bubblers or through a direct liquid injection system.Type: GrantFiled: May 30, 1995Date of Patent: June 18, 1996Assignees: Ceram Incorporated, Sharp Kabushiki Kaisha, Virginia Tech Intellectual Properties, IncInventors: Seshu B. Desu, Wei Tao, Chien H. Peng, Tingkai Li, Yongfei Zhu
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Patent number: 5268199Abstract: Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure are created using sol-gel processes. The processes have particular application in creating calcium magnesium zirconium phosphate, CMZP, coatings and foams.Type: GrantFiled: April 2, 1993Date of Patent: December 7, 1993Assignees: The Center of Innovative Technology, Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventors: Jesse J. Brown, Jr., Deidre A. Hirschfeld, Tingkai Li
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Patent number: 5102836Abstract: Compositions having the general formula (Ca.sub.x Mg.sub.1-x)Zr.sub.4 (PO.sub.4).sub.6 where x is between 0.5 and 0.99 are produced by solid state and sol-gel processes. In a preferred embodiment, when x is between 0.5 and 0.8, the MgCZP materials have near-zero coefficients of thermal expansion. The MgCZPs of the present invention also show unusually low thermal conductivities, and are stable at high temperatures. Macrostructures formed from MgCZP are useful in a wide variety of high-temperature applications. In a preferred process, calcium, magnesium, and zirconium nitrate solutions have their pH adjusted to between 7 and 9 either before or after the addition of ammonium dihydrogen phosphate. After dehydration to a gel, and calcination at temperatures in excess of 850.degree. C. for approximately 16 hours, single phase crystalline MgCZP powders with particle sizes ranging from approximately 20 nm to 50 nm result. The MgCZP powders are then sintered at temperatures ranging from 1200.degree. C. to 1350.Type: GrantFiled: June 6, 1990Date of Patent: April 7, 1992Assignees: Center for Innovative Technology, Virginia Tech Intellectual Properties, Inc., Virginia Polytechnic and State UniversityInventors: Jesse Brown, Deidre Hirschfeld, Dean-Mo Liu, Yaping Yang, Tingkai Li, Robert E. Swanson, Steven Van Aken, Jin-Min Kim