Patents by Inventor Niraj Ranjan

Niraj Ranjan 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: 20220109068
    Abstract: A semiconductor device includes: a trench formed in a surface of a semiconductor substrate and extending lengthwise in a direction parallel to the surface; a body region adjoining the trench; a source region adjoining the trench above the body region; a drift region adjoining the trench below the body region; a field electrode in a lower part of the trench and separated from the substrate; and a gate electrode in an upper part of the trench and separated from the substrate and the field electrode. A first section of the field electrode is buried below the gate electrode in the trench. A second section of the field electrode transitions upward from the first section in a direction toward the surface. The separation between the second section and the gate electrode is greater than or equal to the separation between the first section and the gate electrode.
    Type: Application
    Filed: December 16, 2021
    Publication date: April 7, 2022
    Inventors: Ashita Mirchandani, Robert Haase, Tim Henson, Ling Ma, Niraj Ranjan
  • Patent number: 11217690
    Abstract: A semiconductor device includes: a trench formed in a surface of a semiconductor substrate and extending lengthwise in a direction parallel to the surface; a body region adjoining the trench; a source region adjoining the trench above the body region; a drift region adjoining the trench below the body region; a field electrode in a lower part of the trench and separated from the substrate; and a gate electrode in an upper part of the trench and separated from the substrate and the field electrode. A first section of the field electrode is buried below the gate electrode in the trench. A second section of the field electrode transitions upward from the first section in a direction toward the surface. The separation between the second section and the gate electrode is greater than or equal to the separation between the first section and the gate electrode.
    Type: Grant
    Filed: September 16, 2019
    Date of Patent: January 4, 2022
    Assignee: Infineon Technologies Austria AG
    Inventors: Ashita Mirchandani, Robert Haase, Tim Henson, Ling Ma, Niraj Ranjan
  • Publication number: 20210083096
    Abstract: A semiconductor device includes: a trench formed in a surface of a semiconductor substrate and extending lengthwise in a direction parallel to the surface; a body region adjoining the trench; a source region adjoining the trench above the body region; a drift region adjoining the trench below the body region; a field electrode in a lower part of the trench and separated from the substrate; and a gate electrode in an upper part of the trench and separated from the substrate and the field electrode. A first section of the field electrode is buried below the gate electrode in the trench. A second section of the field electrode transitions upward from the first section in a direction toward the surface. The separation between the second section and the gate electrode is greater than or equal to the separation between the first section and the gate electrode.
    Type: Application
    Filed: September 16, 2019
    Publication date: March 18, 2021
    Inventors: Ashita Mirchandani, Robert Haase, Tim Henson, Ling Ma, Niraj Ranjan
  • Patent number: 10879230
    Abstract: A Schottky diode includes a cathode terminal in a high voltage region of a semiconductor die, an anode terminal in a low voltage region of the semiconductor die, where the anode terminal and the cathode terminal are separated by a junction isolation termination situated between the high voltage region and the low voltage region. The Schottky diode includes a junction barrier Schottky diode or a trench metal-oxide-semiconductor (MOS) Schottky diode. The junction isolation termination includes pzener rings. The semiconductor die includes a substrate of a first conductivity type, an epitaxial layer of a second conductivity type situated on the substrate, a well region of the second conductivity type situated in the epitaxial layer in the high voltage region, and coupled to the cathode terminal, a Schottky barrier situated on the epitaxial layer in the low voltage region, and coupled to the anode terminal.
    Type: Grant
    Filed: June 17, 2016
    Date of Patent: December 29, 2020
    Assignee: Infineon Technologies Americas Corp.
    Inventors: Donald He, Niraj Ranjan, Siddharth Kiyawat, Min Fang
  • Patent number: 9991377
    Abstract: According to an exemplary implementation, a field-effect transistor (FET) includes first and second gate trenches extending to a drift region of a first conductivity type. The FET also includes a base region of a second conductivity type that is situated between the first and second gate trenches. A ruggedness enhancement region is situated between the first and second gate trenches, where the ruggedness enhancement region is configured to provide an enhanced avalanche current path from a drain region to the base region when the FET is in an avalanche condition. The enhanced avalanche current path is away from the first and second gate trenches. The ruggedness enhancement region can be of the second conductivity type that includes a higher dopant concentration than the base region. Furthermore, the ruggedness enhancement region can be extending below the first and second gate trenches.
    Type: Grant
    Filed: March 11, 2013
    Date of Patent: June 5, 2018
    Assignee: Infineon Technologies Americas Corp.
    Inventors: Ashita Mirchandani, Timothy D. Henson, Ling Ma, Niraj Ranjan
  • Patent number: 9859407
    Abstract: There are disclosed herein various implementations of an insulated-gate bipolar transistor (IGBT) with buried depletion electrode. Such an IGBT may include a collector at a bottom surface of a semiconductor substrate, a drift region having a first conductivity type situated over the collector, and a base layer having a second conductivity type opposite the first conductivity type situated over the drift region. The IGBT also includes a plurality of deep insulated trenches with a buried depletion electrode and at least one gate electrode disposed therein. In addition, the IGBT includes an active cell including an emitter adjacent the gate electrode, and an implant zone, situated between adjacent deep insulated trenches. The implant zone is formed below the base layer and has the first conductivity type. In one implementation, the IGBT may also include a dummy cell neighboring the active cell.
    Type: Grant
    Filed: March 23, 2016
    Date of Patent: January 2, 2018
    Assignee: Infineon Technologies Americas Corp.
    Inventors: Yi Tang, Niraj Ranjan, Chiu Ng
  • Publication number: 20170365595
    Abstract: A Schottky diode includes a cathode terminal in a high voltage region of a semiconductor die, an anode terminal in a low voltage region of the semiconductor die, where the anode terminal and the cathode terminal are separated by a junction isolation termination situated between the high voltage region and the low voltage region. The Schottky diode includes a junction barrier Schottky diode or a trench metal-oxide-semiconductor (MOS) Schottky diode. The junction isolation termination includes pzener rings. The semiconductor die includes a substrate of a first conductivity type, an epitaxial layer of a second conductivity type situated on the substrate, a well region of the second conductivity type situated in the epitaxial layer in the high voltage region, and coupled to the cathode terminal, a Schottky barrier situated on the epitaxial layer in the low voltage region, and coupled to the anode terminal.
    Type: Application
    Filed: June 17, 2016
    Publication date: December 21, 2017
    Inventors: Donald He, Niraj Ranjan, Siddharth Kiyawat, Min Fang
  • Patent number: 9818743
    Abstract: Disclosed is a power semiconductor device that includes a plurality of source trenches and adjacent source regions. The plurality of source trenches extend from a top surface of a semiconductor substrate into the semiconductor substrate. The power semiconductor device further includes a plurality of gate trenches that extend from the top of the semiconductor substrate into the semiconductor substrate, and are arranged in hexagonal or zigzag patterns. A contiguous formation is created by the plurality of gate trenches, and the plurality of gate trenches separate the plurality of source trenches from one another.
    Type: Grant
    Filed: June 9, 2014
    Date of Patent: November 14, 2017
    Assignee: INFINEON TECHNOLOGIES AMERICAS CORP.
    Inventors: Kapil Kelkar, Timothy D. Henson, Ling Ma, Hugo Burke, Niraj Ranjan, Alain Charles
  • Publication number: 20170279449
    Abstract: A semiconductor device includes a low voltage region, a high voltage region monolithically integrated with the low voltage region in a semiconductor substrate, where the low voltage region is electrically coupled to the high voltage region through a capacitive isolation barrier, where the high voltage region is structurally isolated from the low voltage region by an isolation structure. The isolation structure includes a junction termination structure, a deep trench structure, or a reduced surface field (RESURF) structure. The isolation structure forms an isolation ring substantially enclosing the high voltage region in the semiconductor substrate. The low voltage region is configured to provide a differential signal to the high voltage region through the capacitive isolation barrier. The high voltage region is configured to receive a differential signal from the low voltage region through the capacitive isolation barrier so as to level shift the differential signal.
    Type: Application
    Filed: March 25, 2016
    Publication date: September 28, 2017
    Inventors: Min Fang, Niraj Ranjan, Siddharth Kiyawat, Donald He, Praveen Kumar Kalsani
  • Publication number: 20170213909
    Abstract: According to an embodiment of a method for fabricating a trench field-effect transistor (trench FET), the method includes: forming a trench in a semiconductor substrate of a first conductivity type, the trench including sidewalls which taper from a wider, top portion of the trench to a narrower, bottom portion of the trench; forming a gate dielectric in the trench, the gate dielectric having substantially the same thickness in the wider, top portion of the trench as in the narrower, bottom portion of the trench; forming a gate electrode in the trench and separated from the semiconductor substrate by the gate dielectric; and forming a channel region of a second conductivity type in the semiconductor substrate after forming the trench and the gate dielectric, the channel region being disposed adjacent the trench. Trench FETs formed by the method are also disclosed.
    Type: Application
    Filed: April 10, 2017
    Publication date: July 27, 2017
    Inventors: Timothy D. Henson, Ling Ma, Hugo Burke, David P. Jones, Kapil Kelkar, Niraj Ranjan, Igor Bol
  • Patent number: 9653597
    Abstract: Disclosed is a method for fabricating a shallow and narrow trench field-effect transistor (trench FET). The method includes forming a trench within a semiconductor substrate of a first conductivity type, the trench including sidewalls and a bottom portion. The method further includes forming a substantially uniform gate dielectric in the trench, and forming a gate electrode within said trench and over said gate dielectric. The method also includes doping the semiconductor substrate to form a channel region of a second conductivity type after forming the trench. In one embodiment, the doping step is performed after forming the gate dielectric and after forming the gate electrode. In another embodiment, the doping step is performed after forming the gate dielectric, but prior to forming the gate electrode. Structures formed by the invention's method are also disclosed.
    Type: Grant
    Filed: May 20, 2010
    Date of Patent: May 16, 2017
    Assignee: Infineon Technologies Americas Corp.
    Inventors: Timothy D. Henson, Ling Ma, Hugo Burke, David P. Jones, Kapil Kelkar, Niraj Ranjan, Igor Bol
  • Patent number: 9590096
    Abstract: In one implementation, a vertical field-effect transistor (FET) includes a substrate having a drift region situated over a drain, a body region situated over the drift region and having source diffusions formed therein, a gate trench extending through the body region, and channel regions adjacent the gate trench. The channel regions are spaced apart along the gate trench by respective deep body implants. Each of the deep body implants is situated approximately under at least one of the source diffusions, and has a depth greater than a depth of the gate trench.
    Type: Grant
    Filed: November 16, 2015
    Date of Patent: March 7, 2017
    Assignee: Infineon Technologies Americas Corp.
    Inventors: Harsh Naik, Timothy D. Henson, Niraj Ranjan
  • Patent number: 9496378
    Abstract: There are disclosed herein various implementations of an insulated gate bipolar transistor (IGBT) with buried emitter electrodes. Such an IGBT may include a collector at a bottom surface of a semiconductor substrate, a drift region having a first conductivity type situated over the collector, and a base layer having a second conductivity type opposite the first conductivity type situated over the drift region. In addition, such an IGBT may include deep insulated trenches extending from a semiconductor surface above the base layer, into the drift region, each of the deep insulated trenches having a buried emitter electrode disposed therein. The IGBT may further include an active cell including an emitter, a gate trench with a gate electrode disposed therein, and an implant zone situated, between adjacent deep insulated trenches. The implant zone is formed below the base layer and has the first conductivity type.
    Type: Grant
    Filed: January 20, 2016
    Date of Patent: November 15, 2016
    Assignee: Infineon Technologies Americas Corp.
    Inventors: Yi Tang, Niraj Ranjan, Chiu Ng
  • Publication number: 20160204238
    Abstract: There are disclosed herein various implementations of an insulated-gate bipolar transistor (IGBT) with buried depletion electrode. Such an IGBT may include a collector at a bottom surface of a semiconductor substrate, a drift region having a first conductivity type situated over the collector, and a base layer having a second conductivity type opposite the first conductivity type situated over the drift region. The IGBT also includes a plurality of deep insulated trenches with a buried depletion electrode and at least one gate electrode disposed therein. In addition, the IGBT includes an active cell including an emitter adjacent the gate electrode, and an implant zone, situated between adjacent deep insulated trenches. The implant zone is formed below the base layer and has the first conductivity type. In one implementation, the IGBT may also include a dummy cell neighboring the active cell.
    Type: Application
    Filed: March 23, 2016
    Publication date: July 14, 2016
    Inventors: Yi Tang, Niraj Ranjan, Chiu Ng
  • Publication number: 20160172295
    Abstract: In one implementation, a power field-effect transistor (FET) having a reduced gate resistance includes a drain, a source, a gate, and a gate contact including a gate pad, a gate highway, and multiple gate buses. The gate buses are formed from a first metal layer having a first thickness, while the gate pad and the gate highway each include a metal stack including the first metal layer and a second metal layer. The second metal layer has a second thickness substantially greater than the first thickness, thereby reducing the gate resistance of the power FET.
    Type: Application
    Filed: December 1, 2015
    Publication date: June 16, 2016
    Inventors: Alex Lollio, Timothy D. Henson, Ling Ma, Harsh Naik, Niraj Ranjan
  • Publication number: 20160172484
    Abstract: In one implementation, a vertical field-effect transistor (FET) includes a substrate having a drift region situated over a drain, a body region situated over the drift region and having source diffusions formed therein, a gate trench extending through the body region, and channel regions adjacent the gate trench. The channel regions are spaced apart along the gate trench by respective deep body implants. Each of the deep body implants is situated approximately under at least one of the source diffusions, and has a depth greater than a depth of the gate trench.
    Type: Application
    Filed: November 16, 2015
    Publication date: June 16, 2016
    Inventors: Harsh Naik, Timothy D. Henson, Niraj Ranjan
  • Publication number: 20160155832
    Abstract: There are disclosed herein various implementations of an insulated gate bipolar transistor (IGBT) with buried emitter electrodes. Such an IGBT may include a collector at a bottom surface of a semiconductor substrate, a drift region having a first conductivity type situated over the collector, and a base layer having a second conductivity type opposite the first conductivity type situated over the drift region. In addition, such an IGBT may include deep insulated trenches extending from a semiconductor surface above the base layer, into the drift region, each of the deep insulated trenches having a buried emitter electrode disposed therein. The IGBT may further include an active cell including an emitter, a gate trench with a gate electrode disposed therein, and an implant zone situated, between adjacent deep insulated trenches. The implant zone is formed below the base layer and has the first conductivity type.
    Type: Application
    Filed: January 20, 2016
    Publication date: June 2, 2016
    Inventors: Yi Tang, Niraj Ranjan, Chiu Ng
  • Patent number: 9299819
    Abstract: There are disclosed herein various implementations of an insulated-gate bipolar transistor (IGBT) with buried depletion electrode. Such an IGBT may include a collector at a bottom surface of a semiconductor substrate, a drift region having a first conductivity type situated over the collector, and a base layer having a second conductivity type opposite the first conductivity type situated over the drift region. The IGBT also includes a plurality of deep insulated trenches with a buried depletion electrode and at least one gate electrode disposed therein. In addition, the IGBT includes an active cell including an emitter adjacent the gate electrode, and an implant zone, situated between adjacent deep insulated trenches. The implant zone is formed below the base layer and has the first conductivity type. In one implementation, the IGBT may also include a dummy cell neighboring the active cell.
    Type: Grant
    Filed: March 8, 2013
    Date of Patent: March 29, 2016
    Assignee: Infineon Technologies Americas Corp.
    Inventors: Yi Tang, Niraj Ranjan, Chiu Ng
  • Patent number: 9257983
    Abstract: According to an exemplary implementation, a level shifter includes a low voltage circuit and a high voltage circuit. The low voltage circuit is configured to provide a differential signal to the high voltage circuit through a capacitive isolation barrier. The high voltage circuit is configured to receive the differential signal from the low voltage circuit through the capacitive isolation barrier so as to level shift the differential signal from a first ground of the low voltage circuit to a second ground of the high voltage circuit. The high voltage circuit is further configured to provide a feedback signal to the low voltage circuit through the capacitive isolation barrier. The low voltage circuit can be configured to receive the feedback signal from the low voltage circuit between edges of the differential signal.
    Type: Grant
    Filed: October 30, 2014
    Date of Patent: February 9, 2016
    Assignee: Infineon Technologies Americas Corp.
    Inventors: Min Fang, Massimo Grasso, Niraj Ranjan
  • Patent number: 9245985
    Abstract: There are disclosed herein various implementations of an insulated gate bipolar transistor (IGBT) with buried emitter electrodes. Such an IGBT may include a collector at a bottom surface of a semiconductor substrate, a drift region having a first conductivity type situated over the collector, and a base layer having a second conductivity type opposite the first conductivity type situated over the drift region. In addition, such an IGBT may include deep insulated trenches extending from a semiconductor surface above the base layer, into the drift region, each of the deep insulated trenches having a buried emitter electrode disposed therein. The IGBT may further include an active cell including an emitter, a gate trench with a gate electrode disposed therein, and an implant zone situated, between adjacent deep insulated trenches. The implant zone is formed below the base layer and has the first conductivity type.
    Type: Grant
    Filed: March 8, 2013
    Date of Patent: January 26, 2016
    Assignee: Infineon Technologies Americas Corp.
    Inventors: Yi Tang, Niraj Ranjan, Chiu Ng