Patents by Inventor Xuefeng Liu

Xuefeng Liu 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: 8860937
    Abstract: Various metrology systems and methods for high aspect ratio and large lateral dimension structures are provided. One method includes directing light to one or more structures formed on a wafer. The light includes ultraviolet light, visible light, and infrared light. The one or more structures include at least one high aspect ratio structure or at least one large lateral dimension structure. The method also includes generating output responsive to light from the one or more structures due to the light directed to the one or more structures. In addition, the method includes determining one or more characteristics of the one or more structures using the output.
    Type: Grant
    Filed: January 16, 2013
    Date of Patent: October 14, 2014
    Assignee: KLA-Tencor Corp.
    Inventors: Thaddeus Gerard Dziura, Xuefeng Liu, David Y. Wang, Jonathan Madsen, Alexander Kuznetsov, Johannes D. de Veer, Shankar Krishnan, Derrick Shaughnessy, Andrei Shchegrov
  • Publication number: 20140253713
    Abstract: A single-photon or ultra-weak light multi-D imaging spectral system and method. In order to realize rough time resolution, a time-resolved single-photon counting 2D imaging system for forming color or grey imaging is provided. Moreover, in order to realize high-precision time resolution, the system comprises a light source, an imaging spectral measurement unit, an electric detection unit, a system control unit and an algorithm unit. The light carrying information of an object is imaged on a spatial light modulator and randomly modulated according to compressed sensing theory, emergent light of a grating is collected using a point or array single-photon detector, the number of photons and photon arrival time are recorded, and reconstruction is carried out using the compressed sensing algorithm and related algorithm of the spectral imaging. The system provides single-photon detection sensitivity, high time resolution and wide spectral range, and can be applied in numerous new high-tech industries.
    Type: Application
    Filed: May 14, 2012
    Publication date: September 11, 2014
    Inventors: Guangjie Zhai, Wenkai Yu, Xuefeng Liu, Xuri Yao, Chao Wang, Zhibin Sun
  • Patent number: 8832611
    Abstract: Systems and methods for process aware metrology are provided. One method includes selecting nominal values and one or more different values of process parameters for one or more process steps used to form the structure on the wafer, simulating one or more characteristics of the structure that would be formed on the wafer using the nominal values, and determining parameterization of the optical model based on how the one or more characteristics of the structure vary between at least two of the nominal values and the one or more different values.
    Type: Grant
    Filed: June 17, 2013
    Date of Patent: September 9, 2014
    Assignee: KLA-Tencor Corp.
    Inventors: Xuefeng Liu, Yung-Ho Alex Chuang, John Fielden, Bin-Ming Benjamin Tsai, Jingjing Zhang
  • Publication number: 20140239498
    Abstract: A trench contact silicide is formed on an inner wall of a contact trench that reaches to a buried conductive layer in a semiconductor substrate to reduce parasitic resistance of a reachthrough structure. The trench contact silicide is formed at the bottom, on the sidewalls of the trench, and on a portion of the top surface of the semiconductor substrate. The trench is subsequently filled with a middle-of-line (MOL) dielectric. A contact via may be formed on the trench contact silicide. The trench contact silicide may be formed through a single silicidation reaction with a metal layer or through multiple silicidation reactions with multiple metal layers.
    Type: Application
    Filed: August 9, 2012
    Publication date: August 28, 2014
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Douglas D. Coolbaugh, Jeffrey B. Johnson, Peter J. Lindgren, Xuefeng Liu, James S. Nakos, Bradley A. Orner, Robert M. Rassel, David C. Sheridan
  • Publication number: 20140235021
    Abstract: Disclosed are embodiments of a junction field effect transistor (JFET) structure with one or more P-type silicon germanium (SiGe) or silicon germanium carbide (SiGeC) gates (i.e., a SiGe or SiGeC based heterojunction JFET). The P-type SiGe or SiGeC gate(s) allow for a lower pinch off voltage (i.e., lower Voff) without increasing the on resistance (Ron). Specifically, SiGe or SiGeC material in a P-type gate limits P-type dopant out diffusion and, thereby ensures that the P-type gate-to-N-type channel region junction is more clearly defined (i.e., abrupt as opposed to graded). By clearly defining this junction, the depletion layer in the N-type channel region is extended. Extending the depletion layer in turn allows for a faster pinch off (i.e., requires lower Voff). P-type SiGe or SiGeC gate(s) can be incorporated into conventional lateral JFET structures and/or vertical JFET structures. Also disclosed herein are embodiments of a method of forming such a JFET structure.
    Type: Application
    Filed: April 29, 2014
    Publication date: August 21, 2014
    Applicant: International Business Machines Corporation
    Inventors: Xuefeng Liu, Richard A. Phelps, Robert M. Rassel, Xiaowei Tian
  • Patent number: 8809155
    Abstract: Device structures, design structures, and fabrication methods for a varactor. The device structure includes a first electrode formed on a dielectric layer, and a semiconductor body formed on the first electrode. The semiconductor body is comprised of a silicon-containing semiconductor material in an amorphous state or a polycrystalline state. The device structure further includes an electrode insulator formed on the semiconductor body and a second electrode formed on the electrode insulator.
    Type: Grant
    Filed: October 4, 2012
    Date of Patent: August 19, 2014
    Assignee: International Business Machines Corporation
    Inventors: John J. Ellis-Monaghan, Michael J. Hauser, Zhong-Xiang He, Xuefeng Liu, Richard A. Phelps, Robert M. Rassel, Anthony K. Stamper
  • Publication number: 20140222380
    Abstract: Electromagnetic modeling of finite structures and finite illumination for metrology and inspection are described herein. In one embodiment, a method for evaluating a diffracting structure involves providing a model of the diffracting structure. The method involves computing background electric or magnetic fields of an environment of the diffracting structure. The method involves computing scattered electric or magnetic fields from the diffracting structure using a scattered field formulation based on the computed background fields. The method further involves computing spectral information for the model of the diffracting structure based on the computed scattered fields, and comparing the computed spectral information for the model with measured spectral information for the diffracting structure. In response to a good model fit, the method involves determining a physical characteristic of the diffracting structure based on the model of the diffracting structure.
    Type: Application
    Filed: January 31, 2014
    Publication date: August 7, 2014
    Inventors: Alexander Kuznetsov, Kevin Peterlinz, Andrei Shchegrov, Leonid Poslavsky, Xuefeng Liu
  • Patent number: 8779476
    Abstract: A junction gate field-effect transistor (JFET) for an integrated circuit (IC) chip is provided comprising a source region, a drain region, a lower gate, and a channel, with an insulating shallow trench isolation (STI) region extending from an inner edge of an upper surface of the source region to an inner edge of an upper surface of the drain region, without an intentionally doped region, e.g., an upper gate, coplanar with an upper surface of the IC chip between the source/drain regions. In addition, an asymmetrical quasi-buried upper gate can be included, disposed under a portion of the STI region, but not extending under a portion of the STI region proximate to the drain region. Embodiments of this invention also include providing an implantation layer, under the source region, to reduce Ron. A related method and design structure are also disclosed.
    Type: Grant
    Filed: April 25, 2013
    Date of Patent: July 15, 2014
    Assignee: International Business Machines Corporation
    Inventors: Xuefeng Liu, Richard A. Phelps, Robert M. Rassel, Xiaowei Tian
  • Publication number: 20140183753
    Abstract: A semiconductor fabrication is described, wherein a MOS device and a MEMS device is fabricated simultaneously in the BEOL process. A silicon layer is deposited and etched to form a silicon film for a MOS device and a lower silicon sacrificial film for a MEMS device. A conductive layer is deposited atop the silicon layer and etched to form a metal gate and a first upper electrode. A dielectric layer is deposited atop the conductive layer and vias are formed in the dielectric layer. Another conductive layer is deposited atop the dielectric layer and etched to form a second upper electrode and three metal electrodes for the MOS device. Another silicon layer is deposited atop the other conductive layer and etched to form an upper silicon sacrificial film for the MEMS device. The upper and lower silicon sacrificial films are then removed via venting holes.
    Type: Application
    Filed: January 3, 2013
    Publication date: July 3, 2014
    Applicant: International Business Machines Corporation
    Inventors: John J. Ellis-Monaghan, Michael J. Hauser, Zhong-Xiang He, Junjun Li, Xuefeng Liu, Anthony K. Stamper
  • Patent number: 8754455
    Abstract: Disclosed are embodiments of a junction field effect transistor (JFET) structure with one or more P-type silicon germanium (SiGe) or silicon germanium carbide (SiGeC) gates (i.e., a SiGe or SiGeC based heterojunction JFET). The P-type SiGe or SiGeC gate(s) allow for a lower pinch off voltage (i.e., lower Voff) without increasing the on resistance (Ron). Specifically, SiGe or SiGeC material in a P-type gate limits P-type dopant out diffusion and, thereby ensures that the P-type gate-to-N-type channel region junction is more clearly defined (i.e., abrupt as opposed to graded). By clearly defining this junction, the depletion layer in the N-type channel region is extended. Extending the depletion layer in turn allows for a faster pinch off (i.e., requires lower Voff). P-type SiGe or SiGeC gate(s) can be incorporated into conventional lateral JFET structures and/or vertical JFET structures. Also disclosed herein are embodiments of a method of forming such a JFET structure.
    Type: Grant
    Filed: January 3, 2011
    Date of Patent: June 17, 2014
    Assignee: International Business Machines Corporation
    Inventors: Xuefeng Liu, Richard A. Phelps, Robert M. Rassel, Xiaowei Tian
  • Publication number: 20140097434
    Abstract: Device structures, design structures, and fabrication methods for a varactor. The device structure includes a first electrode formed on a dielectric layer, and a semiconductor body formed on the first electrode. The semiconductor body is comprised of a silicon-containing semiconductor material in an amorphous state or a polycrystalline state. The device structure further includes an electrode insulator formed on the semiconductor body and a second electrode formed on the electrode insulator.
    Type: Application
    Filed: October 4, 2012
    Publication date: April 10, 2014
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: John J. Ellis-Monaghan, Michael J. Hauser, Zhong-Xiang He, Xuefeng Liu, Richard A. Phelps, Robert M. Rassel, Anthony K. Stamper
  • Patent number: 8675188
    Abstract: Determination of one or more optical characteristics of a structure of a semiconductor wafer includes measuring one or more optical signals from one or more structures of a sample, determining a background optical field associated with a reference structure having a selected set of nominal characteristics based on the one or more structures, determining a correction optical field suitable for at least partially correcting the background field, wherein a difference between the measured one or more optical signals and a signal associated with a sum of the correction optical field and the background optical field is below a selected tolerance level, and extracting one or more characteristics associated with the one or more structures utilizing the correction optical field.
    Type: Grant
    Filed: January 4, 2013
    Date of Patent: March 18, 2014
    Assignee: KLA-Tencor Corporation
    Inventors: Xuefeng Liu, Yung-Ho Alex Chuang, John Fielden
  • Patent number: 8592293
    Abstract: A method for forming a Schottky barrier diode on a SiGe BiCMOS wafer, including forming a structure which provides a cutoff frequency (Fc) above about 1.0 THz. In embodiments, the structure which provides a cutoff frequency (Fc) above about 1.0 THz may include an anode having an anode area which provides a cutoff frequency (FC) above about 1.0 THz, an n-epitaxial layer having a thickness which provides a cutoff frequency (FC) above about 1.0 THz, a p-type guardring at an energy and dosage which provides a cutoff frequency (FC) above about 1.0 THz, the p-type guardring having a dimension which provides a cutoff frequency (FC) above about 1.0 THz, and a well tailor with an n-type dopant which provides a cutoff frequency (FC) above about 1.0 THz.
    Type: Grant
    Filed: February 16, 2011
    Date of Patent: November 26, 2013
    Assignee: International Business Machines Corporation
    Inventors: Jeffrey B. Johnson, Xuefeng Liu, Bradley A. Orner, Robert M. Rassel
  • Publication number: 20130309681
    Abstract: The present invention is directed towards methods of culturing non-keratinocyte epithelial cells, with the methods comprising culturing non-keratinocyte epithelial cells in the presence of feeder cells and a calcium-containing medium while inhibiting the activity of Rho kinase (ROCK) in the feeder cell, the non-keratinocyte epithelial cells or both during culturing.
    Type: Application
    Filed: November 11, 2011
    Publication date: November 21, 2013
    Applicant: Georgetown University
    Inventors: Richard Schlegel, Xuefeng Liu
  • Patent number: 8589832
    Abstract: An electromagnetic shielding structure that includes a conductive structure surrounding and accommodating a circuit or a circuit device arranged on a substrate. At least one feed through device is associated with the conductive structure and provides signals to the circuit or circuit device. The method includes forming a shielding structure so that the shielding structure at least one of is at least partially arranged within the substrate and surrounds the circuit or circuit device and associating at least one feed through device with the shielding structure.
    Type: Grant
    Filed: August 24, 2007
    Date of Patent: November 19, 2013
    Assignee: International Business Machines Corporation
    Inventors: Hanyi Ding, Kai D. Feng, Zhong-Xiang He, Xuefeng Liu
  • Publication number: 20130282340
    Abstract: Systems and methods for process aware metrology are provided. One method includes selecting nominal values and one or more different values of process parameters for one or more process steps used to form the structure on the wafer, simulating one or more characteristics of the structure that would be formed on the wafer using the nominal values, and determining parameterization of the optical model based on how the one or more characteristics of the structure vary between at least two of the nominal values and the one or more different values.
    Type: Application
    Filed: June 17, 2013
    Publication date: October 24, 2013
    Inventors: Xuefeng Liu, Yung-Ho Alex Chuang, John Fielden, Bin-Ming Benjamin Tsai, Jingjing Zhang
  • Patent number: 8566759
    Abstract: A design structure is embodied in a machine readable medium for designing, manufacturing, or testing an integrated circuit. The design structure comprises: a conductive structure surrounding and accommodating a circuit or a circuit device arranged on a substrate and at least one feed through capacitor and one transmission line associated with the conductive structure and providing the power supply and signals to the circuit or circuit device respectively. The design structure also comprises a shielding structure surrounding a circuit or a circuit device arranged on a substrate and at least one feed through capacitor or a transmission line arranged on a side of the shielding structure.
    Type: Grant
    Filed: March 12, 2008
    Date of Patent: October 22, 2013
    Assignee: International Business Machines Corporation
    Inventors: Hanyi Ding, Kai D. Feng, Zhong-Xiang He, Xuefeng Liu
  • Patent number: 8519892
    Abstract: A semiconductor chip integrating a transceiver, an antenna, and a receiver is provided. The transceiver is located on a front side of a semiconductor substrate. A through substrate via provides electrical connection between the transceiver and the receiver located on a backside of the semiconductor substrate. The antenna connected to the transceiver is located in a dielectric layer located on the front side of the substrate. The separation between the reflector plate and the antenna is about the quarter wavelength of millimeter waves, which enhances radiation efficiency of the antenna. An array of through substrate dielectric vias may be employed to reduce the effective dielectric constant of the material between the antenna and the reflector plate, thereby reducing the wavelength of the millimeter wave and enhance the radiation efficiency. A design structure for designing, manufacturing, or testing a design for such a semiconductor chip is also provided.
    Type: Grant
    Filed: June 27, 2012
    Date of Patent: August 27, 2013
    Assignee: International Business Machines Corporation
    Inventors: Hanyi Ding, Kai D. Feng, Zhong-Xiang He, Zhenrong Jin, Xuefeng Liu
  • Publication number: 20130187198
    Abstract: A heterojunction bipolar transistor (HBT) structure, method of manufacturing the same and design structure thereof are provided. The HBT structure includes a semiconductor substrate having a sub-collector region therein. The HBT structure further includes a collector region overlying a portion of the sub-collector region. The HBT structure further includes an intrinsic base layer overlying at least a portion of the collector region. The HBT structure further includes an extrinsic base layer adjacent to and electrically connected to the intrinsic base layer. The HBT structure further includes an isolation region extending vertically between the extrinsic base layer and the sub-collector region. The HBT structure further includes an emitter overlying a portion of the intrinsic base layer. The HBT structure further includes a collector contact electrically connected to the sub-collector region. The collector contact advantageously extends through at least a portion of the extrinsic base layer.
    Type: Application
    Filed: January 25, 2012
    Publication date: July 25, 2013
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Renata Camillo-Castillo, Zhong-Xiang He, Jeffrey B. Johnson, Qizhi Liu, Xuefeng Liu
  • Patent number: 8481380
    Abstract: A junction gate field-effect transistor (JFET) for an integrated circuit (IC) chip is provided comprising a source region, a drain region, a lower gate, and a channel, with an insulating shallow trench isolation (STI) region extending from an inner edge of an upper surface of the source region to an inner edge of an upper surface of the drain region, without an intentionally doped region, e.g., an upper gate, coplanar with an upper surface of the IC chip between the source/drain regions. In addition, an asymmetrical quasi-buried upper gate can be included, disposed under a portion of the STI region, but not extending under a portion of the STI region proximate to the drain region. Embodiments of this invention also include providing an implantation layer, under the source region, to reduce Ron. A related method and design structure are also disclosed.
    Type: Grant
    Filed: September 23, 2010
    Date of Patent: July 9, 2013
    Assignee: International Business Machines Corporation
    Inventors: Xuefeng Liu, Richard A. Phelps, Robert M. Rassel, Xiaowei Tian