Patents by Inventor Sunil D. Mehta

Sunil D. Mehta 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: 6197638
    Abstract: A method of providing oxide layers at the surface of the semiconductor substrate suitable for use with the formation of programmable logic devices. The method comprises the steps of: depositing a layer of nitride on the surface of the semiconductor substrate; etching a first and second portions of the nitride layer; forming a first and second regions of a first oxide layer on the substrate in the first and second etched portions of the nitride layer; etching a the first region of the oxide; forming a second oxide layer on the substrate having a first portion in the first etched portion of the nitride and a second portion overlying the first portion of the second region of the first oxide layer; removing the nitride layer; and forming a third layer of oxide having a first portion on the surface of the substrate, a second and third portions on the first and second portions of the second oxide layer.
    Type: Grant
    Filed: January 8, 1999
    Date of Patent: March 6, 2001
    Assignee: Vantis Corporation
    Inventor: Sunil D. Mehta
  • Patent number: 6184105
    Abstract: A method of fabricating integrated circuit including field effect transistors (FET) having source and drain regions and a gate and with LOCOS isolation by selectively forming, after the FETs are fabricated, trench openings in the source or drain regions or in the LOCOS isolation to maximize the isolation in selected areas while reducing the amount of silicon used by the isolation.
    Type: Grant
    Filed: May 22, 1997
    Date of Patent: February 6, 2001
    Assignee: Advanced Micro Devices
    Inventors: Yowjuang W. Liu, Sunil D. Mehta
  • Patent number: 6172392
    Abstract: A nonvolatile memory device utilizing a program junction region of a p-type impurity and oxide grown thereon. In one aspect, the device comprises a programming structure and a program junction separated from said programming structure by a field oxide region. A program junction oxide layer overlies said program junction region. A floating gate is provided over the oxide which covers said programming structure, said program junction oxide layer, and in some embodiments the gate oxide of a sense transistor.
    Type: Grant
    Filed: March 29, 1999
    Date of Patent: January 9, 2001
    Assignee: Vantis Corporation
    Inventors: Christopher O. Schmidt, Sunil D. Mehta, Xiao-Yu Li
  • Patent number: 6166428
    Abstract: A semiconductor device having at least a first and second type of devices formed in the substrate of the semiconductor device and having a hydrogen free barrier layer formed by implanting nitrogen into a layer of amorphous silicon or polysilicon formed on the surface of the semiconductor device. A hydrogen getter layer is formed on the semiconductor device under the barrier layer. The hydrogen getter layer is removed from portions of the semiconductor device on which salicide layers are to be formed.
    Type: Grant
    Filed: August 25, 1997
    Date of Patent: December 26, 2000
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Sunil D. Mehta, William G. En, Darin Arthur Chan, Raymond Takling Lee
  • Patent number: 6097090
    Abstract: Vias are formed by depositing a hard dielectric mask layer on the upper surface of a lower metal feature and forming sidewall spacers on the side surfaces of the metal feature and mask layer. Embodiments include depositing a dielectric interlayer and forming a misaligned through-hole therein by etching. The dielectric material of the sidewall spacer and dielectric material of the dielectric interlayer are different. The etchant employed to form the through-hole exhibits a high selectivity with respect to the sidewall spacer material. The dielectric mask layer enables the formation of a sidewall spacer extending above the metal feature such that, after etching to form the misaligned through-hole, the sidewall spacer covers the side surface of the metal feature.
    Type: Grant
    Filed: June 23, 1998
    Date of Patent: August 1, 2000
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Khanh Q. Tran, Sunil D. Mehta, Andre Stolmeijer
  • Patent number: 6093946
    Abstract: An improved EEPROM cell having a field-edgeless tunnel window is provided which is fabricated by a STI process so as to produce reliable endurance and data retention. The EEPROM cell includes a floating gate, a programmable junction region, and a tunneling oxide layer separating the programmable junction region and the floating gate. The tunneling oxide layer defines a tunnel window which allows for programming and erasing of the floating gate by tunneling electrons therethrough. The programmable junction region has a width dimension and a length dimension so as to define a first area. The tunnel window has a width dimension and a length dimension so as to define a second area. The second area of the tunnel window is completely confined within the first area of the programmable junction region so as to form a field-edgeless tunnel window.
    Type: Grant
    Filed: February 20, 1998
    Date of Patent: July 25, 2000
    Assignee: Vantis Corporation
    Inventors: Xiao-Yu Li, Sunil D. Mehta
  • 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: 6087275
    Abstract: A method of manufacturing a semiconductor device with increasing threshold voltage for parasitic transistor by forming a low power-low pressure phosphosilicate glass layer on the active regions and the field oxide regions.
    Type: Grant
    Filed: April 26, 1997
    Date of Patent: July 11, 2000
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Minh Van Ngo, Sunil D. Mehta, Nicholas R. MacCrae
  • 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: 6071784
    Abstract: This invention includes a semiconductor device having a gate formed on a semiconductor substrate with a low hydrogen content etch stop or barrier layer formed over the gate, and methods for manufacturing a semiconductor device with an etch stop or barrier layer with low free hydrogen content. The semiconductor device may have a hydrogen getter layer formed between the gate and the etch stop or barrier layer. The etch stop or barrier layer is a high temperature PECVD nitride film, a high temperature PECVD oxynitride film or a high temperature LPCVD nitride film. The hydrogen getter layer is P-doped film having a thickness between about 500 .ANG. and about 2000 .ANG. and is a PSG, BPSG, PTEOS deposited oxide film, or a BPTEOS deposited oxide film. The low free hydrogen content of the etch stop layer or barrier layer is achieved by a high temperature annealing step, performed at a higher temperature than the deposition temperature of the etch stop or barrier layer.
    Type: Grant
    Filed: August 29, 1997
    Date of Patent: June 6, 2000
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Sunil D. Mehta, Radu Barsan
  • 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: 6064595
    Abstract: A method of creating a reverse breakdown condition in an array of memory cells arranged in columns and rows in the array, and an array structure are provided. The method comprises the steps of applying a first voltage on a first column connection coupling a first column of said cells, and a second voltage on a second column connection coupling a second column of said cells; and applying a third voltage on a first row connection coupling a first row of said cells, and applying said second voltage on a second row connection coupling a second row of said cells. In this aspect, the difference between the first voltage and the third voltage creates said reverse breakdown condition in at least one cell occupying said first column and first row. In a further aspect, each cell includes a floating gate and the method of the invention includes the step of programming one of said cells by coupling a control voltage to each floating gate.
    Type: Grant
    Filed: December 23, 1998
    Date of Patent: May 16, 2000
    Assignee: Vantis Corporation
    Inventors: Stewart G. Logie, Sunil D. Mehta, Steven J. Fong
  • Patent number: 6060766
    Abstract: A semiconductor device with first and second types of devices formed in a semiconductor substrate with a barrier layer formed over the surface of the semiconductor device including over the first and second types of devices with the barrier layer removed from over the first type of device. The first type of device is a positive charge sensitive device such as a nonvolatile memory device. The semiconductor device has a hydrogen getter layer formed under the barrier layer.
    Type: Grant
    Filed: August 25, 1997
    Date of Patent: May 9, 2000
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Sunil D. Mehta, William G. En
  • 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: 6034893
    Abstract: A non-volatile memory cell includes a well region formed in a semiconductor substrate. First and second avalanche injection elements reside in the well region. A bifurcated floating-gate electrode includes a first segment overlying the first avalanche injection element and a second segment overlying the second avalanche injection element. A first contact region resides in the well region adjacent to the first segment of the floating-gate electrode, and a second contact region resides in the well region adjacent to the second segment of the floating-gate electrode. Upon the application of programming or erasing voltage, electrical charge is independently transferred to each of the first and second segments of the floating-gate electrode from the first and second avalanche injection elements, respectively.
    Type: Grant
    Filed: June 15, 1999
    Date of Patent: March 7, 2000
    Assignee: Vantis Corporation
    Inventor: Sunil D. Mehta
  • Patent number: 6028789
    Abstract: A zero-power non-volatile memory cell includes a control element, an avalanche injection element, and a CMOS inverter. A floating-gate electrode is capacitively coupled to the control element, the avalanche injection element, and to the CMOS inverter. The avalanche injection element is arranged, so as to transfer electrical charge onto the floating-gate electrode. The presence of stored data within the memory cell is indicated by reading a supply voltage V.sub.DD at an output terminal of the inverter. Accordingly, data can be read from the non-volatile memory cell without applying electrical power to the cell.
    Type: Grant
    Filed: June 15, 1999
    Date of Patent: February 22, 2000
    Assignee: Vantis Corporation
    Inventors: Sunil D. Mehta, Brad Sharpe-Geisler, Steven Fong
  • Patent number: 6025637
    Abstract: The present antifuse includes a base having a first electrode thereon which defines a top surface and a side surface. Antifuse material is disposed on the first electrode on at least a portion of the top surface and at least a portion of the side surface, with a second electrode on the antifuse material. Due to this configuration, defect problems in etching oxide as part of the antifuse structure are avoided, and meanwhile capacitance of the device is very low.
    Type: Grant
    Filed: February 10, 1998
    Date of Patent: February 15, 2000
    Assignee: Advanced Micro Devices, Inc.
    Inventor: 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