Patents by Inventor Aftab Ahmad

Aftab Ahmad 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: 6333539
    Abstract: In one aspect, the invention encompasses a transistor device comprising a region of a semiconductor material wafer, and a transistor gate over a portion of the region. The transistor gate has a pair of opposing sidewalls which are a first sidewall and a second sidewall. The device further comprises a pair of opposing sidewall spacers adjacent the sidewalls of the transistor gate and a pair of opposing first conductivity type source/drain regions within the semiconductor material wafer proximate the transistor gate. One of the sidewall spacers extends along the first sidewall of the gate and the other of the sidewall spacers extends along the second sidewall of the gate. The entirety of the semiconductor wafer material under one of the sidewall spacers being defined as a first segment of the semiconductor wafer material, and the entirety of the semiconductor wafer material which is under the other of the sidewall spacers being defined as a second segment of the semiconductor wafer material.
    Type: Grant
    Filed: October 6, 1998
    Date of Patent: December 25, 2001
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, David J. Keller
  • Patent number: 6326250
    Abstract: In one aspect of the invention, a semiconductor processing method includes: a) providing a semiconductor substrate; b) defining a first conductivity type region and a second conductivity type region of the semiconductor substrate; c) providing a first transistor gate over the first type region which defines a first source area and a first drain area operatively adjacent thereto; d) providing a second transistor gate over the second type region which defines a second source area and a second drain area operatively adjacent thereto; and e) blanket implanting a conductivity enhancing dopant of the second conductivity type through the first source and drain areas of the first conductivity region and the second source and drain areas of the second conductivity region to provide second conductivity type regular LDD implant regions within the substrate operatively adjacent the first transistor gate and to provide second conductivity type halo implant regions within the substrate operatively adjacent the second trans
    Type: Grant
    Filed: December 22, 1997
    Date of Patent: December 4, 2001
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, Kirk Prall
  • Patent number: 6319779
    Abstract: The invention includes a method for forming graded junction regions comprising: a) providing a semiconductor material wafer; b) providing a transistor gate over the semiconductor material wafer, the transistor gate having opposing lateral sidewalls; c) providing sidewall spacers adjacent the sidewalls of the transistor gate, the sidewall spacers having a lateral thickness; d) decreasing the lateral thickness of the sidewall spacers; and e) after decreasing the lateral thickness of the sidewall spacers, implanting a conductivity-enhancing dopant into the semiconductor material to form graded junction regions operatively adjacent the transistor gate.
    Type: Grant
    Filed: October 6, 1998
    Date of Patent: November 20, 2001
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, David J. Keller
  • Patent number: 6281092
    Abstract: A capacitor is fabricated on a semiconductor substrate by first forming a first capacitor electrode on the semiconductor substrate and forming a planar insulating layer over the first capacitor electrode. A photoresist layer is then formed over the planar insulating layer and patterned utilizing in only masking step to form an opening over the first capacitor electrode. Through the opening, the planar insulating layer is etched, and a capacitor dielectric layer is thereafter formed. A second capacitor electrode is then formed over the capacitor dielectric layer in alignment with the first capacitor electrode. The structure is planarized to expose the planar insulating layer. In a preferred embodiment, a trench in the second capacitor electrode is protected during planarization by a spin-on photoresist that is stripped following planarization.
    Type: Grant
    Filed: July 2, 1999
    Date of Patent: August 28, 2001
    Assignee: LSI Logic Corporation
    Inventor: Aftab Ahmad
  • Publication number: 20010009791
    Abstract: Methods of forming integrated circuitry, methods of forming elevated source/drain regions, and methods of forming field effect transistors are described. In one embodiment, a transistor gate line is formed over a semiconductive substrate. A layer comprising undoped semiconductive material is formed laterally proximate the transistor gate line and joins with semiconductive material of the substrate and comprises elevated source/drain material for a transistor of the line. Subsequently, conductivity-modifying impurity is provided into the elevated source/drain material. In another embodiment, a common step is utilized to provide conductivity enhancing impurity into both elevated source/drain material and material of the gate line. In another embodiment, the undoped semiconductive layer is first patterned and etched to provide elevated source/drain regions prior to provision of the conductivity-modifying impurity.
    Type: Application
    Filed: January 26, 2001
    Publication date: July 26, 2001
    Inventors: Aftab Ahmad, Lyle Jones
  • Patent number: 6211026
    Abstract: Methods of forming integrated circuitry, methods of forming elevated source/drain regions, and methods of forming field effect transistors are described. In one embodiment, a transistor gate line is formed over a semiconductive substrate. A layer comprising undoped semiconductive material is formed laterally proximate the transistor gate line and joins with semiconductive material of the substrate and comprises elevated source/drain material for a transistor of the line. Subsequently, conductivity-modifying impurity is provided into the elevated source/drain material. In another embodiment, a common step is utilized to provide conductivity enhancing impurity into both elevated source/drain material and material of the gate line. In another embodiment, the undoped semiconductive layer is first patterned and etched to provide elevated source/drain regions prior to provision of the conductivity-modifying impurity.
    Type: Grant
    Filed: December 1, 1998
    Date of Patent: April 3, 2001
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, Lyle Jones
  • Patent number: 6165827
    Abstract: The invention includes a method for forming graded junction regions comprising: a) providing a semiconductor material wafer; b) providing a transistor gate over the semiconductor material wafer, the transistor gate having opposing lateral sidewalls; c) providing sidewall spacers adjacent the sidewalls of the transistor gate, the sidewall spacers having a lateral thickness; d) decreasing the lateral thickness of the sidewall spacers; and e) after decreasing the lateral thickness of the sidewall spacers, implanting a conductivity-enhancing dopant into the semiconductor material to form graded junction regions operatively adjacent the transistor gate.
    Type: Grant
    Filed: October 6, 1998
    Date of Patent: December 26, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, David J. Keller
  • Patent number: 6159813
    Abstract: A process for grading the junctions of a lightly doped drain (LDD) N-channel MOSFET by performing a low dosage phosphorous implant after low and high dosage arsenic implants have been performed during the creation of the N- LDD regions and N+ source and drain electrodes. The phosphorous implant is driven to diffuse across both the electrode/LDD junctions and the LDD/channel junctions.
    Type: Grant
    Filed: March 17, 1997
    Date of Patent: December 12, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, Charles Dennison
  • Patent number: 6150204
    Abstract: In one aspect of the invention, a semiconductor processing method includes: a) providing a semiconductor substrate; b) defining a first conductivity type region and a second conductivity type region of the semiconductor substrate; c) providing a first transistor gate over the first type region which defines a first source area and a first drain area operatively adjacent thereto; d) providing a second transistor gate over the second type region which defines a second source area and a second drain area operatively adjacent thereto; and e) blanket implanting a conductivity enhancing dopant of the second conductivity type through the first source and drain areas of the first conductivity region and the second source and drain areas of the second conductivity region to provide second conductivity type regular LDD implant regions within the substrate operatively adjacent the first transistor gate and to provide second conductivity type halo implant regions within the substrate operatively adjacent the second trans
    Type: Grant
    Filed: November 16, 1998
    Date of Patent: November 21, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, Kirk Prall
  • Patent number: 6136637
    Abstract: A method for forming CMOS DRAM circuitry is disclosed and which includes forming a substrate comprising an array NMOS region, a peripheral NMOS region, and a peripheral PMOS region; forming a pair of insulated and spaced gate lines in the array NMOS region; forming at least one electrically conductive plug in the array NMOS region and which spans between the pair of gate lines; forming a barrier layer over the pair of gate lines in the array NMOS region, the peripheral NMOS and the peripheral PMOS region; and patterning and etching in the peripheral PMOS region to form peripheral PMOS region gate lines including removing a portion of the barrier layer in the PMOS peripheral region and leaving barrier layer material in the NMOS region masking over the electrically conductive plug
    Type: Grant
    Filed: July 28, 1998
    Date of Patent: October 24, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, David J. Keller, Tyler A. Lowrey
  • Patent number: 6130137
    Abstract: A method of forming a resistor from semiconductive material includes, a) providing a substrate; b) providing a layer of semiconductive material over the substrate; c) providing a pair of openings into the semiconductive material layer; d) plugging the pair of openings with an electrically conductive material to define a pair of electrically conductive pillars within the semiconductive material, the pair of pillars having semiconductive material extending therebetween to provide a resistor construction; and e) providing a conductive node to each of the electrically conductive pillars.
    Type: Grant
    Filed: October 13, 1998
    Date of Patent: October 10, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Kirk Prall, Pierre C. Fazan, Aftab Ahmad, Howard E. Rhodes, Werner Juengling, Pai-Hung Pan, Tyler Lowrey
  • Patent number: 6107145
    Abstract: A method for forming a field effect transistor on a substrate includes providing a wordline on the substrate; providing composite masking spacers laterally outward relative to the wordline, the composite masking spacers comprising at least two different materials; removing at least one of the materials of the composite masking spacers to effectively expose the substrate area adjacent to the wordline for conductivity enhancing doping; and subjecting the effectively exposed substrate to conductivity enhancing doping to form source/drain regions.
    Type: Grant
    Filed: May 15, 1998
    Date of Patent: August 22, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Charles H. Dennison, Aftab Ahmad
  • Patent number: 6090685
    Abstract: A semiconductor structure pad oxide layer is enlarged by local oxidation of silicon to form a field oxide. An etchback causes the thinnest portions of the field oxide to recede such that a portion of the semiconductor substrate is exposed. An etch through the exposed portion of the semiconductor substrate forms a microtrench between the field oxide and the nitride layer with a lateral dimension that is less than that currently achievable by conventional photolithography. The microtrench is then filled by oxide or nitride growth or by deposition of a dielectric material. In another embodiment, formation of the microtrench is carried out as set forth above, but the nitride layer is removed immediately following trench formation. Alternatively, the pad oxide layer is stripped and a new oxide layer is regrown that substantially covers all exposed surfaces of active areas of the semiconductor substrate.
    Type: Grant
    Filed: August 22, 1997
    Date of Patent: July 18, 2000
    Assignee: Micron Technology Inc.
    Inventors: Fernando Gonzales, Mike Violette, Nanseng Jeng, Aftab Ahmad, Klaus Schuegraf
  • Patent number: 6046472
    Abstract: A process for grading the junctions of a lightly doped drain (LDD) N-channel MOSFET by performing a low dosage phosphorous implant after low and high dosage arsenic implants have been performed during the creation of the N- LDD regions and N+ source and drain electrodes. The phosphorous implant is driven to diffuse across both the electrode/LDD junctions and the LDD/channel junctions.
    Type: Grant
    Filed: October 14, 1997
    Date of Patent: April 4, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, Charles Dennison
  • Patent number: 6037639
    Abstract: A process is provided for forming an isolating nitride film to isolate gate polysilicon of a gate structure. Specifically, the process comprises providing a channel region defined by a source and drain region of a semiconductor substrate having a gate structure comprising an isolating oxide layer positioned on the channel region and the polysilicon layer positioned on the oxide layer. More specifically, the process comprises the steps of forming the nitrogen implanted regions over the semiconductor substrate by implanting nitrogen atoms into those regions and growing spacers from exposed portions of the polysilicon layer. During the spacer growth, the spacer grows vertically as well as laterally extending under the polysilicon edges. Diffusion of nitrogen atoms to the substrate surface forms silicon nitride under the gate edges, which minimizes current leakages into gate polysilicon.
    Type: Grant
    Filed: June 9, 1997
    Date of Patent: March 14, 2000
    Assignee: Micron Technology, Inc.
    Inventor: Aftab Ahmad
  • Patent number: 5946588
    Abstract: A process for making thin gate oxides comprising the layering of a semiconductor substrate with at least an oxide layer and a nitride layer. The layers are then patterned and etched, thereby exposing portions of the substrate. The substrate is then doped, thereby creating a channel stop region. The exposed portions of the substrate are oxidized, thereby creating a field oxide region. The oxide and nitride layers are removed, thereby exposing sites of active areas, and a gate oxide layer grown in an ozone-containing atmosphere.
    Type: Grant
    Filed: January 7, 1997
    Date of Patent: August 31, 1999
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, Randhir P. S. Thakur, J. Brett Rolfson, Brian Benard
  • Patent number: 5940712
    Abstract: A method of forming a resistor from semiconductive material includes, a) providing a substrate; b) providing a layer of semiconductive material over the substrate; c) providing a pair of openings into the semiconductive material layer; d) plugging the pair of openings with an electrically conductive material to define a pair of electrically conductive pillars within the semiconductive material, the pair of pillars having semiconductive material extending therebetween to provide a resistor construction; and e) providing a conductive node to each of the electrically conductive pillars.
    Type: Grant
    Filed: September 22, 1997
    Date of Patent: August 17, 1999
    Assignee: Micron Technology, Inc.
    Inventors: Kirk Prall, Pierre C. Fazan, Aftab Ahmad, Howard E. Rhodes, Werner Juengling, Pai-Hung Pan, Tyler Lowrey
  • Patent number: 5939761
    Abstract: A method for forming a field effect transistor on a substrate includes providing a wordline on the substrate; providing composite masking spacers laterally outward relative to the wordline, the composite masking spacers comprising at least two different materials; removing at least one of the materials of the composite masking spacers to effectively expose the substrate area adjacent to the wordline for conductivity enhancing doping; and subjecting the effectively exposed substrate to conductivity enhancing doping to form source/drain regions.
    Type: Grant
    Filed: September 15, 1997
    Date of Patent: August 17, 1999
    Assignee: Micron Technology, Inc.
    Inventors: Charles H. Dennison, Aftab Ahmad
  • Patent number: 5923977
    Abstract: A method for forming CMOS DRAM circuitry is disclosed and which includes forming a substrate comprising an array NMOS region, a peripheral NMOS region, and a peripheral PMOS region; forming a pair of insulated and spaced gate lines in the array NMOS region; forming at least one electrically conductive plug in the array NMOS region and which spans between the pair of gate lines; forming a barrier layer over the pair of gate lines in the array NMOS region, the peripheral NMOS and the peripheral PMOS region; and patterning and etching in the peripheral PMOS region to form peripheral PMOS region gate lines including removing a portion of the barrier layer in the PMOS peripheral region and leaving barrier layer material in the NMOS region masking over the electrically conductive plug.
    Type: Grant
    Filed: November 14, 1997
    Date of Patent: July 13, 1999
    Assignee: Micron Technology, Inc.
    Inventors: Aftab Ahmad, David J. Keller, Tyler A. Lowrey
  • Patent number: 5923078
    Abstract: A method of forming a resistor from semiconductive material includes, a) providing a substrate; b) providing a layer of semiconductive material over the substrate; c) providing a pair of openings into the semiconductive material layer; d) plugging the pair of openings with an electrically conductive material to define a pair of electrically conductive pillars within the semiconductive material, the pair of pillars having semiconductive material extending therebetween to provide a resistor construction; and e) providing a conductive node to each of the electrically conductive pillars.
    Type: Grant
    Filed: May 15, 1998
    Date of Patent: July 13, 1999
    Assignee: Micron Technology, Inc.
    Inventors: Kirk Prall, Pierre C. Fazan, Aftab Ahmad, Howard E. Rhodes, Werner Juengling, Pai-Hung Pan, Tyler Lowrey