Patents by Inventor Amitava Chatterjee

Amitava Chatterjee 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: 20020086489
    Abstract: Silicide formation on the surface of the emitter in a vertical BJT is blocked by adding polysilicon lines with nitride sidewalls. The poly and nitride prevent silicide formation where they are deposited, decreasing the ratio of silicided area to total area and increasing emitter efficiency.
    Type: Application
    Filed: November 8, 2001
    Publication date: July 4, 2002
    Inventor: Amitava Chatterjee
  • Patent number: 6413824
    Abstract: High performance digital transistors (140) and analog transistors (144) are formed at the same time. The digital transistors (140) include pocket regions (134) for optimum performance. These pocket regions (134) are partially or completely suppressed from at least the drain side of the analog transistors (144) to provide a flat channel doping profile on the drain side. The flat channel doping profile provides high early voltage and higher gain. The suppression is accomplished by using the HVLDD implants for the analog transistors (144).
    Type: Grant
    Filed: June 8, 2000
    Date of Patent: July 2, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Amitava Chatterjee, Alec J. Morton, Mark S. Rodder, Taylor R. Efland, Chin-Yu Tsai, James R. Hellums
  • Publication number: 20020083399
    Abstract: A method (40) of designing a circuit comprising a plurality of transistors (10, 46T, 60T). Each transistor of the plurality of transistors comprises an active region, a gate (G1, G2), a first source/drain (S/D1, S/D3) in the active region, a second source/drain in the active region, and at least one contact in each of the first source/drain and the second source/drain. The method comprises various steps. The method specifies a first set of distances for each transistor in a first set (10) of transistors in the plurality of transistors, wherein the first set of distances comprises a gate length (Lg), a gate width (Wg), and a distance representative of one or both of a first contact-to-edge distance (CTE1) and a first contact-to-gate distance (CTG1).
    Type: Application
    Filed: October 25, 2001
    Publication date: June 27, 2002
    Inventors: Amitava Chatterjee, Sreedhar Natarajan
  • 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
  • Patent number: 6352900
    Abstract: A method for controlled oxide growth on transistor gates. A first film (40) is formed on a semiconductor substrate (10). The film is implanted with a first species and patterned to form a transistor gate (45) . The transistor gate (45) and the semiconductor substrate (10) is implanted with a second species and the transistor gate (45) oxidized to produce an oxide film (80) on the side surface of the transistor gate (45).
    Type: Grant
    Filed: July 18, 2000
    Date of Patent: March 5, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Manoj Mehrotra, Jerry Che-Jen Hu, Amitava Chatterjee, Mark S. Rodder
  • Publication number: 20010046760
    Abstract: A method of fabricating an improved gate structure that may be used in a transistor. A primary insulation layer (22) may be formed adjacent a substrate (12). A disposable gate (24) may be formed adjacent the primary insulation layer (22). An isolation dielectric layer (26) may be formed adjacent the primary insulation layer (22). The disposable gate (24) may be removed to expose a portion of the primary insulation layer (22). The exposed portion of the primary insulation layer (22) may be removed to expose a portion of the substrate (12). The primary insulation layer (22) may be selectively removable relative to the isolation dielectric layer (26). A gate insulator (30) may be formed on the exposed portion of the substrate (12). A gate (32) may be formed adjacent the gate insulator (30).
    Type: Application
    Filed: July 6, 2001
    Publication date: November 29, 2001
    Inventors: Amitava Chatterjee, Wei William Lee, Greg A. Hames, Qizhi He, Maureen Hanratty, Iqbal Ali
  • Patent number: 6313010
    Abstract: A trench isolation structure including high density plasma enchanced silicon dioxide trench filling (122) with chemical mechanical polishing removal of non-trench oxide.
    Type: Grant
    Filed: June 9, 1997
    Date of Patent: November 6, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Somnath S. Nag, Amitava Chatterjee, Ih-Chin Chen
  • Patent number: 6306725
    Abstract: An isolation trench (60) comprising a trench (20) formed in a semiconductor layer (12). A barrier layer (22) may be formed along the trench (20). A layer (50) of an insulation material may be formed over the barrier layer (22). A high density layer (55) of the insulation material may be formed in the trench (20) over the layer (50).
    Type: Grant
    Filed: May 11, 2000
    Date of Patent: October 23, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Somnath S. Nag, Amitava Chatterjee
  • Patent number: 6307230
    Abstract: A transistor having an improved sidewall gate structure and method of construction is provided. The improved sidewall gate structure may include a semiconductor substrate (12) having a channel region (20). A gate insulation (36) may be adjacent the channel region (20) of the semiconductor substrate (12). A gate (38) may be formed adjacent the gate insulation (36). A sidewall insulation body (28) may be formed adjacent a portion of the gate (38). The sidewall insulation body (28) is comprised of a silicon oxynitride material. An epitaxial layer (30) may be formed adjacent a portion of the sidewall insulation body (28) and adjacent the semiconductor substrate (12) substantially outward of the channel region (20). A buffer layer (32) may be formed adjacent a portion of the sidewall insulation body (28) and adjacent the epitaxial layer (30).
    Type: Grant
    Filed: October 12, 1999
    Date of Patent: October 23, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Amitava Chatterjee, Wei William Lee, Greg A. Hames, Quzhi He, Iqbal Ali, Maureen A. Hanratty
  • Patent number: 6303420
    Abstract: A method for forming integrated circuit bipolar junction transistors for mixed signal circuits. The implants used to form the well regions of the CMOS circuits 20, 40 form the collector regions of bipolar junction transistors. The CMOS transistor pocket implants form the base region of the bipolar junction transistor, and the CMOS drain extension implants form the emitter region of the bipolar junction transistor.
    Type: Grant
    Filed: July 18, 2000
    Date of Patent: October 16, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Seetharaman Sridhar, Amitava Chatterjee, Hisashi Shichijo, Alec J. Morton
  • Patent number: 6297125
    Abstract: Air-bridges are formed at controlled lateral separations using the extremely high HF etch rate of a gap-fill spin-on-glass such as uncured hydrogen silsequioxane (HSQ) in combination with other dielectrics having a much slower etch rate in HF. The advantages of an air-bridge system with controlled lateral separations include providing an interconnect isolation dielectric which meets all requirements for sub-0.5 micron technologies and providing a device with reduced reliability problems.
    Type: Grant
    Filed: January 19, 1999
    Date of Patent: October 2, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Somnath S. Nag, Amitava Chatterjee, Girish A. Dixit
  • 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: 6232188
    Abstract: A method for forming a MOSFET transistor using a disposable gate process which has no need for a chemical mechanical polishing step to expose the disposable gate after deposition of the field dielectric. The field dielectric is deposited non-conformally by HDP-CVD over a disposable gate structure so that the disposable gate remains partially exposed. After deposition, the partially exposed disposable gate may then be removed by selective isotropic etch. In the space left by the removal of the disposable gate, the gate dielectric may be formed and the gate electrode may be deposited. Eliminating the need for exposure of the disposable gate by CMP eliminates the problem of polish rate dependence on gate pattern density.
    Type: Grant
    Filed: July 29, 1998
    Date of Patent: May 15, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Suhail Murtaza, Amitava Chatterjee
  • 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: 6180978
    Abstract: A counter-doped epitaxial silicon (doped opposite to the substrate type) is used to form the buried layer in a CMOS transistor, while maintaining an abrupt channel profile. Shallow source/drain junctions with abrupt source/drain profiles may be formed using raised (or elevated) source/drain design. The invention encompasses a transistor structure including a doped silicon substrate, and an oppositely-doped epitaxial silicon layer formed on the substrate. A gate is formed on the epitaxial layer, the gate defining a channel region in the epitaxial layer underneath the gate. A layer is formed on the epitaxial silicon layer on opposing sides of, and is electrically isolated from, the gate.
    Type: Grant
    Filed: December 18, 1998
    Date of Patent: January 30, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: Amitava Chatterjee, Richard A. Chapman, Syed Suhail Murtaza
  • Patent number: 6143625
    Abstract: An isolation trench (60) may comprise a trench (20) formed in a semiconductor layer (12). A barrier layer (22) may be formed along the trench (20). A protective liner (50) may be formed over the barrier layer (22). The protective liner (50) may comprise a chemically deposited oxide. A high density layer of insulation material (55) may be formed in the trench (20) over the protective liner (50).
    Type: Grant
    Filed: September 10, 1998
    Date of Patent: November 7, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Ih-Chin Chen, Amitava Chatterjee, Somnath S. Nag
  • Patent number: 6127232
    Abstract: A counter-doped epitaxial silicon (doped opposite to the substrate type) is used to form the buried layer in a CMOS transistor, while maintaining an abrupt channel profile. Shallow source/drain junctions with abrupt source/drain profiles may be formed using raised (or elevated) source/drain design. The invention encompasses a transistor structure including a doped silicon substrate, and an oppositely-doped epitaxial silicon layer formed on the substrate. A gate is formed on the epitaxial layer, the gate defining a channel region in the epitaxial layer underneath the gate. A layer is formed on the epitaxial silicon layer on opposing sides of, and is electrically isolated from, the gate.
    Type: Grant
    Filed: June 24, 1999
    Date of Patent: October 3, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Amitava Chatterjee, Richard A. Chapman, Syed Suhail Murtaza
  • Patent number: 6125021
    Abstract: An integrated circuit (10) with ESD protection is provided. The integrated circuit (10) includes a clamping device (28) connected to an input pad (12) of the integrated circuit and to ground (22). The clamping device (28) limits the peak voltage of an ESD pulse applied to the input pad (12) by conducting it to ground (22). A protection device (16) is connected to an input pad (12) of the integrated circuit (10) and to ground. The protection device (16) discharges the energy of the ESD pulse to ground. The protection device (16) is coordinated with the clamping device (28) such that the clamping device (28) turns on before the protection device (16).
    Type: Grant
    Filed: April 30, 1997
    Date of Patent: September 26, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Charvaka Duvvury, Steven E. Marum, Amitava Chatterjee
  • Patent number: 6117741
    Abstract: A transistor having an improved sidewall gate structure and method of construction is provided. The improved sidewall gate structure may include a semiconductor substrate (12) having a channel region (20). A gate insulation (36) may be adjacent the channel region (20) of the semiconductor substrate (12). A gate (38) may be formed adjacent the gate insulation (36). A sidewall insulation body (28) may be formed adjacent a portion of the gate (38). The sidewall insulation body (28) is comprised of a silicon oxynitride material. An epitaxial layer (30) may be formed adjacent a portion of the sidewall insulation body (28) and adjacent the semiconductor substrate (12) substantially outward of the channel region (20). A buffer layer (32) may be formed adjacent a portion of the sidewall insulation body (28) and adjacent the epitaxial layer (30).
    Type: Grant
    Filed: January 5, 1999
    Date of Patent: September 12, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Amitava Chatterjee, Wei William Lee, Greg A. Hames, Quzhi He, Iqbal Ali, Maureen A. Hanratty
  • Patent number: 6114186
    Abstract: An improved method is provided for integrating HSQ into integrated circuit structures and processes, especially those requiring multiple levels of interconnect lines. In a preferred embodiment, interconnect lines 14 are first patterned and etched on a substrate 10. A low-k material such as hydrogen silsesquioxane (HSQ) 18 is spun across the surface of the wafer to fill areas between interconnect lines. A capping layer such as SiO.sub.2 20 is applied to on top of the low-k material. The HSQ is then heated to cure. A thick SiO.sub.2 planarization layer 22 may then be applied and planarized. In other embodiments, the HSQ and SiO.sub.2 process steps can be repeated for multiple layers of HSQ.
    Type: Grant
    Filed: July 11, 1997
    Date of Patent: September 5, 2000
    Assignee: Texas Instruments Incorporated
    Inventors: Shin-Puu Jeng, Kelly J. Taylor, Amitava Chatterjee