Patents by Inventor Mahalingam Nandakumar

Mahalingam Nandakumar 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: 6617217
    Abstract: Retrograde wells are formed by implanting through nitride films (40). Nitride films (40) are formed after STI (20) formation. By selectively masking a portion of the wafer with photoresist (47) after portions of a retrograde well are formed (45, 50, 55, and 60) the channeling of the subsequent zero degree implants is reduced.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: September 9, 2003
    Assignee: Texas Instruments Incorpated
    Inventors: Mahalingam Nandakumar, Dixit Kapila, Seetharaman Sridhar
  • Publication number: 20030141550
    Abstract: A method of fabricating a transistor (10) comprises forming source and drain regions (46) and (47) using a first sidewall (42) and (43) as a mask and forming a deep blanket source and drain regions (54) and (56) using a second sidewall (50) and (51) as a mask, the second sidewall (50) and (51) comprising at least part of the first sidewall (42) and (43).
    Type: Application
    Filed: January 30, 2003
    Publication date: July 31, 2003
    Inventor: Mahalingam Nandakumar
  • Patent number: 6579770
    Abstract: A transistor (30) and method for forming a transistor using an edge blocking material (24) is disclosed herein. The edge blocking material (24) may be located adjacent a gate (22) or disposable gate or may be part of a disposable gate. During an angled pocket implant, the edge blocking material (24) blocks some dopant from entering the semiconductor body (10) and the dopant (18) placed under the edge blocking material is located at a given distance below the surface of the semiconductor body (10).
    Type: Grant
    Filed: July 5, 2001
    Date of Patent: June 17, 2003
    Assignee: Texas Instruments Incorporated
    Inventors: Mark S. Rodder, Mahalingam Nandakumar
  • Publication number: 20030040148
    Abstract: An implant at HVGX pattern (step 102c) is provided to allow selective transistor threshold voltage Vth adjustment on the core transistors without affecting the I/O transistor threshold voltage Vt. The implant provides independently tuned either NMOS core transistors and I/O transistor Vth or PMOS core transistors and I/O transistor Vth.
    Type: Application
    Filed: August 9, 2002
    Publication date: February 27, 2003
    Inventors: Mahalingam Nandakumar, Youngmin Kim, Amitava Chatterjee
  • Publication number: 20020185682
    Abstract: A short-channel NMOS transistor in a p-well, bordered laterally on each side by an isolation region and vertically by a channel stop region, has a n-source and a n-drain, each comprising a shallow region extending to the transistor gate and a deeper region recessed from the gate, and both having a depletion region when reverse biased. The shallow regions are surrounded in part by an enhanced p-doping implant pocket. The transistor further has in these regions of enhanced p-doping another region of a presistivity higher than the remainder of the semiconductor. These regions extend laterally approximately from the inner border of the respective shallow region to the inner border of the respective recessed region, and vertically from a depth just below the depletion regions of source and drain to approximately the top of the channel stop regions.
    Type: Application
    Filed: June 7, 2001
    Publication date: December 12, 2002
    Inventors: Mahalingam Nandakumar, Song Zhao, Youngmin Kim
  • Patent number: 6479339
    Abstract: A mixed voltage CMOS process for high reliability and high performance core transistors and input-output and analog transistors with reduced mask steps. A patterned silicon nitride film 160 is used to selectively mask various implant species during the formation of the LDD regions 180, 220, and the pocket regions 190, 230 of the core transistors 152, 154. The LDD regions 240, 200 of the I/O or analog transistors 156, 158 are simultaneously formed during the process.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: November 12, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Mahalingam Nandakumar, Amitava Chatterjee
  • Publication number: 20020042166
    Abstract: A mixed voltage CMOS process for high reliability and high performance core transistors and input-output and analog transistors with reduced mask steps. A patterned silicon nitride film 160 is used to selectively mask various implant species during the formation of the LDD regions 180, 220, and the pocket regions 190, 230 of the core transistors 152, 154. The LDD regions 240, 200 of the I/O or analog transistors 156, 158 are simultaneously formed during the process.
    Type: Application
    Filed: September 28, 2001
    Publication date: April 11, 2002
    Inventors: Mahalingam Nandakumar, Amitava Chatterjee
  • Publication number: 20020042184
    Abstract: Retrograde wells are formed by implanting through nitride films (40). Nitride films (40) are formed after STI (20) formation. By selectively masking a portion of the wafer with photoresist (47) after portions of a retrograde well are formed (45, 50, 55, and 60) the channeling of the subsequent zero degree implants is reduced.
    Type: Application
    Filed: September 28, 2001
    Publication date: April 11, 2002
    Inventors: Mahalingam Nandakumar, Dixit Kapila, Seetharaman Sridhar
  • Patent number: 6362062
    Abstract: A method for forming a MOS transistor using a disposable sidewall spacer process. A gate dielectric (20) and a gate structure (25) is formed on a semiconductor substrate (10). Insulator films (30) and (35) and formed and a LOCOS type film (80) is formed on the substrate (10). A spacer structure (86) is formed on the gate structure (25) and implants are performed to form the source drain (50), drain extension (110), and pocket regions (120).
    Type: Grant
    Filed: September 6, 2000
    Date of Patent: March 26, 2002
    Assignee: Texas Instruments Incorporated
    Inventor: Mahalingam Nandakumar
  • Patent number: 6326281
    Abstract: Silicon substrate isolation by epitaxial growth of silicon through windows in a mask made of silicon nitride (202) on silicon oxide (201) with the silicon oxide etched to undercut the silicon nitride; the mask is on a silicon substrate.
    Type: Grant
    Filed: September 23, 1999
    Date of Patent: December 4, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Katherine E. Violette, Rick L. Wise, Stanton P. Ashburn, Mahalingam Nandakumar, Douglas T. Grider
  • Publication number: 20010036713
    Abstract: A transistor (30) and method for forming a transistor using an edge blocking material (24) is disclosed herein. The edge blocking material (24) may be located adjacent a gate (22) or disposable gate or may be part of a disposable gate. During an angled pocket implant, the edge blocking material (24) blocks some dopant from entering the semiconductor body (10) and the dopant (18) placed under the edge blocking material is located at a given distance below the surface of the semiconductor body (10).
    Type: Application
    Filed: July 5, 2001
    Publication date: November 1, 2001
    Inventors: Mark S. Rodder, Mahalingam Nandakumar
  • Patent number: 6306712
    Abstract: A transistor (30) and method for forming a transistor using an edge blocking material (24) is disclosed herein. The edge blocking material (24) may be located adjacent a gate (22) or disposable gate or may be part of a disposable gate. During an angled pocket implant, the edge blocking material (24) blocks some dopant from entering the semiconductor body (10) and the dopant (18) placed under the edge blocking material is located at a given distance below the surface of the semiconductor body (10).
    Type: Grant
    Filed: December 3, 1998
    Date of Patent: October 23, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Mark S. Rodder, Mahalingam Nandakumar
  • Patent number: 6287920
    Abstract: A method for forming multiple threshold voltage integrated circuit transistors. Angled pocket type implants (80) are performed to form asymmetric regions (90) and (95). The source and drain regions (120, 121, 122, and 123) are connected such that multiple threshold voltage transistors are formed.
    Type: Grant
    Filed: August 16, 2000
    Date of Patent: September 11, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Amitava Chatterjee, Mahalingam Nandakumar
  • Patent number: 6274449
    Abstract: The invention comprises a method of determining the thermal straggle of microelectronic devices having a pocket dopant implant that is formed under substantially the same doping conditions. The method comprises measuring the operating characteristics of each device (32) and obtaining a one-dimensional doping profile of dopant ions in the devices (30). A total lateral straggle of the dopant ions in the devices is determined in response to the operating characteristics and the one-dimensional doping profile of the dopant ions (34). An as-implanted straggle of the dopant ions in the devices is determined in response to the doping conditions (36). A thermal straggle of the dopant ions is calculated utilizing the as-implanted straggle and the total lateral straggle (38).
    Type: Grant
    Filed: December 18, 1998
    Date of Patent: August 14, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Karthik Vasanth, Mahalingam Nandakumar
  • Patent number: 6258644
    Abstract: A mixed voltage CMOS process for high reliability and high performance core transistors and input-output transistors with reduced mask steps. A gate stack (30) is formed over the silicon substrate (10). Ion implantation is performed of a first species and a second species to produce the doping profiles (70, 80, 90, 100) in the input-output transistors.
    Type: Grant
    Filed: February 8, 2000
    Date of Patent: July 10, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Mark S. Rodder, Manoj Mehrotra, Mahalingam Nandakumar
  • Patent number: 6228725
    Abstract: A low power transistor (70, 70′) formed in a face of a semiconductor layer (86) of a first conductivity type. The transistor includes a source and drain regions (76, 78) of a second conductivity type formed in the face of the semiconductor layer, and a gate (72) insulatively disposed adjacent the face of the semiconductor layer and between the source and drain regions. A layer of counter doping (80, 80′) of the second conductivity type is formed adjacent to the face of the semiconductor layer generally between the source and drain regions. A first and second pockets (82, 84, 82′, 84′) of the first conductivity type may also be formed generally adjacent to the source and drain regions and the counter doped layer (80, 80′).
    Type: Grant
    Filed: March 30, 1999
    Date of Patent: May 8, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Mahalingam Nandakumar, Amitava Chatterjee, Mark S. Rodder, Ih-Chin Chen
  • Patent number: 6204073
    Abstract: A method for forming STI that allows for in-situ moat/trench width electrical measurement is disclosed herein. A conductive layer (18) is used in the hard mask (20) for trench etch. After the hard mask (20) is formed and the trench (12) is etched, the resistance of the conductive layer (18) is measured over a predefined length. Since the length is known, the average width of the hard mask (20)/moat (11) can be determined. Once the width of the moat (11) is known, the width of the trench (12) can easily be determined by subtracting the width of the moat (12) from the pitch, which is a known factor.
    Type: Grant
    Filed: December 2, 1999
    Date of Patent: March 20, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Mahalingam Nandakumar, Seetharaman Sridhar
  • Patent number: 6150669
    Abstract: A first test structure (40) is used to measure both the gate resistance/linewidth and transistor performance. A gate line (42) crosses a moat region (44) with source (48) and drain (50) regions formed on either side of the gate line (42). The gate line (42) is connected to four probe pads (52) in an H configuration for accurate linewidth measurements. A second test structure (70) may be used alone or in conjunction with the first test structure. A single gate line (72) crosses a moat region (74) several times. This allows both capacitance and gate gate-resistance measurements with the same test structure and for more accurate TLD measurement.
    Type: Grant
    Filed: December 9, 1999
    Date of Patent: November 21, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Mahalingam Nandakumar, Greg C. Baldwin, Andrew T. Appel
  • Patent number: 5976937
    Abstract: Method of making transistors having ultrashallow source and drain junction with reduced gate overlap may comprise forming a first gate electrode (124) separated from a first active area (126) of a semiconductor layer (112) by a first gate insulator (130). A second gate electrode (140) may be formed substantially perpendicular to the first gate electrode (124) and separated from a second active area (142) of the semiconductor layer by a second gate insulator (146). A masking layer (160) may be formed over the semiconductor layer (112) and expose a source and a drain section (162 and 164) of the first active area (126) and a source and a drain section (166 and 168) of the second active area (142). Dopants may be implanted from a first direction substantially parallel to the first gate electrode (124) into the source and drain sections (166 and 168) of the first active area (126).
    Type: Grant
    Filed: August 19, 1998
    Date of Patent: November 2, 1999
    Assignee: Texas Instruments Incorporated
    Inventors: Mark S. Rodder, Mahalingam Nandakumar
  • Patent number: 5917219
    Abstract: A low power transistor (70, 70') formed in a face of a semiconductor layer (86) of a first conductivity type. The transistor includes a source and drain regions (76, 78) of a second conductivity type formed in the face of the semiconductor layer, and a gate (72) insulatively disposed adjacent the face of the semiconductor layer and between the source and drain regions. A layer of counter doping (80, 80') of the second conductivity type is formed adjacent to the face of the semiconductor layer generally between the source and drain regions. A first and second pockets (82, 84, 82', 84') of the first conductivity type may also be formed generally adjacent to the source and drain regions and the counter doped layer (80, 80').
    Type: Grant
    Filed: October 3, 1996
    Date of Patent: June 29, 1999
    Assignee: Texas Instruments Incorporated
    Inventors: Mahalingam Nandakumar, Amitava Chatterjee, Mark S. Rodder, Ih-Chin Chen