Patents by Inventor Prasanna Khare
Prasanna Khare 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: 20140291749Abstract: A memory device may include a semiconductor substrate, and a memory transistor in the semiconductor substrate. The memory transistor may include source and drain regions in the semiconductor substrate and a channel region therebetween, and a gate stack. The gate stack may include a first dielectric layer over the channel region, a first diffusion barrier layer over the first dielectric layer, a first electrically conductive layer over the first diffusion barrier layer, a second dielectric layer over the first electrically conductive layer, a second diffusion barrier layer over the second dielectric layer, and a second electrically conductive layer over the second diffusion barrier layer. The first and second dielectric layers may include different dielectric materials, and the first diffusion barrier layer may be thinner than the second diffusion barrier layer.Type: ApplicationFiled: March 28, 2013Publication date: October 2, 2014Inventors: Prasanna KHARE, Stephane Allegret-Maret, Nicolas Loubet, Qing Liu, Hemanth Jagannathan, Lisa Edge, Kangguo Cheng, Bruce Doris
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Patent number: 8828851Abstract: An SOI substrate has a first region isolated from a second region. An SiGe layer is deposited on top of the SOI substrate in the second region. The substrate is subjected to a thermal oxidation process which drives in Ge from the SiGe layer to form an SiGeOI structure in the second region and an overlying oxide layer. If the SOI substrate is exposed in the first region, the thermal oxidation process further produces an oxide layer overlying the first region. The oxide layer(s) is(are) removed to expose an Si channel layer in the first region and an SiGe channel layer in the second region. Transistor gate stacks are formed over each of the Si channel layer and SiGe channel layer. Raised source and drain regions are formed from the Si channel layer and SiGe channel layer adjacent the transistor gate stacks.Type: GrantFiled: June 4, 2012Date of Patent: September 9, 2014Assignee: STMicroeletronics, Inc.Inventors: Nicolas Loubet, Prasanna Khare, Qing Liu
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Patent number: 8796147Abstract: Insulating layers can be formed over a semiconductor device region and etched in a manner that substantially reduces or prevents the amount of etching of the underlying channel region. A first insulating layer can be formed over a gate region and a semiconductor device region. A second insulating layer can be formed over the first insulating layer. A third insulating layer can be formed over the second insulating layer. A portion of the third insulating layer can be etched using a first etching process. A portion of the first and second insulating layers beneath the etched portion of the third insulating layer can be etched using at least a second etching process different from the first etching process.Type: GrantFiled: December 17, 2010Date of Patent: August 5, 2014Assignee: STMicroelectronics, Inc.Inventors: Nicolas Loubet, Qing Liu, Prasanna Khare
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Publication number: 20140175554Abstract: Channel-to-substrate leakage in a FinFET device can be prevented by inserting an insulating layer between the semiconducting channel (fin) and the substrate. Similarly, source/drain-to-substrate leakage in a FinFET device can be prevented by isolating the source/drain regions from the substrate by inserting an insulating layer between the source/drain regions and the substrate. The insulating layer isolates the conduction path from the substrate both physically and electrically, thus preventing current leakage. If an array of semiconducting fins is made up of a multi-layer stack, the bottom material can be removed thus yielding a fin array that is suspended above the silicon surface. A resulting gap underneath the remaining top fin material can then be filled in with oxide to better support the fins and to isolate the array of fins from the substrate. The resulting FinFET device is fully substrate-isolated in both the gate region and the source/drain regions.Type: ApplicationFiled: December 21, 2012Publication date: June 26, 2014Applicant: STMICROELECTRONICS , INC.Inventors: Nicolas Loubet, Prasanna Khare
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Patent number: 8759874Abstract: Despite improvements in FinFETs and strained silicon devices, transistors continue to suffer performance degradation as device dimensions shrink. These include, in particular, leakage of charge between the semiconducting channel and the substrate. An isolated channel FinFET device prevents channel-to-substrate leakage by inserting an insulating layer between the channel (fin) and the substrate. The insulating layer isolates the fin from the substrate both physically and electrically. To form the isolated FinFET device, an array of bi-layer fins can be grown epitaxially from the silicon surface, between nitride columns that provide localized insulation between adjacent fins. Then, the lower fin layer can be removed, while leaving the upper fin layer, thus yielding an interdigitated array of nitride columns and semiconducting fins suspended above the silicon surface. A resulting gap underneath the upper fin layer can then be filled in with oxide to isolate the array of fin channels from the substrate.Type: GrantFiled: November 30, 2012Date of Patent: June 24, 2014Assignee: STMicroelectronics, Inc.Inventors: Nicolas Loubet, Prasanna Khare
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Publication number: 20140151759Abstract: The presence of a facet or a void in an epitaxially grown crystal indicates that crystal growth has been interrupted by defects or by certain material boundaries. Faceting can be suppressed during epitaxial growth of silicon compounds that form source and drain regions of strained silicon transistors. It has been observed that faceting can occur when epitaxial layers of certain silicon compounds are grown adjacent to an oxide boundary, but faceting does not occur when the epitaxial layer is grown adjacent to a silicon boundary or adjacent to a nitride boundary. Because epitaxial growth of silicon compounds is often necessary in the vicinity of isolation trenches that are filled with oxide, techniques for suppression of faceting in these areas are of particular interest. One such technique, presented herein, is to line the isolation trenches with SiN to provide a barrier between the oxide and the region in which epitaxial growth is intended.Type: ApplicationFiled: December 3, 2012Publication date: June 5, 2014Applicant: STMicroelectronics, Inc.Inventors: Nicolas Loubet, Prasanna Khare, Qing Liu
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Publication number: 20140151746Abstract: Despite improvements in FinFETs and strained silicon devices, transistors continue to suffer performance degradation as device dimensions shrink. These include, in particular, leakage of charge between the semiconducting channel and the substrate. An isolated channel FinFET device prevents channel-to-substrate leakage by inserting an insulating layer between the channel (fin) and the substrate. The insulating layer isolates the fin from the substrate both physically and electrically. To form the isolated FinFET device, an array of bi-layer fins can be grown epitaxially from the silicon surface, between nitride columns that provide localized insulation between adjacent fins. Then, the lower fin layer can be removed, while leaving the upper fin layer, thus yielding an interdigitated array of nitride columns and semiconducting fins suspended above the silicon surface. A resulting gap underneath the upper fin layer can then be filled in with oxide to isolate the array of fin channels from the substrate.Type: ApplicationFiled: November 30, 2012Publication date: June 5, 2014Applicant: STMicroelectronics, Inc.Inventors: Nicolas Loubet, Prasanna Khare
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Patent number: 8703550Abstract: A shallow trench is formed to extend into a handle substrate of a semiconductor-on-insulator (SOI) layer. A dielectric liner stack of a dielectric metal oxide layer and a silicon nitride layer is formed in the shallow trench, followed by deposition of a shallow trench isolation fill portion. The dielectric liner stack is removed from above a top surface of a top semiconductor portion, followed by removal of a silicon nitride pad layer and an upper vertical portion of the dielectric metal oxide layer. A divot laterally surrounding a stack of a top semiconductor portion and a buried insulator portion is filled with a silicon nitride portion. Gate structures and source/drain structures are subsequently formed. The silicon nitride portion or the dielectric metal oxide layer functions as a stopping layer during formation of source/drain contact via holes, thereby preventing electrical shorts between source/drain contact via structures and the handle substrate.Type: GrantFiled: June 18, 2012Date of Patent: April 22, 2014Assignees: International Business Machines Corporation, STMicroelectronics, Inc., Commissariat a l'Energie Atomique et aux Energies AlternativesInventors: Bruce B. Doris, Shom Ponoth, Prasanna Khare, Qing Liu, Nicolas Loubet, Maud Vinet
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Publication number: 20140099773Abstract: A shallow trench is formed to extend into a handle substrate of a semiconductor-on-insulator (SOI) layer. A dielectric liner stack of a dielectric metal oxide layer and a silicon nitride layer is formed in the shallow trench, followed by deposition of a shallow trench isolation fill portion. The dielectric liner stack is removed from above a top surface of a top semiconductor portion, followed by removal of a silicon nitride pad layer and an upper vertical portion of the dielectric metal oxide layer. A divot laterally surrounding a stack of a top semiconductor portion and a buried insulator portion is filled with a silicon nitride portion. Gate structures and source/drain structures are subsequently formed. The silicon nitride portion or the dielectric metal oxide layer functions as a stopping layer during formation of source/drain contact via holes, thereby preventing electrical shorts between source/drain contact via structures and the handle substrate.Type: ApplicationFiled: December 4, 2013Publication date: April 10, 2014Applicants: INTERNATIONAL BUSINESS MACHINES CORPORATION, COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES, STMICROELECTRONICS, INC.Inventors: Bruce B. Doris, Shom Ponoth, Prasanna Khare, Qing Liu, Nicolas Loubet, Maud Vinet
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Publication number: 20140084372Abstract: A shallow trench is formed to extend into a handle substrate of a semiconductor-on-insulator (SOI) layer. A dielectric liner stack of a dielectric metal oxide layer and a silicon nitride layer is formed in the shallow trench, followed by deposition of a shallow trench isolation fill portion. The dielectric liner stack is removed from above a top surface of a top semiconductor portion, followed by removal of a silicon nitride pad layer and an upper vertical portion of the dielectric metal oxide layer. A divot laterally surrounding a stack of a top semiconductor portion and a buried insulator portion is filled with a silicon nitride portion. Gate structures and source/drain structures are subsequently formed. The silicon nitride portion or the dielectric metal oxide layer functions as a stopping layer during formation of source/drain contact via holes, thereby preventing electrical shorts between source/drain contact via structures and the handle substrate.Type: ApplicationFiled: December 4, 2013Publication date: March 27, 2014Applicants: INTERNATIONAL BUSINESS MACHINES CORPORATION, COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES, STMICROELECTRONICS, INC.Inventors: Bruce B. Doris, Shom Ponoth, Prasanna Khare, Qing Liu, Nicolas Loubet, Maud Vinet
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Publication number: 20140054715Abstract: A semiconductor device includes a semiconductor substrate having a channel region therein, a gate structure above the channel region, and source and drain regions on opposite sides of the gate structure. A respective contact is on each of the source and drain regions. At least one of the source and drain regions has an inclined upper contact surface with the respective contact. The inclined upper contact surface has at least a 50% greater area than would a corresponding flat contact surface.Type: ApplicationFiled: August 21, 2012Publication date: February 27, 2014Applicant: STMicroelectronics, Inc.Inventors: QING LIU, PRASANNA KHARE, NICOLAS LOUBET
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Publication number: 20140054699Abstract: An electronic device may include a substrate, a buried oxide (BOX) layer overlying the substrate, at least one semiconductor device overlying the BOX layer, and at least one shallow trench isolation (STI) region in the substrate and adjacent the at least one semiconductor device. The at least one STI region defines a sidewall surface with the substrate and may include an oxide layer lining a bottom portion of the sidewall surface, a nitride layer lining a top portion of the sidewall surface above the bottom portion, and an insulating material within the nitride and oxide layers.Type: ApplicationFiled: August 21, 2012Publication date: February 27, 2014Applicants: STMicroelectronics, Inc., COMMISSARIATE A ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES, INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: QING LIU, PRASANNA KHARE, NICOLAS LOUBET, SHOM PONOTH, MAUD VINET, BRUCE DORIS
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Publication number: 20140054698Abstract: An electronic device may include a substrate, a buried oxide (BOX) layer overlying the substrate, at least one semiconductor device overlying the BOX layer, and at least one STI region in the substrate and adjacent the at least one semiconductor device. The at least one STI region defines a sidewall surface with the substrate and may include a nitride layer lining a bottom portion of the sidewall surface, an oxide layer lining a top portion of the sidewall surface above the bottom portion, and an insulating material within the nitride and oxide layers.Type: ApplicationFiled: August 21, 2012Publication date: February 27, 2014Applicant: STMicroelectronics, Inc.Inventors: Qing Liu, Nicolas Loubet, Prasanna Khare
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Publication number: 20140054706Abstract: A multi-fin FINFET device may include a substrate and a plurality of semiconductor fins extending upwardly from the substrate and being spaced apart along the substrate. Each semiconductor fin may have opposing first and second ends and a medial portion therebetween, and outermost fins of the plurality of semiconductor fins may comprise an epitaxial growth barrier on outside surfaces thereof. The FINFET may further include at least one gate overlying the medial portions of the semiconductor fins, a plurality of raised epitaxial semiconductor source regions between the semiconductor fins adjacent the first ends thereof, and a plurality of raised epitaxial semiconductor drain regions between the semiconductor fins adjacent the second ends thereof.Type: ApplicationFiled: August 21, 2012Publication date: February 27, 2014Applicant: STMicroelectronics, Inc.Inventors: QING LIU, PRASANNA KHARE, NICOLAS LOUBET
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Publication number: 20130334651Abstract: A shallow trench is formed to extend into a handle substrate of a semiconductor-on-insulator (SOI) layer. A dielectric liner stack of a dielectric metal oxide layer and a silicon nitride layer is formed in the shallow trench, followed by deposition of a shallow trench isolation fill portion. The dielectric liner stack is removed from above a top surface of a top semiconductor portion, followed by removal of a silicon nitride pad layer and an upper vertical portion of the dielectric metal oxide layer. A divot laterally surrounding a stack of a top semiconductor portion and a buried insulator portion is filled with a silicon nitride portion. Gate structures and source/drain structures are subsequently formed. The silicon nitride portion or the dielectric metal oxide layer functions as a stopping layer during formation of source/drain contact via holes, thereby preventing electrical shorts between source/drain contact via structures and the handle substrate.Type: ApplicationFiled: June 18, 2012Publication date: December 19, 2013Applicants: International Business Machines Corporation, STMicroelectronic, Inc., Commissariat a l'energie atomique et aux energies alternativesInventors: Bruce B. Doris, Shom Ponoth, Prasanna Khare, Qing Liu, Nicolas Loubet, Maud Vinet
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Publication number: 20130277747Abstract: An embodiment of a transistor includes a body and a semiconductor region configured to stress a portion of the body. For example, stressing a channel of the transistor may increase the mobility of carriers in the channel, and thus may reduce the “on” resistance of the transistor. For example, the substrate, source/drain regions, or both the substrate and source/drain regions of a PFET may be doped to compressively stress the channel so as to increase the mobility of holes in the channel. Or, the substrate, source/drain regions, or both the substrate and source/drain regions of an NFET may be doped to tensile stress the channel so as to increase the mobility of electrons in the channel.Type: ApplicationFiled: April 24, 2012Publication date: October 24, 2013Applicant: STMICROELECTRONICS, INC.Inventors: Qing LIU, Nicolas LOUBET, Prasanna KHARE
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Publication number: 20130193514Abstract: An SOI substrate has a first region isolated from a second region. An SiGe layer is deposited on top of the SOI substrate in the second region. The substrate is subjected to a thermal oxidation process which drives in Ge from the SiGe layer to form an SiGeOI structure in the second region and an overlying oxide layer. If the SOI substrate is exposed in the first region, the thermal oxidation process further produces an oxide layer overlying the first region. The oxide layer(s) is(are) removed to expose an Si channel layer in the first region and an SiGe channel layer in the second region. Transistor gate stacks are formed over each of the Si channel layer and SiGe channel layer. Raised source and drain regions are formed from the Si channel layer and SiGe channel layer adjacent the transistor gate stacks.Type: ApplicationFiled: June 4, 2012Publication date: August 1, 2013Applicant: STMICROELECTRONICS, INC.Inventors: Nicolas Loubet, Prasanna Khare, Qing Liu
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Publication number: 20120267720Abstract: Methods and apparatus of integrating a buried-channel PMOS into a BiCMOS process. The apparatus comprises at least one bipolar transistor and at least one MOS device coupled to the at least one bipolar transistor, such that a gate of the at least one MOS device may be coupled to an emitter of the at least one bipolar transistor. The MOS device comprises a buried channel having mobility means, such as strained silicon for promoting hole mobility in the buried channel, and confinement means, such as a cap layer disposed proximate to the buried channel for limiting leakage of holes from the buried channel. The apparatus may be formed by exposing a substrate in a PMOS, forming a SiGe layer on the substrate, forming an oxide layer on the SiGe layer, masking the PMOS, and removing at least some of the oxide and at least some of the SiGe layer.Type: ApplicationFiled: July 2, 2012Publication date: October 25, 2012Applicant: STMicroelectronics Inc.Inventor: Prasanna Khare
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Patent number: 8237229Abstract: Methods and apparatus of integrating a buried-channel PMOS into a BiCMOS process. The apparatus comprises at least one bipolar transistor and at least one MOS device coupled to the at least one bipolar transistor, such that a gate of the at least one MOS device may be coupled to an emitter of the at least one bipolar transistor. The MOS device comprises a buried channel having mobility means, such as strained silicon for promoting hole mobility in the buried channel, and confinement means, such as a cap layer disposed proximate to the buried channel for limiting leakage of holes from the buried channel. The apparatus may be formed by exposing a substrate in a PMOS, forming a SiGe layer on the substrate, forming an oxide layer on the SiGe layer, masking the PMOS, and removing at least some of the oxide and at least some of the SiGe layer.Type: GrantFiled: May 22, 2008Date of Patent: August 7, 2012Assignee: STMicroelectronics Inc.Inventor: Prasanna Khare
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Publication number: 20120156847Abstract: Insulating layers can be formed over a semiconductor device region and etched in a manner that substantially reduces or prevents the amount of etching of the underlying channel region. A first insulating layer can be formed over a gate region and a semiconductor device region. A second insulating layer can be formed over the first insulating layer. A third insulating layer can be formed over the second insulating layer. A portion of the third insulating layer can be etched using a first etching process. A portion of the first and second insulating layers beneath the etched portion of the third insulating layer can be etched using at least a second etching process different from the first etching process.Type: ApplicationFiled: December 17, 2010Publication date: June 21, 2012Applicant: STMicroelectronics Inc.Inventors: Nicolas Loubet, Qing Liu, Prasanna Khare