Patents by Inventor Xia Li

Xia 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: 20190305094
    Abstract: In certain aspects, a heterojunction bipolar transistor (HBT) comprises a collector mesa, a base mesa on the collector mesa, and an emitter mesa on the base mesa. The base mesa has a tapered sidewall tapering from a wide bottom to a narrow top. The HBT further comprises a collector contact on a portion of the collector mesa and extending to a portion of the tapered sidewall of the base mesa.
    Type: Application
    Filed: March 27, 2018
    Publication date: October 3, 2019
    Inventors: Gengming TAO, Bin YANG, Xia LI
  • Publication number: 20190305971
    Abstract: Physically unclonable function (PUF) memory employing static random access memory (SRAM) bit cells enhanced by stress for increased PUF output reproducibility. Stress voltage applied to SRAM bit cells enhances their skew so that the SRAM bit cells output their preferred initial state in subsequent PUF read operations regardless of process variation and other external environmental variations, such as temperature. The application of stress voltage on the SRAM bit cells in a PUF memory array takes advantage of the recognition of aging effect in transistors, where turning transistors on and off over time can increase threshold voltage resulting in lower drive current. Stress voltage can be applied to the SRAM bit cells to bias their threshold voltage to simulate this aging effect to enhance mismatch between transistors in the SRAM bit cell to more fully skew the SRAM bit cells for increased PUF output reproducibility with less susceptible to noise.
    Type: Application
    Filed: April 3, 2018
    Publication date: October 3, 2019
    Inventors: Xia Li, Xiao Lu, Seung Hyuk Kang
  • Patent number: 10431581
    Abstract: Certain aspects of the present disclosure provide a semiconductor device. One example semiconductor device generally includes a substrate, a well region disposed adjacent to the substrate, a first fin disposed above the well region, a second fin disposed above the substrate, and a gate region disposed adjacent to each of the first fin and the second fin. The semiconductor device may also include at least one third fin disposed above the substrate, a support layer disposed above the at least one third fin, and a compound semiconductor device disposed above the support layer.
    Type: Grant
    Filed: April 30, 2018
    Date of Patent: October 1, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Xia Li, Gengming Tao, Bin Yang
  • Patent number: 10431278
    Abstract: Dynamically controlling voltage for access operations to magneto-resistive random access memory (MRAM) bit cells to account for ambient temperature is disclosed. An MRAM bit cell process variation measurement circuit (PVMC) is configured to measure process variations and ambient temperature in magnetic tunnel junctions (MTJs) that affect MTJ resistance, which can change the write current at a given fixed supply voltage applied to an MRAM bit cell. These measured process variations and ambient temperature are used to dynamically control a supply voltage for access operations to the MRAM to reduce the likelihood of bit errors and reduce power consumption. The MRAM bit cell PVMC may also be configured to measure process variations and/or ambient temperatures in logic circuits that represent the process variations and ambient temperatures in access transistors employed in MRAM bit cells in the MRAM to determine variations in the switching speed (i.e., drive strength) of the access transistors.
    Type: Grant
    Filed: August 14, 2017
    Date of Patent: October 1, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Xia Li, Wah Nam Hsu, Wei-Chuan Chen, Seung Hyuk Kang
  • Patent number: 10424380
    Abstract: Physically unclonable function (PUF) memory employing static random access memory (SRAM) bit cells with added passive resistance are disclosed. Added passive resistance can enhance imbalance between transistors in the SRAM bit cell for improved PUF output reproducibility. Enhancing transistor imbalance can more fully skew the SRAM bit cell for increased PUF output reproducibility while still achieving the benefits of output randomness. In one exemplary aspect, added passive resistances in the SRAM bit cell are coupled to a drain of one or more pull-down N-type FETs (NFETs)) in one or more cross-coupled inverters in the SRAM bit cell to enhance imbalance between the inverters. Enhanced imbalance between the inverters increases sensitivity in the output voltage of the SRAM bit cell for a given change in input voltage resulting in greater skew of the SRAM bit cell for increased reproducibility.
    Type: Grant
    Filed: June 15, 2018
    Date of Patent: September 24, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Xia Li, Jianguo Yao, Seung Hyuk Kang
  • Publication number: 20190288662
    Abstract: A surface acoustic wave (SAW) device comprises a substrate and composite electrodes. The composite electrodes comprise a metal layer and a graphene layer. The SAW device may be used to satisfy requirements for the fifth generation (5G) mobile communication.
    Type: Application
    Filed: March 15, 2018
    Publication date: September 19, 2019
    Inventors: Bin Yang, Xia Li, Gengming Tao, Periannan Chidambaram
  • Patent number: 10410714
    Abstract: Multi-level cell (MLC) static random access memory (SRAM) (MLC SRAM) cells configured to perform multiplication operations are disclosed. In one aspect, an MLC SRAM cell includes SRAM bit cells, wherein data values stored in SRAM bit cells correspond to a multiple-bit value stored in the MLC SRAM cell that serves as first operand in multiplication operation. Voltage applied to read bit line is applied to each SRAM bit cell, wherein the voltage is an analog representation of a multiple-bit value that serves as a second operand in the multiplication operation. For each SRAM bit cell, if a particular binary data value is stored, a current correlating to the voltage of the read bit line is added to a current sum line. A magnitude of current on the current sum line is an analog representation of a multiple-bit product of the first operand multiplied by the second operand.
    Type: Grant
    Filed: September 20, 2017
    Date of Patent: September 10, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Xia Li, Seung Hyuk Kang, Venkat Rangan, Rashid Ahmed Akbar Attar, Nicholas Ka Ming Stevens-Yu
  • Publication number: 20190265142
    Abstract: A method for obtaining a conversion relationship between dynamic and static elastic parameters includes: Step S1, acquiring horizontal cores at different depths of the destination formation; Step S2, measuring the dynamic elastic parameters of the horizontal core under different pressures; Step S3, measuring the static elastic parameters of the horizontal core under different pressures; Step S4, measuring the clay content of the horizontal core; Step S5 establishing a function relationship of the ratio between the dynamic and static elastic parameters with the formation pressure and clay content; and completing the conversion between the dynamic and static elastic parameters. The technical solution provided by the present invention takes full account of the influence of the formation stress and the clay content on the conversion rule of dynamic and static elastic parameters and is of great significance for improving the logging evaluation accuracy of rock mechanical parameters.
    Type: Application
    Filed: April 19, 2017
    Publication date: August 29, 2019
    Inventors: Zhonghua Liu, Lianteng Song, Haitao Zhang, Jixin Deng, Xia Li, Chao Yuan, Xiaoming Yang, Xiangzhi Cheng
  • Patent number: 10396188
    Abstract: A semiconductor device comprises a heterojunction bipolar transistor (HBT). The HBT comprises an emitter, a collector, and a base between the emitter and the collector. A width of the emitter may be smaller than 100 nanometers, which is suitable for high speed applications.
    Type: Grant
    Filed: April 25, 2018
    Date of Patent: August 27, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Bin Yang, Gengming Tao, Xia Li
  • Publication number: 20190245058
    Abstract: A heterojunction bipolar transistor may include an emitter, a base contacting the emitter, a collector contacting the base, a sub-collector contacting the collector, and an electrical isolation layer contacting the sub-collector. The heterojunction bipolar transistor may also include a backside heatsink thermally coupled to the sub-collector and the collector. The backside heatsink may be aligned with a central axis of the emitter and the base.
    Type: Application
    Filed: April 15, 2019
    Publication date: August 8, 2019
    Inventors: Bin YANG, Gengming TAO, Xia LI
  • Publication number: 20190229933
    Abstract: In certain aspects, an apparatus comprises a plurality of PUF cells. Each PUF cell comprises a first transistor in series with a first loading resistive component and coupled to a common cross-coupled node and cross-coupled to a complementary common cross-coupled node, a second transistor in series with a second loading resistive component and coupled to the complementary common cross-coupled node and cross-coupled to the common cross-coupled node, a first pass-gate and a second pass-gate coupled to a bit line and the complementary bit line, respectively. The apparatus further comprises an auxiliary peripheral circuit coupled to the bit line, the complementary bit line, the common cross-coupled node, and the complementary common cross-coupled node. During activation, the selected PUF cell, together with the auxiliary peripheral circuit, forms a cross-coupled inverter pair and outputs a physical unclonable function value.
    Type: Application
    Filed: January 23, 2018
    Publication date: July 25, 2019
    Inventors: Xia LI, Seung Hyuk KANG, Bin YANG, Gengming TAO
  • Publication number: 20190214554
    Abstract: Double-patterned magneto-resistive random access memory (MRAM) for reducing magnetic tunnel junction (MTJ) pitch for increased MRAM bit cell density is disclosed. In one aspect, to fabricate MTJs in an MRAM array with reduced MTJ row pitch, a first patterning process is performed to provide separation areas in an MTJ layer between what will become rows of fabricated MTJs, which facilitates MTJs in a given row sharing a common bottom electrode. This reduces the etch depth and etching time needed to etch the individual MTJs in a subsequent step, can reduce lateral projections of sidewalls of the MTJs, thereby relaxing the pitch between adjacent MTJs, and may allow an initial MTJ hard mask layer to be reduced in height. A subsequent second patterning process is performed to fabricate individual MTJs. Additional separation areas are etched between free layers of adjacent MTJs in a given row to fabricate the individual MTJs.
    Type: Application
    Filed: January 11, 2018
    Publication date: July 11, 2019
    Inventors: Xia Li, Wei-Chuan Chen
  • Patent number: 10347821
    Abstract: A method includes patterning a photo resist layer on top of a semiconductor device. The semiconductor device includes a lower portion, a capping layer formed on top of the lower portion, and an optional oxide layer formed on top of the capping layer. The lower portion includes a dielectric material and an interconnect. The method also includes etching portions of the semiconductor device based on the photo resist layer to expose the interconnect. The method further includes depositing a bottom electrode of a resistive memory device on the interconnect. The bottom electrode is comprised of cobalt tungsten phosphorus (CoWP).
    Type: Grant
    Filed: November 21, 2017
    Date of Patent: July 9, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Yu Lu, Junjing Bao, Xia Li, Seung Hyuk Kang
  • Patent number: 10340395
    Abstract: Certain aspects of the present disclosure generally relate to a semiconductor variable capacitor, and techniques for fabricating the same, implemented using a threshold voltage implant region. For example, the semiconductor variable capacitor generally includes a first non-insulative region disposed above a first semiconductor region, a second non-insulative region disposed above the first semiconductor region, and a threshold voltage (Vt) implant region interposed between the first non-insulative region and the first semiconductor region and disposed adjacent to the second non-insulative region. In certain aspects, the semiconductor variable capacitor also includes a control region disposed above the first semiconductor region such that a capacitance between the first non-insulative region and the second non-insulative region is configured to be adjusted by varying a control voltage applied to the control region.
    Type: Grant
    Filed: May 1, 2017
    Date of Patent: July 2, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Xia Li, Fabio Alessio Marino, Qingqing Liang, Francesco Carobolante, Seung Hyuk Kang
  • Patent number: 10332590
    Abstract: Static random access memory (SRAM) bit cells employing current mirror-gated read ports for reduced power consumption are disclosed. In one aspect, an SRAM bit cell includes a read port employing a first transistor electrically coupled to a current sum line and to a current mirror circuit. A level of current that flows through the first transistor in response to voltage applied by the current mirror circuit correlates to a magnitude of the voltage. The read port includes a second transistor electrically coupled to the first transistor, to a driver circuit, and to an output node of a first inverter. Connecting the first and second transistors of the read port in this manner allows a voltage applied to the second transistor to generate a current that flows to the first transistor if the second transistor is activated. The current level depends on the voltage applied by the current mirror circuit.
    Type: Grant
    Filed: September 21, 2017
    Date of Patent: June 25, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Xia Li, Jianguo Yao
  • Publication number: 20190189787
    Abstract: A heterojunction bipolar transistor (HBT) may include a base contact and emitter mesas on a collector mesa. The HBT may include emitter contacts on the emitter mesas. The HBT may include a first dielectric layer on the collector mesa, sidewalls of the emitter mesas, and the base contact. The HBT may further include a second dielectric layer on the first dielectric layer and on sidewalls of the emitter contacts. The HBT may further include a secondary conductive layer on the first dielectric layer, the second dielectric layer, and the emitter contacts.
    Type: Application
    Filed: May 21, 2018
    Publication date: June 20, 2019
    Inventors: Gengming TAO, Xia LI, Bin YANG
  • Patent number: 10319830
    Abstract: A heterojunction bipolar transistor may include an emitter, a base contacting the emitter, a collector contacting the base, a sub-collector contacting the collector, and an electrical isolation layer contacting the sub-collector. The heterojunction bipolar transistor may also include a backside heatsink thermally coupled to the sub-collector and the collector. The backside heatsink may be aligned with a central axis of the emitter and the base.
    Type: Grant
    Filed: May 17, 2017
    Date of Patent: June 11, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Bin Yang, Gengming Tao, Xia Li
  • Patent number: 10312244
    Abstract: Bi-stable static random access memory (SRAM) bit cells that facilitate direct writing for storage are disclosed. In one aspect, a bi-stable SRAM bit cell includes source and drain regions, and a gate region formed over a well region between the source and drain regions, which results in two (2) bipolar junction transistors (BJTs) formed within a bi-stable SRAM bit cell. A base tap region and a collector tap region are employed to provide voltages for read and write operations. The base tap region is formed beside a shallow trench isolation (STI) region having a bottom surface higher in a Y-axis direction in the well region than a bottom surface of the well region. The collector tap region is formed on one side of an STI region having a bottom surface lower in the Y-axis direction in the substrate than the bottom surface of the well region.
    Type: Grant
    Filed: September 19, 2017
    Date of Patent: June 4, 2019
    Assignee: QUALCOMM Incorporated
    Inventors: Xia Li, Seung Hyuk Kang, Bin Yang, Gengming Tao
  • Publication number: 20190163864
    Abstract: A method, system, and computer program product for enhancing integrated circuit noise performance. The method is for arranging target wires in a target region, the method including: for each wire in the target wires, obtaining a signal jump interval with respect to each of the other wires in the target wires, wherein the signal jump interval of one wire with respect to a further wire is a time interval between occurrence of signal jump on the one wire and occurrence of signal jump on the further wire; calculating a corresponding time influence factor based on the signal jump interval, wherein the time influence factor is a decreasing function of the signal jump interval; and arranging the target wires in the target region based on the time influence factor. Coupling noise between wires may be reduced according to the technical solution of an embodiment of the present invention.
    Type: Application
    Filed: February 1, 2019
    Publication date: May 30, 2019
    Inventors: Xia Li, Suo Ming Pu, Xiao Feng Tang, Bo Yu
  • Publication number: 20190163865
    Abstract: A method, system, and computer program product for enhancing integrated circuit noise performance. The method is for arranging target wires in a target region, the method including: for each wire in the target wires, obtaining a signal jump interval with respect to each of the other wires in the target wires, wherein the signal jump interval of one wire with respect to a further wire is a time interval between occurrence of signal jump on the one wire and occurrence of signal jump on the further wire; calculating a corresponding time influence factor based on the signal jump interval, wherein the time influence factor is a decreasing function of the signal jump interval; and arranging the target wires in the target region based on the time influence factor. Coupling noise between wires may be reduced according to the technical solution of an embodiment of the present invention.
    Type: Application
    Filed: February 1, 2019
    Publication date: May 30, 2019
    Inventors: Xia Li, Suo Ming Pu, Xiao Feng Tang, Bo Yu