Patents by Inventor Herbert L. Ho
Herbert L. Ho 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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Patent number: 7816728Abstract: The present invention provides two-transistor silicon-oxide-nitride-oxide-semiconductor (2-Tr SONOS) non-volatile memory cells with randomly accessible storage locations as well as method of fabricating the same. In one embodiment, a 2-Tr SONOS cell is provided in which the select transistor is located within a trench structure having trench depth from 1 to 2 ?m and the memory transistor is located on a surface of a semiconductor substrate adjoining the trench structure. In another embodiment, a 2-Tr SONOS memory cell is provided in which both the select transistor and the memory transistor are located within a trench structure having the depth mentioned above.Type: GrantFiled: April 12, 2005Date of Patent: October 19, 2010Assignee: International Business Machines CorporationInventors: Herbert L. Ho, Jack A. Mandelman, Tak H. Ning, Yoichi Otani
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Patent number: 7807526Abstract: The present invention provides two-transistor silicon-oxide-nitride-oxide-semiconductor (2-Tr SONOS) non-volatile memory cells with randomly accessible storage locations as well as method of fabricating the same. In one embodiment, a 2-Tr SONOS cell is provided in which the select transistor is located with a trench structure having trench depth from 1 to 2 ?m and the memory transistor is located on a surface of a semiconductor substrate adjoining the trench structure. In another embodiment, a 2-Tr SONOS memory cell is provided in which both the select transistor and the memory transistor are located within a trench structure having the depth mentioned above.Type: GrantFiled: October 30, 2007Date of Patent: October 5, 2010Assignee: International Business Machines CorporationInventors: Herbert L. Ho, Jack A. Mandelman, Tak H. Ning, Yoichi Otani
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Patent number: 7791124Abstract: A bottle shaped trench for an SOI capacitor is formed by a simple processing sequence. A non-conformal dielectric layer with an optional conformal dielectric diffusion barrier layer underneath is formed on sidewalls of a deep trench. Employing an isotropic etch, the non-conformal dielectric layer is removed from a bottom portion of the deep trench, leaving a dielectric spacer covering sidewalls of the buried insulator layer and the top semiconductor layer. The bottom portion of the deep trench is expanded to form a bottle shaped trench, and a buried plated is formed underneath the buried insulator layer. The dielectric spacer may be recessed during formation of a buried strap to form a graded thickness dielectric collar around the upper portion of an inner electrode. Alternately, the dielectric spacer may be removed prior to formation of a buried strap.Type: GrantFiled: May 21, 2008Date of Patent: September 7, 2010Assignee: International Business Machines CorporationInventors: Kangguo Cheng, Herbert L. Ho, Paul C. Parries, Geng Wang
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Publication number: 20100207683Abstract: The present invention provides a “collector-less” silicon-on-insulator (SOI) bipolar junction transistor (BJT) that has no impurity-doped collector. Instead, the inventive vertical SOI BJT uses a back gate-induced, minority carrier inversion layer as the intrinsic collector when it operates. In accordance with the present invention, the SOI substrate is biased such that an inversion layer is formed at the bottom of the base region serving as the collector. The advantage of such a device is its CMOS-like process. Therefore, the integration scheme can be simplified and the manufacturing cost can be significantly reduced. The present invention also provides a method of fabricating BJTs on selected areas of a very thin BOX using a conventional SOI starting wafer with a thick BOX. The reduced BOX thickness underneath the bipolar devices allows for a significantly reduced substrate bias compatible with the CMOS to be applied while maintaining the advantages of a thick BOX underneath the CMOS.Type: ApplicationFiled: February 17, 2010Publication date: August 19, 2010Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Herbert L. Ho, Mahender Kumar, Qiqing Ouyang, Paul A. Papworth, Christopher D. Sheraw, Michael D. Steigerwalt
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Patent number: 7776706Abstract: A method of forming a trench memory cell includes forming a trench capacitor within a substrate material, the trench capacitor including a node dielectric layer formed within a trench and a conductive capacitor electrode material formed within the trench in contact with the node dielectric layer; forming a strap mask so as cover one side of the trench and removing one or more materials from an uncovered opposite side of the trench; and forming a conductive buried strap material within the trench; wherein the strap mask is patterned in a manner such that a single-sided buried strap is defined within the trench, the single-sided buried strap configured in a manner such that the deep trench capacitor is electrically accessible at only one side of the trench.Type: GrantFiled: July 9, 2008Date of Patent: August 17, 2010Assignee: International Business Machines CorporationInventors: Kangguo Cheng, Ramachandra Divakaruni, Herbert L. Ho, Geng Wang
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Patent number: 7763518Abstract: The present invention provides a “collector-less” silicon-on-insulator (SOI) bipolar junction transistor (BJT) that has no impurity-doped collector. Instead, the inventive vertical SOI BJT uses a back gate-induced, minority carrier inversion layer as the intrinsic collector when it operates. In accordance with the present invention, the SOI substrate is biased such that an inversion layer is formed at the bottom of the base region serving as the collector. The advantage of such a device is its CMOS-like process. Therefore, the integration scheme can be simplified and the manufacturing cost can be significantly reduced. The present invention also provides a method of fabricating BJTs on selected areas of a very thin BOX using a conventional SOI starting wafer with a thick BOX. The reduced BOX thickness underneath the bipolar devices allows for a significantly reduced substrate bias compatible with the CMOS to be applied while maintaining the advantages of a thick BOX underneath the CMOS.Type: GrantFiled: April 8, 2008Date of Patent: July 27, 2010Assignee: International Business Machines CorporationInventors: Herbert L. Ho, Mahender Kumar, Qiqing Ouyang, Paul A. Papworth, Christopher D. Sheraw, Michael D. Steigerwalt
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Patent number: 7750388Abstract: The present invention relates to a semiconductor device that contains a trench metal-insulator-metal (MIM) capacitor and a field effect transistor (FET), and a design structure including the semiconductor device embodied in a machine readable medium. The trench MIM capacitor comprises a first metallic electrode layer located over interior walls of a trench in a substrate, a dielectric layer located in the trench over the first metallic electrode layer, and a second metallic electrode layer located in the trench over the dielectric layer. The FET comprises a source region, a drain region, a channel region between the source and drain regions, and a gate electrode over the channel region. The trench MIM capacitor is connected to the FET by a metallic strap.Type: GrantFiled: December 20, 2007Date of Patent: July 6, 2010Assignee: International Business Machines CorporationInventors: Herbert L. Ho, Subramanian S. Iyer, Vidhya Ramachandran
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Patent number: 7705386Abstract: A memory cell has an access transistor and a capacitor with an electrode disposed within a deep trench. STI oxide covers at least a portion of the electrode, and a liner covers a remaining portion of the electrode. The liner may be a layer of nitride over a layer of oxide. Some of the STI may cover a portion of the liner. In a memory array a pass wordline may be isolated from the electrode by the STI oxide and the liner.Type: GrantFiled: January 7, 2008Date of Patent: April 27, 2010Assignee: International Business Machines CorporationInventors: Kangguo Cheng, Johnathan E. Faltermeier, Herbert L. Ho, Paul C. Parries
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Patent number: 7691716Abstract: The present invention provides a “subcollector-less” silicon-on-insulator (SOI) bipolar junction transistor (BJT) that has no impurity-doped subcollector. Instead, the inventive vertical SOI BJT uses a back gate-induced, majority carrier accumulation layer as the subcollector when it operates. The SOI substrate is biased such that the accumulation layer is formed at the bottom of the first semiconductor layer. The advantage of such a device is its CMOS-like process. Therefore, the integration scheme can be simplified and the manufacturing cost can be significantly reduced. The present invention also provides a method of fabricating BJTs on selected areas of a very thin BOX using a conventional SOI starting wafer with a thick BOX. The reduced BOX thickness underneath the bipolar devices allows for a significantly reduced substrate bias compatible with the CMOS to be applied while maintaining the advantages of a thick BOX underneath the CMOS. A back-gated CMOS device is also provided.Type: GrantFiled: June 24, 2008Date of Patent: April 6, 2010Assignee: International Business Machines CorporationInventors: Herbert L. Ho, Mahender Kumar, Qiging Ouyang, Paul A. Papworth, Christopher D. Sheraw, Michael D. Steigerwalt
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Publication number: 20100038725Abstract: Ion implantation to change an effective work function for dual work function metal gate integration is presented. One method may include forming a high dielectric constant (high-k) layer over a first-type field effect transistor (FET) region and a second-type FET region; forming a metal layer having a first effective work function compatible for a first-type FET over the first-type FET region and the second-type FET region; and changing the first effective work function to a second, different effective work function over the second-type FET region by implanting a species into the metal layer over the second-type FET region.Type: ApplicationFiled: August 12, 2008Publication date: February 18, 2010Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Michael P. Chudzik, Martin M. Frank, Herbert L. Ho, Mark J. Hurley, Rashmi Jha, Naim Moumen, Vijay Narayanan, Dae-Gyu Park, Vamsi K. Paruchuri
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Publication number: 20090315124Abstract: Embedded DRAM MOSFETs including an array NFET having a gate stack comprising a high-K dielectric layer upon which is deposited a first metal oxide layer (CD1) then a conductive layer (TiN), and then a polysilicon layer (Poly). A logic PFET having substantially the same gate stack as the array NFET, and a logic NFET having a third gate stack comprising the high-K dielectric layer upon which is deposited the conductive layer (TiN) and then the polysilicon layer (Poly), without the first metal oxide layer (CD1) between the high-K dielectric layer and the conductive layer (TiN). The array NFET may therefore have a higher gate stack work function than the logic NFET, but substantially the same gate stack work function as the logic PFET.Type: ApplicationFiled: June 18, 2008Publication date: December 24, 2009Applicant: International Business Machines CorporationInventors: Xiangdong Chen, Herbert L. Ho, Geng Wang
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Publication number: 20090289291Abstract: A bottle shaped trench for an SOI capacitor is formed by a simple processing sequence. A non-conformal dielectric layer with an optional conformal dielectric diffusion barrier layer underneath is formed on sidewalls of a deep trench. Employing an isotropic etch, the non-conformal dielectric layer is removed from a bottom portion of the deep trench, leaving a dielectric spacer covering sidewalls of the buried insulator layer and the top semiconductor layer. The bottom portion of the deep trench is expanded to form a bottle shaped trench, and a buried plated is formed underneath the buried insulator layer. The dielectric spacer may be recessed during formation of a buried strap to form a graded thickness dielectric collar around the upper portion of an inner electrode. Alternately, the dielectric spacer may be removed prior to formation of a buried strap.Type: ApplicationFiled: May 21, 2008Publication date: November 26, 2009Applicant: International Business Machines CorporationInventors: Kangguo Cheng, Herbert L. Ho, Paul C. Parries, Geng Wang
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Publication number: 20090230508Abstract: An SOI layer has an initial trench extending therethrough, prior to deep trench etch. An oxidation step, such as thermal oxidation is performed to form a band of oxide on an inner periphery of the SOI layer to protect it during a subsequent RIE step for forming a deep trench. The initial trench may stop on BOX underlying the SOI. The band of oxide may also protect the SOI during buried plate implant or gas phase doping.Type: ApplicationFiled: March 14, 2008Publication date: September 17, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Thomas W. Dyer, Herbert L. Ho, Ravi M. Todi
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Publication number: 20090224308Abstract: A semiconductor memory device in which a vertical trench semiconductor-oxide-nitride-oxide-semiconductor (SONOS) memory cell is created in a semiconductor-on-insulator (SOI) substrate is provided that allows for the integration of dense non-volatile random access memory (NVRAM) cells in SOI-based complementary metal oxide semiconductor (CMOS) technology. The trench is processed using conventional trench processing and it is processed near the beginning of the inventive method that allows for the fabrication of the memory cell to be fully separated from SOI logic processing.Type: ApplicationFiled: March 25, 2009Publication date: September 10, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: David M. Dobuzinsky, Herbert L. Ho, Jack A. Mandelman, Yoichi Otani
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Patent number: 7575970Abstract: Methods of forming a deep trench capacitor through an SOI substrate, and a capacitor are disclosed. In one embodiment, a method includes forming a trench opening into the SOI substrate to the silicon substrate; depositing a sidewall spacer in the trench opening; etching to form the deep trench into the silicon substrate; forming a first electrode by implanting a dopant into the silicon substrate, whereby the sidewall spacer protects the BOX layer and the silicon layer; removing the sidewall spacer; depositing a node dielectric within the deep trench; and forming a second electrode by depositing a conductor in the deep trench. Implanting creates a substantially uniform depth doped region except at a portion adjacent to a lowermost portion of the deep trench, which may be substantially bulbous. The BOX layer is protected from undercutting by the sidewall spacer, and the implantation removes the need for out-diffusing dopant from silica glass.Type: GrantFiled: September 7, 2006Date of Patent: August 18, 2009Assignee: International Business Machines CorporationInventors: Herbert L. Ho, Kangguo Cheng, Yoichi Otani, Kevin R. Winstel
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Publication number: 20090184356Abstract: A deep trench is formed to a depth midway into a buried insulator layer of a semiconductor-on-insulator (SOI) substrate. A top semiconductor layer is laterally recessed by an isotropic etch that is selective to the buried insulator layer. The deep trench is then etched below a bottom surface of the buried insulator layer. Ion implantation is performed at an angle into the deep trench to dope the sidewalls of the deep trench beneath the buried insulator layer, while the laterally recessed sidewalls of the top semiconductor layer are not implanted with dopant ions. A node dielectric and trench fill materials are deposited into the deep trench. A buried strap has an upper buried strap sidewall that is offset from a lower buried strap sidewall and a deep trench sidewall.Type: ApplicationFiled: January 18, 2008Publication date: July 23, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: MaryJane Brodsky, Kangguo Cheng, Herbert L. Ho, Paul C. Parries, Kevin R. Winstel
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Publication number: 20090173980Abstract: A memory cell has an access transistor and a capacitor with an electrode disposed within a deep trench. STI oxide covers at least a portion of the electrode, and a liner covers a remaining portion of the electrode. The liner may be a layer of nitride over a layer of oxide. Some of the STI may cover a portion of the liner. In a memory array a pass wordline may be isolated from the electrode by the STI oxide and the liner.Type: ApplicationFiled: January 7, 2008Publication date: July 9, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Kangguo Cheng, Johnathan E. Faltermeier, Herbert L. Ho, Paul C. Parries
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Publication number: 20090159948Abstract: The present invention relates to a semiconductor device that contains a trench metal-insulator-metal (MIM) capacitor and a field effect transistor (FET), and a design structure including the semiconductor device embodied in a machine readable medium. The trench MIM capacitor comprises a first metallic electrode layer located over interior walls of a trench in a substrate, a dielectric layer located in the trench over the first metallic electrode layer, and a second metallic electrode layer located in the trench over the dielectric layer. The FET comprises a source region, a drain region, a channel region between the source and drain regions, and a gate electrode over the channel region. The trench MIM capacitor is connected to the FET by a metallic strap.Type: ApplicationFiled: December 20, 2007Publication date: June 25, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Herbert L. Ho, Subramanian S. Iyer, Vidhya Ramachandran
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Patent number: 7550359Abstract: A method for fabricating silicon-on-insulator (SOI) trench memory includes forming a trench on a substrate, wherein a buried oxide layer is disposed on the substrate, a SOI layer is disposed on the buried oxide layer, and a hardmask layer is disposed on the SOI layer, implanting ions into the substrate and the SOI layer on a first opposing side of the trench and a second opposing side the trench to partially form a capacitor, depositing a node dielectric in the trench, filling the trench with a first polysilicon, removing a portion of the first polysilicon from the trench, removing an exposed portion of the node dielectric, filling the trench with a second polysilicon, masking to define an active region on the hardmask layer, forming shallow trench isolation (STI) such that the STI contacts a portion of the buried oxide layer, removing the hardmask layer, and forming a transistor.Type: GrantFiled: May 7, 2008Date of Patent: June 23, 2009Assignee: International Business Machines CorporationInventors: Kangguo Cheng, Herbert L. Ho, Geng Wang
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Publication number: 20090158234Abstract: A semiconductor memory device and a design structure including the semiconductor memory device embodied in a machine readable medium is provided. In particular the present invention includes a semiconductor memory device in which a vertical trench semiconductor-oxide-nitride-oxide-semiconductor (SONOS) memory cell is created in a semiconductor-on-insulator (SOI) substrate is provided that allows for the integration of dense non-volatile random access memory (NVRAM) cells in SOI-based complementary metal oxide semiconductor (CMOS) technology. The trench is processed using conventional trench processing and it is processed near the beginning of the inventive method that allows for the fabrication of the memory cell to be fully separated from SOI logic processing.Type: ApplicationFiled: December 13, 2007Publication date: June 18, 2009Applicant: INTERNATIONAL MACHINES BUSINESS CORPORATIONInventors: David M. Dobuzinsky, Herbert L. Ho, Jack A. Mandelman, Yoichi Otani