Patents by Inventor Xiao-Yu Li

Xiao-Yu 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: 6087696
    Abstract: An improved EEPROM cell structure and a method of fabricating the same is provided so as to improve data retention. The EEPROM cell includes a stacked dielectric structure consisting of a thin tunnel oxide layer and a high-k dielectric layer to function as the tunneling dielectric barrier so as to suppress leakage current.
    Type: Grant
    Filed: May 28, 1998
    Date of Patent: July 11, 2000
    Assignee: Lattice Semiconductor Corp.
    Inventors: Xiao-Yu Li, Qi Xiang, Sunil D. Mehta
  • Patent number: 6075293
    Abstract: A multi-level metal interconnect structure in a semiconductor device includes a plurality of overlying metal layers separated by ILD layers and electrically connected by filled vias in the ILD layers. Each metal layer includes a relatively thick antireflective layer for improved electromigration resistance. Each metal layer also includes a metal lining layer and a metal interconnect layer overlying the metal lining layer. Enhanced electromigration resistance is obtained by forming the antireflective layer to a thickness of no less than the thickness of the metal lining layer. In a preferred embodiment of the invention, the antireflective layer has a thickness of about 1000 angstroms.
    Type: Grant
    Filed: March 5, 1999
    Date of Patent: June 13, 2000
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Xiao-Yu Li, Sunil D. Mehta, Van H. Pham, Amit P. Marathe
  • Patent number: 6075724
    Abstract: A method for sorting semiconductor devices having a plurality of non-volatile memory cells effectively screens memory cells with a predicted lifetime less than a desired lifetime, in part, by determining a minimum acceptable voltage value and a maximum acceptable voltage drop value for each cell in the device at a margin sort read point. In the method of the invention, the device is first stressed by programming and erasing the memory cells for a predetermined number of cycles. After stressing the device, the device is erased and an initial voltage across a floating-gate is measured at time=0. The initial voltage value is compared with acceptable minimum and maximum initial voltages. The device is discarded if the initial voltage value is outside of the range defined by the minimum and maximum initial voltages. Next, the device is baked at a predetermined temperature. Then, a voltage drop value is determined by measuring a second voltage on the floating-gate at the margin sort read point.
    Type: Grant
    Filed: February 22, 1999
    Date of Patent: June 13, 2000
    Assignee: Vantis Corporation
    Inventors: Xiao-Yu Li, Sunil D. Mehta
  • Patent number: 6064105
    Abstract: A shallow trench isolation structure and a method for forming the same for use with non-volatile memory devices is provided so as to maintain sufficient data retention thereof. An epitaxial layer is formed on a top surface of a semiconductor substrate. A barrier oxide layer is formed on a top surface of the epitaxial layer. A nitride layer is deposited on a top surface of the barrier oxide layer. Trenches are formed through the epitaxial layer and the barrier oxide layer to a depth greater than 4000 .ANG. below the surface of the epitaxial layer so as to create isolation regions in order to electrically isolate active regions in the epitaxial layer. A liner oxide is formed on sidewalls and bottom of the trenches to a thickness between 750 .ANG. to 1500 .ANG.. As a result, leakage current in the sidewalls are prevented due to less thinning of the liner oxide layer by subsequent fabrication process steps.
    Type: Grant
    Filed: August 14, 1998
    Date of Patent: May 16, 2000
    Assignee: Vantis Corporation
    Inventors: Xiao-Yu Li, Radu Barsan, Sunil D. Mehta
  • Patent number: 6040019
    Abstract: A method of forming a region of impurity in a semiconductor substrate with minimal damage. The method includes the steps of: forming a reaction-inhibiting impurity region in the semiconductor substrate to a depth below the semiconductor substrate; and applying laser energy to the semiconductor substrate at a sufficient magnitude to liquify the semiconductor substrate in the region.
    Type: Grant
    Filed: February 14, 1997
    Date of Patent: March 21, 2000
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Emi Ishida, Xiao-Yu Li, Sunil D. Mehta
  • Patent number: 6009033
    Abstract: A semiconductor device having an EEPROM array includes resistive elements capable of elevating the temperature of the EEPROM array during programming and erasing operations. The resistive elements are located in close proximity to individual EEPROM cells within an EEPROM array. By elevating the temperature of the EEPROM cell during programming and erasing operations, data errors associated with shifting threshold voltages of floating-gate devices within the EEPROM is reduced. An operating method for improving the long term reliability of an EEPROM device includes the step of providing thermal energy during programming and erasing sufficient to raise the temperature of the EEPROM device to at least about 70.degree. C.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: December 28, 1999
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Xiao-Yu Li, Sunil D. Mehta
  • Patent number: 5999449
    Abstract: A two transistor EEPROM cell is described that is programmed and erased by electron tunneling across a tunneling channel in a P-well. The EEPROM cell has two transistors formed in a semiconductor substrate. The two transistors are a tunneling transistor (NMOS) and a read transistor (NMOS).
    Type: Grant
    Filed: January 27, 1999
    Date of Patent: December 7, 1999
    Assignee: Vantis Corporation
    Inventors: Sunil D. Mehta, Xiao-Yu Li
  • Patent number: 5969992
    Abstract: An EEPROM cell is described that is programmed and erased by electron tunneling across an entire portion of separate transistor channels. The EEPROM cell has three transistors formed in a P-well of a semiconductor substrate. The three transistors are a tunneling transistor (NMOS), a sense transistor (NMOS) and a read transistor (NMOS). Electron tunneling occurs to program the EEPROM cell through a sense tunnel oxide layer upon incurrence of a sufficient voltage potential between a floating gate and the sense channel. Electron tunneling also occurs to erase the EEPROM cell through a tunnel oxide layer upon incurrence of a sufficient voltage potential between the floating gate and the tunneling channel.
    Type: Grant
    Filed: December 21, 1998
    Date of Patent: October 19, 1999
    Assignee: Vantis Corporation
    Inventors: Sunil D. Mehta, Xiao-Yu Li
  • Patent number: 5942780
    Abstract: An integrated circuit ("IC") having three different oxide layer thicknesses and a process for manufacturing the IC using a single oxide growth step is provided. A first region is formed on a substrate surface with oxidation enhancing properties. A second region is formed on the substrate surface with a dose of nitrogen that retards oxidation. An oxide layer is grown from the first and the second regions and a third region of the substrate such that the first, second, and third regions yield a first oxide layer for the capacitor, a second oxide layer for the read transistor and a third oxide layer for the write transistor.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: August 24, 1999
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Radu M. Barsan, Xiao-Yu Li, Sunil Mehta
  • Patent number: 5904575
    Abstract: A method for forming an oxide on the surface of a semiconductor substrate. The method includes the steps of: placing the semiconductor substrate in an atmosphere containing an atmosphere of an oxide growth inhibiting compound; applying laser energy to at least a first portion of the substrate; and forming the oxide on the surface of the substrate by heating the substrate. In a further aspect of the invention, the method comprises applying laser energy through a patterned, reflective reticle. Alternatively, prior to the step of placing, a reflective mask layer may be applied to the surface of the semiconductor substrate. In addition, the invention comprises an EEPROM memory cell having a program junction region in a semiconductor substrate. The cell comprises at least a first program junction provided in the silicon substrate and a floating gate having a portion positioned over the program junction.
    Type: Grant
    Filed: February 14, 1997
    Date of Patent: May 18, 1999
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Emi Ishida, Xiao-Yu Li, Sunil D. Mehta
  • Patent number: 5885904
    Abstract: A method for forming a uniform and reliable oxide layer on the surface of a semiconductor substrate using projection gas immersion laser doping (P-GILD) is provided. A semiconductor substrate is immersed in an oxide enhancing compound containing atmosphere. The oxide enhancing compound containing atmosphere may include phosphorus, arsenic, boron or an equivalent. A 308 nm excimer laser is then applied to a portion of the substrate to induce incorporation of the oxide enhancing compound into a portion of the substrate. The deposition depth is dependent upon the strength of the laser energy directed at the surface of the substrate. A uniform and reliable oxide layer is then formed on the surface of the substrate by heating the substrate. The laser may be applied with a reflective reticle or mask formed on the substrate. An E.sup.2 PROM memory cell having a program junction region in a silicon substrate is also provided. An oxide layer is positioned between a program junction and a floating gate.
    Type: Grant
    Filed: February 14, 1997
    Date of Patent: March 23, 1999
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Sunil Mehta, Emi Ishida, Xiao-Yu Li
  • Patent number: 5854114
    Abstract: A shallow trench isolation structure and a method for forming the same for use with non-volatile memory devices is provided so as to maintain sufficient data retention thereof. An epitaxial layer is formed on a top surface of a semiconductor substrate. A barrier oxide layer is formed on a top surface of the epitaxial layer. A nitride layer is deposited on a top surface of the barrier oxide layer. Trenches are formed through the epitaxial layer and the barrier oxide layer to a depth greater than 4000 .ANG. below the surface of the epitaxial layer so as to create isolation regions in order to electrically isolate active regions in the epitaxial layer. A liner oxide is formed on sidewalls and bottom of the trenches to a thickness between 750 .ANG. to 1500 .ANG.. As a result, leakage current in the sidewalls are prevented due to less thinning of the liner oxide layer by subsequent fabrication process steps.
    Type: Grant
    Filed: October 9, 1997
    Date of Patent: December 29, 1998
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Xiao-Yu Li, Radu Barsan, Sunil D. Mehta
  • Patent number: 5841701
    Abstract: A method for improving the endurance and reliability of a floating gate transistor often used in memory applications by controlling the electric field induced across the tunnel oxide region of the floating gate when discharging electrons from the floating gate. The method comprises the steps of: allowing the active region to ground; and applying a program voltage to the floating gate over a period of time and at a magnitude, by increasing the voltage from zero volts to the magnitude over a first period of at least 1 millisecond (ms.), maintaining the voltage at the magnitude for a second period of around 10 ms.-100 ms. sufficient to place charge on the floating gate, and decreasing the voltage from the magnitude during a third period to zero volts in not greater than 50 microseconds.
    Type: Grant
    Filed: January 21, 1997
    Date of Patent: November 24, 1998
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Xiao-Yu Li, Radu Barsan, Sunil Mehta
  • Patent number: 5795627
    Abstract: A method of forming an oxide enhancing region, such as phosphorus, in a semiconductor substrate with minimal damage is provided. The method includes the steps of forming an oxide enhancing region in the semiconductor substrate to a depth below the semiconductor substrate. A 308 nm excimer laser is then applied to the oxide enhancing region in order to reduce the damage caused by forming the oxide enhancing region. A uniform and reliable oxide layer is then formed on the surface of the substrate over the damage reduced oxide enhancing region.
    Type: Grant
    Filed: February 14, 1997
    Date of Patent: August 18, 1998
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Sunil Mehta, Emi Ishida, Xiao-Yu Li
  • Patent number: 5761116
    Abstract: An enhanced, scalable EEPROM memory cell is provided with a structure having a plurality of half-height tunnel oxide depletion mode transistors. The structure further has individual wordlines controlling the write and read transistors, respectively. With such a structure, lower voltages are used to program/erase the memory cell. The memory cell is scalable to small dimensions through the use of transistors having half-height tunnel oxide regions.
    Type: Grant
    Filed: October 7, 1996
    Date of Patent: June 2, 1998
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Xiao-Yu Li, Radu Barsan
  • Patent number: 5672521
    Abstract: An integrated circuit device and manufacturing process wherein a first region is formed in a substrate with a dopant that enhances oxide formation and a second region is formed in the substrate with a dose of nitrogen that retards oxide formation. An oxide layer is grown over the first and the second regions and over a third region of the substrate such that the first, second, and third regions yield differing thicknesses of the oxide layer.
    Type: Grant
    Filed: November 21, 1995
    Date of Patent: September 30, 1997
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Radu M. Barsan, Xiao-Yu Li, Sunil Mehta