Patents by Inventor Seetharaman Sridhar

Seetharaman Sridhar 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: 20180097517
    Abstract: An integrated circuit chip includes a bimodal power N-P-Laterally Diffused Metal Oxide Semiconductor (LDMOS) device having an N-gate coupled to receive an input signal and a level shifter coupled to receive the input signal and to provide a control signal to a P-gate driver of the N-P-LDMOS device. A method of operating an N-P-LDMOS power device is also disclosed.
    Type: Application
    Filed: November 10, 2017
    Publication date: April 5, 2018
    Inventors: Yongxi Zhang, Sameer P. Pendharkar, Philip L. Hower, Salvatore Giombanco, Filippo Marino, Seetharaman Sridhar
  • Patent number: 9905638
    Abstract: A method of forming a semiconductor device includes etching a high aspect ratio, substantially perpendicular trench in a semiconductor region doped with a first dopant having first conductivity type and performing a first cycle for depositing silicon doped with a second dopant on an inner surface of the high aspect ratio, substantially perpendicular trench, the first cycle comprising alternately depositing silicon at a first constant pressure and etching the deposited silicon at an etching pressure that ramps up from a first value to a second value, the second dopant having a second conductivity type that is opposite from the first conductivity type.
    Type: Grant
    Filed: September 30, 2016
    Date of Patent: February 27, 2018
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Tatsuya Tominari, Satoshi Suzuki, Seetharaman Sridhar, Christopher Boguslaw Kocon, Simon John Molloy, Hideaki Kawahara
  • Patent number: 9843322
    Abstract: An integrated circuit chip includes a bimodal power N-P-Laterally Diffused Metal Oxide Semiconductor (LDMOS) device having an N-gate coupled to receive an input signal and a level shifter coupled to receive the input signal and to provide a control signal to a P-gate driver of the N-P-LDMOS device. A method of operating an N-P-LDMOS power device is also disclosed.
    Type: Grant
    Filed: March 11, 2016
    Date of Patent: December 12, 2017
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Yongxi Zhang, Sameer P. Pendharkar, Philip L. Hower, Salvatore Giombanco, Filippo Marino, Seetharaman Sridhar
  • Publication number: 20170301673
    Abstract: An integrated circuit containing a first plurality of MOS transistors operating in a low voltage range, and a second plurality of MOS transistors operating in a mid voltage range, may also include a high-voltage MOS transistor which operates in a third voltage range significantly higher than the low and mid voltage ranges, for example 20 to 30 volts. The high-voltage MOS transistor has a closed loop configuration, in which a drain region is surrounded by a gate, which is in turn surrounded by a source region, so that the gate does not overlap field oxide. The integrated circuit may include an n-channel version of the high-voltage MOS transistor and/or a p-channel version of the high-voltage MOS transistor. Implanted regions of the n-channel version and the p-channel version are formed concurrently with implanted regions in the first and second pluralities of MOS transistors.
    Type: Application
    Filed: June 28, 2017
    Publication date: October 19, 2017
    Inventors: Binghua Hu, Pinghai Hao, Sameer Pendharkar, Seetharaman Sridhar, Jarvis Jacobs
  • Publication number: 20170288052
    Abstract: A semiconductor device contains a vertical MOS transistor having a trench gate in trenches extending through a vertical drift region to a drain region. The trenches have field plates under the gate; the field plates are adjacent to the drift region and have a plurality of segments. A dielectric liner in the trenches separating the field plates from the drift region has a thickness great than a gate dielectric layer between the gate and the body. The dielectric liner is thicker on a lower segment of the field plate, at a bottom of the trenches, than an upper segment, immediately under the gate. The trench gate may be electrically isolated from the field plates, or may be connected to the upper segment. The segments of the field plates may be electrically isolated from each other or may be connected to each other in the trenches.
    Type: Application
    Filed: June 14, 2017
    Publication date: October 5, 2017
    Inventors: Hideaki Kawahara, Seetharaman Sridhar, Christopher Boguslaw Kocon, Simon John Molloy, Hong Yang
  • Publication number: 20170264289
    Abstract: An integrated circuit chip includes a bimodal power N-P-Laterally Diffused Metal Oxide Semiconductor (LDMOS) device having an N-gate coupled to receive an input signal and a level shifter coupled to receive the input signal and to provide a control signal to a P-gate driver of the N-P-LDMOS device. A method of operating an N-P-LDMOS power device is also disclosed.
    Type: Application
    Filed: March 11, 2016
    Publication date: September 14, 2017
    Inventors: Yongxi Zhang, Sameer P. Pendharkar, Philip L. Hower, Salvatore Giombanco, Filippo Marino, Seetharaman Sridhar
  • Patent number: 9741718
    Abstract: An integrated circuit containing a first plurality of MOS transistors operating in a low voltage range, and a second plurality of MOS transistors operating in a mid voltage range, may also include a high-voltage MOS transistor which operates in a third voltage range significantly higher than the low and mid voltage ranges, for example 20 to 30 volts. The high-voltage MOS transistor has a closed loop configuration, in which a drain region is surrounded by a gate, which is in turn surrounded by a source region, so that the gate does not overlap field oxide. The integrated circuit may include an n-channel version of the high-voltage MOS transistor and/or a p-channel version of the high-voltage MOS transistor. Implanted regions of the n-channel version and the p-channel version are formed concurrently with implanted regions in the first and second pluralities of MOS transistors.
    Type: Grant
    Filed: July 20, 2015
    Date of Patent: August 22, 2017
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Binghua Hu, Pinghai Hao, Sameer Pendharkar, Seetharaman Sridhar, Jarvis Jacobs
  • Patent number: 9735265
    Abstract: An integrated circuit including an isolated device which is isolated with a lower buried layer combined with deep trench isolation. An upper buried layer, with the same conductivity type as the substrate, is disposed over the lower buried layer, so that electrical contact to the lower buried layer is made at a perimeter of the isolated device. The deep trench isolation laterally surrounds the isolated device. Electrical contact to the lower buried layer sufficient to maintain a desired bias to the lower buried layer is made along less than half of the perimeter of the isolated device, between the upper buried layer and the deep trench.
    Type: Grant
    Filed: November 10, 2016
    Date of Patent: August 15, 2017
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Yongxi Zhang, Sameer Pendharkar, Seetharaman Sridhar
  • Patent number: 9711639
    Abstract: A semiconductor device contains a vertical MOS transistor having a trench gate in trenches extending through a vertical drift region to a drain region. The trenches have field plates under the gate; the field plates are adjacent to the drift region and have a plurality of segments. A dielectric liner in the trenches separating the field plates from the drift region has a thickness great than a gate dielectric layer between the gate and the body. The dielectric liner is thicker on a lower segment of the field plate, at a bottom of the trenches, than an upper segment, immediately under the gate. The trench gate may be electrically isolated from the field plates, or may be connected to the upper segment. The segments of the field plates may be electrically isolated from each other or may be connected to each other in the trenches.
    Type: Grant
    Filed: February 22, 2016
    Date of Patent: July 18, 2017
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Hideaki Kawahara, Seetharaman Sridhar, Christopher Boguslaw Kocon, Simon John Molloy, Hong Yang
  • Publication number: 20170133261
    Abstract: An integrated circuit is formed on a substrate containing a semiconductor material having a first conductivity type. A deep well having a second, opposite, conductivity type is formed in the semiconductor material of the first conductivity type. A deep isolation trench is formed in the substrate through the deep well so as separate an unused portion of the deep well from a functional portion of the deep well. The functional portion of the deep well contains an active circuit element of the integrated circuit. The separated portion of the deep well does not contain an active circuit element. A contact region having the second conductivity type and a higher average doping density than the deep well is formed in the separated portion of the deep well. The contact region is connected to a voltage terminal of the integrated circuit.
    Type: Application
    Filed: January 23, 2017
    Publication date: May 11, 2017
    Inventors: Yongxi Zhang, Eugen Mindricelu, Sameer Pendharkar, Seetharaman Sridhar
  • Publication number: 20170062611
    Abstract: An integrated circuit including an isolated device which is isolated with a lower buried layer combined with deep trench isolation. An upper buried layer, with the same conductivity type as the substrate, is disposed over the lower buried layer, so that electrical contact to the lower buried layer is made at a perimeter of the isolated device. The deep trench isolation laterally surrounds the isolated device. Electrical contact to the lower buried layer sufficient to maintain a desired bias to the lower buried layer is made along less than half of the perimeter of the isolated device, between the upper buried layer and the deep trench.
    Type: Application
    Filed: November 10, 2016
    Publication date: March 2, 2017
    Inventors: Yongxi ZHANG, Sameer PENDHARKAR, Seetharaman SRIDHAR
  • Patent number: 9553011
    Abstract: An integrated circuit is formed on a substrate containing a semiconductor material having a first conductivity type. A deep well having a second, opposite, conductivity type is formed in the semiconductor material of the first conductivity type. A deep isolation trench is formed in the substrate through the deep well so as separate an unused portion of the deep well from a functional portion of the deep well. The functional portion of the deep well contains an active circuit element of the integrated circuit. The separated portion of the deep well does not contain an active circuit element. A contact region having the second conductivity type and a higher average doping density than the deep well is formed in the separated portion of the deep well. The contact region is connected to a voltage terminal of the integrated circuit.
    Type: Grant
    Filed: December 10, 2013
    Date of Patent: January 24, 2017
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Yongxi Zhang, Eugen Mindricelu, Sameer Pendharkar, Seetharaman Sridhar
  • Patent number: 9525060
    Abstract: An integrated circuit including an isolated device which is isolated with a lower buried layer combined with deep trench isolation. An upper buried layer, with the same conductivity type as the substrate, is disposed over the lower buried layer, so that electrical contact to the lower buried layer is made at a perimeter of the isolated device. The deep trench isolation laterally surrounds the isolated device. Electrical contact to the lower buried layer sufficient to maintain a desired bias to the lower buried layer is made along less than half of the perimeter of the isolated device, between the upper buried layer and the deep trench.
    Type: Grant
    Filed: December 8, 2014
    Date of Patent: December 20, 2016
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Yongxi Zhang, Sameer Pendharkar, Seetharaman Sridhar
  • Publication number: 20160329423
    Abstract: A semiconductor device contains a vertical MOS transistor having a trench gate in trenches extending through a vertical drift region to a drain region. The trenches have field plates under the gate; the field plates are adjacent to the drift region and have a plurality of segments. A dielectric liner in the trenches separating the field plates from the drift region has a thickness great than a gate dielectric layer between the gate and the body. The dielectric liner is thicker on a lower segment of the field plate, at a bottom of the trenches, than an upper segment, immediately under the gate. The trench gate may be electrically isolated from the field plates, or may be connected to the upper segment. The segments of the field plates may be electrically isolated from each other or may be connected to each other in the trenches.
    Type: Application
    Filed: February 22, 2016
    Publication date: November 10, 2016
    Inventors: Hideaki Kawahara, Seetharaman Sridhar, Christopher Boguslaw Kocon, Simon John Molloy, Hong Yang
  • Publication number: 20160315159
    Abstract: An semiconductor device with a low resistance sinker contact wherein the low resistance sinker contact is etched through a first doped layer and is etched into a second doped layer and wherein the first doped layer overlies the second doped layer and wherein the second doped layer is more heavily doped that the first doped layer and wherein the low resistance sinker contact is filled with a metallic material.
    Type: Application
    Filed: June 21, 2016
    Publication date: October 27, 2016
    Inventors: Hong YANG, Seetharaman SRIDHAR, Yufei XIONG, Yunlong LIU, Zachary K. LEE, Peng HU
  • Publication number: 20160225897
    Abstract: An integrated circuit and method having an extended drain MOS transistor, wherein a diffused drain is deeper under a field oxide element in the drain than in a drift region under the gate. A field oxide hard mask layer is etched to define a drain field oxide trench area. Drain dopants are implanted through the drain field oxide trench area and a thermal drain drive is performed. Subsequently, the drain field oxide element is formed.
    Type: Application
    Filed: April 7, 2016
    Publication date: August 4, 2016
    Inventor: Seetharaman SRIDHAR
  • Patent number: 9397180
    Abstract: An semiconductor device with a low resistance sinker contact wherein the low resistance sinker contact is etched through a first doped layer and is etched into a second doped layer and wherein the first doped layer overlies the second doped layer and wherein the second doped layer is more heavily doped that the first doped layer and wherein the low resistance sinker contact is filled with a metallic material. A method for forming a semiconductor device with a low resistance sinker contact wherein the low resistance sinker contact is etched through a first doped layer and is etched into a second doped layer and wherein the first doped layer overlies the second doped layer and wherein the second doped layer is more heavily doped that the first doped layer and wherein the low resistance sinker contact is filled with a metallic material.
    Type: Grant
    Filed: April 24, 2015
    Date of Patent: July 19, 2016
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Hong Yang, Seetharaman Sridhar, Yufei Xiong, Yunlong Liu, Zachary K. Lee, Peng Hu
  • Patent number: 9337330
    Abstract: An integrated circuit and method having an extended drain MOS transistor, wherein a diffused drain is deeper under a field oxide element in the drain than in a drift region under the gate. A field oxide hard mask layer is etched to define a drain field oxide trench area. Drain dopants are implanted through the drain field oxide trench area and a thermal drain drive is performed. Subsequently, the drain field oxide element is formed.
    Type: Grant
    Filed: December 17, 2014
    Date of Patent: May 10, 2016
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventor: Seetharaman Sridhar
  • Patent number: 9299830
    Abstract: A semiconductor device contains a vertical MOS transistor having a trench gate in trenches extending through a vertical drift region to a drain region. The trenches have field plates under the gate; the field plates are adjacent to the drift region and have a plurality of segments. A dielectric liner in the trenches separating the field plates from the drift region has a thickness great than a gate dielectric layer between the gate and the body. The dielectric liner is thicker on a lower segment of the field plate, at a bottom of the trenches, than an upper segment, immediately under the gate. The trench gate may be electrically isolated from the field plates, or may be connected to the upper segment. The segments of the field plates may be electrically isolated from each other or may be connected to each other in the trenches.
    Type: Grant
    Filed: May 7, 2015
    Date of Patent: March 29, 2016
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Hideaki Kawahara, Seetharaman Sridhar, Christopher Boguslaw Kocon, Simon John Molloy, Hong Yang
  • Patent number: 9230851
    Abstract: A method of fabricating a semiconductor device includes forming at least one trench from a top side of a semiconductor layer, wherein the trench is lined with a trench dielectric liner and filled by a first polysilicon layer. The surface of the trench dielectric liner is etched, wherein dips in the trench dielectric liner are formed relative to a top surface of the first polysilicon layer which results in forming a protrusion including the first polysilicon layer. The first polysilicon layer is etched to remove at least a portion of the protrusion. A second dielectric layer is formed over at least the trench after etching the first polysilicon layer. A second polysilicon layer is deposited. The second polysilicon layer is etched to remove it over the trench and provide a patterned second polysilicon layer on the top side of the semiconductor layer.
    Type: Grant
    Filed: February 7, 2014
    Date of Patent: January 5, 2016
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Simon John Molloy, Christopher Boguslaw Kocon, John Manning Savidge Neilson, Hong Yang, Seetharaman Sridhar, Hideaki Kawahara