Patents by Inventor Sujit Banerjee
Sujit Banerjee 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).
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Publication number: 20110073942Abstract: In one embodiment, a high voltage field-effect transistor (HVFET) includes a field oxide layer that covers a first well region, the field oxide layer having a first thickness and extending in a second lateral direction from a drain region to near a second well region. A gate oxide covers a channel region and has a second dimension in a first lateral direction. A gate extends in the second lateral direction from the source region to over a portion of the field oxide layer, the gate being insulated from the channel region by the gate oxide, the gate extending in the first lateral dimension over an inactive area of the HVFET beyond the second dimension of the gate oxide, the gate being insulated from the first and second well regions over the inactive area by the field oxide layer.Type: ApplicationFiled: September 29, 2009Publication date: March 31, 2011Applicant: Power Integrations, Inc.Inventors: Sujit Banerjee, Vijay Parthasarathy
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Publication number: 20110042726Abstract: A high-voltage device structure comprises a resistor coupled to a tap transistor that includes a JFET in a configuration wherein a voltage provided at a terminal of the JFET is substantially proportional to an external voltage when the external voltage is less than a pinch-off voltage of the JFET. The voltage provided at the terminal being substantially constant when the external voltage is greater than the pinch-off voltage. One end of the resistor is substantially at the external voltage when the external voltage is greater than the pinch-off voltage. When the external voltage is negative, the resistor limits current injected into the substrate. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.Type: ApplicationFiled: August 20, 2009Publication date: February 24, 2011Applicant: Power Integrations, Inc.Inventors: Sujit Banerjee, Vijay Parthasarathy
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Patent number: 7871882Abstract: In one embodiment, a method comprises forming an epitaxial layer over a substrate of an opposite conductivity type, the epitaxial layer being separated by a buffer layer having a doping concentration that is substantially constant in a vertical direction down to the buffer layer. A pair of spaced-apart trenches is formed in the epitaxial layer from a top surface of the epitaxial layer down at least into the buffer layer. A dielectric material is formed in the trenches over the first and second sidewall portions. Source/collector and body regions of are formed at the top of the epitaxial layer, the body region separating the source/collector region of the pillar from a drift region of the epitaxial layer that extends from the body region to the buffer layer. An insulated gate member is then formed in each of the trenches adjacent to and insulated from the body region.Type: GrantFiled: December 20, 2008Date of Patent: January 18, 2011Assignee: Power Integrations, Inc.Inventors: Vijay Parthasarathy, Sujit Banerjee
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Patent number: 7859037Abstract: In one embodiment, a transistor fabricated on a semiconductor die is arranged into sections of elongated transistor segments. The sections are arranged in rows and columns substantially across the semiconductor die. Adjacent sections in a row or a column are oriented such that the length of the transistor segments in a first one of the adjacent sections extends in a first direction, and the length of the transistor segments in a second one of the adjacent sections extends in a second direction, the first direction being substantially orthogonal to the second direction. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.Type: GrantFiled: February 16, 2007Date of Patent: December 28, 2010Assignee: Power Integrations, Inc.Inventors: Vijay Parthasarathy, Sujit Banerjee, Martin H. Manley
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Publication number: 20100301412Abstract: In one embodiment, a power integrated circuit device includes a main lateral high-voltage field-effect transistor (HVFET) and an adjacently-located lateral sense FET, both of which are formed on a high-resistivity substrate. A sense resistor is formed in a well region disposed in an area of the substrate between the HVFET and the sense FET. A parasitic substrate resistor is formed in parallel electrical connection with the sense resistor between the source regions of the HVFET and the sense FET. Both transistor devices share common drain and gate electrodes. When the main lateral HVFET and the sense FET are in an on-state, a voltage potential is produced at the second source metal layer that is proportional to a first current flowing through the lateral HVFET.Type: ApplicationFiled: May 29, 2009Publication date: December 2, 2010Applicant: Power Integrations, Inc.Inventors: Vijay Parthasarathy, Sujit Banerjee
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Patent number: 7791132Abstract: A high-voltage transistor includes first and second trenches that define a mesa in a semiconductor substrate. First and second field plate members are respectively disposed in the first and second trenches, with each of the first and second field plate members being separated from the mesa by a dielectric layer. The mesa includes a plurality of sections, each section having a substantially constant doping concentration gradient, the gradient of one section being at least 10% greater than the gradient of another section. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.Type: GrantFiled: January 4, 2010Date of Patent: September 7, 2010Assignee: Power Integrations, Inc.Inventors: Sujit Banerjee, Donald Ray Disney
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Publication number: 20100155773Abstract: In one embodiment, a power transistor device comprises a substrate that forms a PN junction with an overlying buffer layer. The power transistor device further includes a first region, a drift region that adjoins a top surface of the buffer layer, and a body region. The body region separates the first region from the drift region. First and second dielectric regions respectively adjoin opposing lateral sidewall portions of the drift region. The dielectric regions extend in a vertical direction from at least just beneath the body region down at least into the buffer layer. First and second field plates are respectively disposed in the first and second dielectric regions. A trench gate that controls forward conduction is disposed above the dielectric region adjacent to and insulated from the body region.Type: ApplicationFiled: December 23, 2008Publication date: June 24, 2010Applicant: Power Integrations, Inc.Inventors: Vijay Parthasarathy, Sujit Banerjee
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Publication number: 20100155831Abstract: In one embodiment, a power transistor device comprises a substrate of a first conductivity type that forms a PN junction with an overlying buffer layer of a second conductivity type. The power transistor device further includes a first region of the second conductivity type, a drift region of the second conductivity type that adjoins a top surface of the buffer layer, and a body region of the first conductivity type. The body region separates the first region from the drift region. First and second dielectric regions respectively adjoin opposing lateral sidewall portions of the drift region. The dielectric regions extend in a vertical direction from at least just beneath the body region down at least into the buffer layer. A trench gate that controls forward conduction is disposed above the dielectric region adjacent to and insulated from the body region.Type: ApplicationFiled: December 20, 2008Publication date: June 24, 2010Applicant: Power Integrations, Inc.Inventors: Vijay Parthasarathy, Sujit Banerjee
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Publication number: 20100159649Abstract: In one embodiment, a method comprises forming an epitaxial layer over a substrate of an opposite conductivity type, the epitaxial layer being separated by a buffer layer having a doping concentration that is substantially constant in a vertical direction down to the buffer layer. A pair of spaced-apart trenches is formed in the epitaxial layer from a top surface of the epitaxial layer down at least into the buffer layer. A dielectric material is formed in the trenches over the first and second sidewall portions. Source/collector and body regions of are formed at the top of the epitaxial layer, the body region separating the source/collector region of the pillar from a drift region of the epitaxial layer that extends from the body region to the buffer layer. An insulated gate member is then formed in each of the trenches adjacent to and insulated from the body region.Type: ApplicationFiled: December 20, 2008Publication date: June 24, 2010Applicant: Power Integrations, Inc.Inventors: Vijay Parthasarathy, Sujit Banerjee
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Patent number: 7718075Abstract: Methods are provided for treating suspensions of particles to improve the drainage rate and/or the solids content of flocs of the particles. The method includes the steps of (i) providing a suspension which comprises particles in a fluid; (ii) adding a cyclodextrin compound to the suspension; and (iii) dewatering the suspension by removing at least a portion of the fluid to form a cake comprising the particles. The cyclodextrin compound desirably is added in an amount effective to increase the dewatering rate of the flocs, to increase the solids content, or both, over that rate, solids content, or both, that would be obtained without the addition of the cyclodextrin compound. The suspension may be, for example, a biological or non-biological sludge, or a suspension of pulp fibers, such as in a pulping or papermaking process.Type: GrantFiled: February 14, 2006Date of Patent: May 18, 2010Assignee: Georgia Tech Research CorporationInventor: Sujit Banerjee
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Publication number: 20100109077Abstract: A high-voltage transistor includes first and second trenches that define a mesa in a semiconductor substrate. First and second field plate members are respectively disposed in the first and second trenches, with each of the first and second field plate members being separated from the mesa by a dielectric layer. The mesa includes a plurality of sections, each section having a substantially constant doping concentration gradient, the gradient of one section being at least 10% greater than the gradient of another section. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.Type: ApplicationFiled: January 4, 2010Publication date: May 6, 2010Applicant: Power Integrations, Inc.Inventors: Sujit Banerjee, Donald Ray Disney
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Publication number: 20100065903Abstract: In one embodiment, a vertical HVFET includes a pillar of semiconductor material a pillar of semiconductor material arranged in a loop layout having at least two substantially parallel and substantially linear fillet sections each having a first width, and at least two rounded sections, the rounded sections having a second width narrower than the first width, a source region of a first conductivity type being disposed at or near a top surface of the pillar, and a body region of a second conductivity type being disposed in the pillar beneath the source region. First and second dielectric regions are respectively disposed on opposite sides of the pillar, the first dielectric region being laterally surrounded by the pillar, and the second dielectric region laterally surrounding the pillar. First and second field plates are respectively disposed in the first and second dielectric regions.Type: ApplicationFiled: September 18, 2008Publication date: March 18, 2010Applicant: Power Integrations, Inc.Inventors: Vijay Parthasarathy, Sujit Banerjee, Lin Zhu
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Patent number: 7648879Abstract: A high-voltage transistor includes first and second trenches that define a mesa in a semiconductor substrate. First and second field plate members are respectively disposed in the first and second trenches, with each of the first and second field plate members being separated from the mesa by a dielectric layer. The mesa includes a plurality of sections, each section having a substantially constant doping concentration gradient, the gradient of one section being at least 10% greater than the gradient of another section. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.Type: GrantFiled: October 24, 2008Date of Patent: January 19, 2010Assignee: Power Integrations, Inc.Inventors: Sujit Banerjee, Donald Ray Disney
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Publication number: 20090061585Abstract: A high-voltage transistor includes first and second trenches that define a mesa in a semiconductor substrate. First and second field plate members are respectively disposed in the first and second trenches, with each of the first and second field plate members being separated from the mesa by a dielectric layer. The mesa includes a plurality of sections, each section having a substantially constant doping concentration gradient, the gradient of one section being at least 10% greater than the gradient of another section. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.Type: ApplicationFiled: October 24, 2008Publication date: March 5, 2009Applicant: Power Integrations, Inc.Inventors: Sujit Banerjee, Donald Ray Disney
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Patent number: 7459366Abstract: A high-voltage transistor includes first and second trenches that define a mesa in a semiconductor substrate. First and second field plate members are respectively disposed in the first and second trenches, with each of the first and second field plate members being separated from the mesa by a dielectric layer. The mesa includes a plurality of sections, each section having a substantially constant doping concentration gradient, the gradient of one section being at least 10% greater than the gradient of another section. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.Type: GrantFiled: December 19, 2007Date of Patent: December 2, 2008Assignee: Power Integrations, Inc.Inventors: Sujit Banerjee, Donald Ray Disney
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Publication number: 20080197406Abstract: In one embodiment, a semiconductor device includes a main vertical field-effect transistor (FET) and a sensing FET. The main vertical FET and the sense FET are both formed on a pillar of semiconductor material. Both share an extended drain region formed in the pillar above the substrate, and first and second gate members formed in a dielectric on opposite sides of the pillar. The source regions of the main vertical FET and the sensing FET are separated and electrically isolated in a first lateral direction. In operation, the sensing FET samples a small portion of a current that flows in the main vertical FET. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.Type: ApplicationFiled: February 16, 2007Publication date: August 21, 2008Applicant: Power Integrations, Inc.Inventors: Vijay Parthasarathy, Sujit Banerjee, Martin H. Manley
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Publication number: 20080197397Abstract: In one embodiment, a transistor fabricated on a semiconductor die is arranged into sections of elongated transistor segments. The sections are arranged in rows and columns substantially across the semiconductor die. Adjacent sections in a row or a column are oriented such that the length of the transistor segments in a first one of the adjacent sections extends in a first direction, and the length of the transistor segments in a second one of the adjacent sections extends in a second direction, the first direction being substantially orthogonal to the second direction. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.Type: ApplicationFiled: February 16, 2007Publication date: August 21, 2008Applicant: Power Integrations, Inc.Inventors: Vijay Parthasarathy, Sujit Banerjee, Martin H. Manley
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Publication number: 20080149288Abstract: Methods are provided for altering the tack of an adhesive material by contacting the adhesive material with an amount of a cyclodextrin compound effective to reduce the tack of the adhesive material. In a preferred embodiment, the method is for altering the tack of adhesive contaminants in a process fluid, which includes the steps of providing a process fluid in which are dispersed contaminant particles which comprises one or more adhesive materials (such as pitch, pressure sensitive adhesives, hot melts, latexes, binders, and combinations thereof); and adding to the process an amount of a cyclodextrin compound effective to reduce the tack of the adhesive material. The process fluid can be in a process stream in a pulp and paper mill.Type: ApplicationFiled: February 14, 2006Publication date: June 26, 2008Applicant: GEORGIA TECH RESEARCH CORPORATIONInventor: Sujit Banerjee
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Publication number: 20080135194Abstract: Methods are provided for treating suspensions of particles to improve the drainage rate and/or the solids content of flocs of the particles. The method includes the steps of (i) providing a suspension which comprises particles in a fluid; (ii) adding a cyclodextrin compound to the suspension; and (iii) dewatering the suspension by removing at least a portion of the fluid to form a cake comprising the particles. The cyclodextrin compound desirably is added in an amount effective to increase the dewatering rate of the flocs, to increase the solids content, or both, over that rate, solids content, or both, that would be obtained without the addition of the cyclodextrin compound. The suspension may be, for example, a biological or non-biological sludge, or a suspension of pulp fibers, such as in a pulping or papermaking process.Type: ApplicationFiled: February 14, 2006Publication date: June 12, 2008Applicant: GEORGIA TECH RESEARCH CORPORATIONInventor: Sujit Banerjee
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Patent number: 7374688Abstract: Exposing sludge to underwater, high-intensity sparks, to increase cake solids, provide faster settling, and increase the rate of dewatering.Type: GrantFiled: August 8, 2005Date of Patent: May 20, 2008Assignee: Georgia Tech Research CorporationInventor: Sujit Banerjee