Patents by Inventor Yaocheng Liu

Yaocheng Liu 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: 20090166770
    Abstract: A method of fabricating a gate electrode for a gate of a metal oxide semiconductor field effect transistor (MOSFET), where the transistor has a structure incorporating a gate disposed on a substrate. The substrate comprises a source-drain region. The gate includes a gate electrode disposed on a gate dielectric and surrounded by a spacer. The gate electrode includes a capping layer of polysilicon (poly-Si) and a thin polycrystalline intermixed silicon-germanium (SiGe) layer superposed on the gate dielectric. The thin polycrystalline intermixed silicon-germanium (SiGe) layer may be formed by a high-temperature ultrafast melt-crystalization annealing process. The melt-crystallization process of the intermixed silicon-germanium provides an active dopant concentration that reduces the width of a depletion region formed at an interface of the polycrystalline intermixed silicon-germanium (SiGe) layer and the gate dielectric.
    Type: Application
    Filed: January 2, 2008
    Publication date: July 2, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Oleg Gluschenkov, Sameer H. Jain, Yaocheng Liu
  • Patent number: 7524740
    Abstract: A method of forming a localized region of relaxed Si in a layer of strained Si arranged within a strained silicon directly on insulator (SSDOI) semiconductor substrate is provided by the invention. The strained Si layer is formed on a buried oxide (BOX) layer disposed on a Si substrate base. The method includes depositing a nitride hard mask pattern above a region of the strained Si layer in which enhanced electron mobility is desired, leaving an unmasked region within the strained Si layer, and carrying out various other processing steps to modify and relax the unmasked portion of the strained region. The method includes growing an EPI SiGe region upon the unmasked region using pre-amorphization implantation, and forming a buried amorphous SiGe region in a portion of the EPI SiGe region, and an amorphous Si region, below the amorphous SiGe region. Then, using SPE regrowth, modifying the amorphous SiGe and amorphous Si regions to realize an SPE SiGe region and relaxed SPE Si layer.
    Type: Grant
    Filed: April 24, 2008
    Date of Patent: April 28, 2009
    Assignee: International Business Machines Corporation
    Inventors: Yaocheng Liu, Devendra Kumar Sadana, Kern Rim
  • Publication number: 20090081836
    Abstract: A method of forming crystalline Si:C in source and drain regions is provided. After formation of shallow trench isolation and gate electrodes of field effect transistors, gate spacers are formed on gate electrodes. Preamorphization implantation is performed in the source and drain regions, followed by carbon implantation. The upper portion of the source and drain regions comprises an amorphous mixture of silicon, germanium, and/or carbon. An anti-reflective layer is deposited to enhance the absorption of a laser beam into the silicon substrate. The laser beam is scanned over the silicon substrate including the upper source and drain region with the amorphous mixture. The energy of the laser beam is controlled so that the temperature of the semiconductor substrate is above the melting temperature of the amorphous mixture but below the glass transition temperature of silicon oxide so that structural integrity of the semiconductor structure is preserved.
    Type: Application
    Filed: September 24, 2007
    Publication date: March 26, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Yaocheng Liu, Qiqing C. Ouyang, Kathryn T. Schonenberg, Chun-Yung Sung
  • Patent number: 7504309
    Abstract: A method forms a gate conductor over a substrate, and simultaneously forms spacers on sides of the gate conductor and a gate cap on the top of the gate conductor. Isolation regions are formed in the substrate and the method implants an impurity into exposed regions of the substrate not protected by the gate conductor and the spacers to form source and drain regions. The method deposits a mask over the gate conductor, the spacers, and the source and drain regions. The mask is recessed to a level below a top of the gate conductor but above the source and drain regions, such that the spacers are exposed and the source and drain regions are protected by the mask. With the mask in place, the method then safely removes the spacers and the gate cap, without damaging the source/drain regions or the isolation regions (which are protected by the mask). Next, the method removes the mask and then forms silicide regions on the gate conductor and the source and drain regions.
    Type: Grant
    Filed: October 12, 2006
    Date of Patent: March 17, 2009
    Assignee: International Business Machines Corporation
    Inventors: Thomas W. Dyer, Sunfei Fang, Jiang Yan, Jun Jung Kim, Yaocheng Liu, Huilong Zhu
  • Patent number: 7498243
    Abstract: Single-crystalline growth is realized using a liquid-phase crystallization approach involving the inhibition of defects typically associated with liquid-phase crystalline growth of lattice mismatched materials. According to one example embodiment, a semiconductor device structure includes a substantially single-crystal region. A liquid-phase material is crystallized to form the single-crystal region using an approach involving defect inhibition for the promotion of single-crystalline growth. In some instances, this defect inhibition involves the reduction and/or elimination of defects using a relatively small physical opening via which a crystalline growth front propagates. In other instances, this defect inhibition involves causing a change in crystallization front direction relative to a crystallization seed location.
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: March 3, 2009
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Yaocheng Liu, Michael D. Deal, James D. Plummer
  • Publication number: 20090050942
    Abstract: The embodiments of the invention comprise a self-aligned super stressed p-type field effect transistor (PFET). More specifically, a field effect transistor comprises a channel region comprising N-doped material and a gate above the channel region. The field effect transistor also includes a source region on a first side of the channel region and a drain region on a second side of the channel region opposite the first side. The source and drain regions each comprise silicon germanium, wherein the silicon germanium has structural indicia of epitaxial growth.
    Type: Application
    Filed: August 21, 2007
    Publication date: February 26, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Yaocheng Liu, Zhijiong Luo, Huilong Zhu
  • Publication number: 20090032840
    Abstract: A semiconductor device and method of manufacture and, more particularly, a semiconductor device having strain films and a method of manufacture. The device includes an embedded SiGeC layer in source and drain regions of an NFET device and an embedded SiGe layer in source and drain regions of a PFET device. The PFET device is subject to compressive strain. The method includes embedding SiGe in source and drain regions of an NFET device and implanting carbon in the embedded SiGe forming an SiGeC layer in the source and drain regions of the NFET device. The SiGeC is melt laser annealed to uniformly distribute the carbon in the SiGeC layer, thereby counteracting a strain generated by the embedded SiGe.
    Type: Application
    Filed: July 31, 2007
    Publication date: February 5, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: OLEG GLUSCHENKOV, SAMEER JAIN, YAOCHENG LIU
  • Patent number: 7485519
    Abstract: A field effect transistor (“FET”) is formed to include a stress in a channel region of an active semiconductor region of an SOI substrate. A gate is formed to overlie the active semiconductor region, after which a sacrificial stressed layer is formed which overlies the gate and the active semiconductor region. Then, the SOI substrate is heated to cause a flowable dielectric material in a buried dielectric layer of the SOI substrate to soften and reflow. As a result of the reflowing, the sacrificial stressed layer induces stress in a channel region of the active semiconductor region underlying the gate. A source region and a drain region are formed in the active semiconductor region, desirably after removing the sacrificial stressed layer.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: February 3, 2009
    Assignee: International Business Machines Corporation
    Inventors: Dureseti Chidambarrao, William K. Henson, Yaocheng Liu
  • Patent number: 7473594
    Abstract: An embedded silicon carbon (Si:C) having a substitutional carbon content in excess of one percent in order to effectively increase electron mobility by application of tension to a channel region of an NFET is achieved by overfilling a gap or trench formed by transistor gate structures with Si:C and polishing an etching the Si:C to or below a surface of a raised gate structure in a super-Damascene process, leaving Si:C only in selected regions above the transistor source and drain, even though processes capable of depositing Si:C with sufficiently high substitutional carbon content are inherently non-selective.
    Type: Grant
    Filed: July 25, 2006
    Date of Patent: January 6, 2009
    Assignee: International Business Machines Corporation
    Inventors: Ashima B. Chakravarti, Dureseti Chidambarrao, Judson R. Holt, Yaocheng Liu, Kern Rim
  • Patent number: 7473608
    Abstract: The present invention relates to a semiconductor device comprising at least one n-channel field effect transistor (n-FET). Specifically, the n-FET comprises first and second patterned stressor layers that both contain a carbon-substituted and tensilely stressed single crystal semiconductor. The first patterned stressor layer has a first carbon concentration and is located in source and drain (S/D) extension regions of the n-FET at a first depth. The second patterned stressor layer has a second, higher carbon concentration and is located in S/D regions of the n-FET at a second, deeper depth. Such an n-FET with the first and second patterned stressor layers of different carbon concentration and different depths provide improved stress profile for enhancing electron mobility in the channel region of the n-FET.
    Type: Grant
    Filed: August 17, 2007
    Date of Patent: January 6, 2009
    Assignee: International Business Machines Corporation
    Inventors: Jinghong H. Li, Yaocheng Liu, Zhijiong Luo, Anita Madan, Nivo Rovedo
  • Patent number: 7473626
    Abstract: A method to control the poly-Si depletion effect in CMOS structures utilizing a gas phase doping process which is capable of providing a high concentration of dopant atoms at the gate dielectric/poly-Si interface is provided. The present invention also provides CMOS structure including, for example, nFETs and/or pFETs, that are fabricated utilizing the gas phase doping technique described herein.
    Type: Grant
    Filed: April 11, 2006
    Date of Patent: January 6, 2009
    Assignee: International Business Machines Corporation
    Inventors: Yaocheng Liu, Alexander Reznicek, Devendra K. Sadana
  • Publication number: 20080258234
    Abstract: A semiconductor structure provides lower parasitic capacitance between the gate electrode and contact vias while providing substantially the same level of stress applied by a nitride liner as conventional MOSFETs by reducing the height of the gate electrode and maintaining substantially the same height for the gate spacer. The nitride liner contacts only the outer sidewalls of the gate spacer, while not contacting inner sidewalls, or only a small area of the inner sidewalls of the gate spacer, therefore applying substantially the same level of stress to the channel of the MOSFET as conventional MOSFETs. The volume surrounded by the gate spacer and located above the gate electrode is either filled with a low-k dielectric material or occupied by a cavity having a dielectric constant of substantially 1.0. The reduced height of the gate electrode and the low-k dielectric gate filler or the cavity reduces the parasitic capacitance.
    Type: Application
    Filed: April 23, 2007
    Publication date: October 23, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: William K. Henson, Paul Chung-Muh Chang, Dureseti Chidambarrao, Ricardo A. Donaton, Yaocheng Liu, Shreesh Narasimha, Amanda L. Tessier
  • Publication number: 20080248626
    Abstract: A hybrid orientation direct-semiconductor-bond (DSB) substrate with shallow trench isolation (STI) that is self-aligned to recrystallization boundaries is formed by patterning a hard mask layer for STI, a first amorphization implantation into openings in the hard mask layer, lithographic patterning of portions of a top semiconductor layer, a second amorphization implantation into exposed portions of the DSB substrate, recrystallization of the portions of the top semiconductor layer, and formation of STI utilizing the pattern in the hard mask layer. The edges of patterned photoresist for the second amorphization implantation are located within the openings in the patterned hard mask layer. Defective boundary regions formed underneath the openings in the hard mask layer are removed during the formation of STI to provide a leakage path free substrate. Due to elimination of a requirement for increased STI width, device density is increased compared to non-self-aligning process integration schemes.
    Type: Application
    Filed: April 5, 2007
    Publication date: October 9, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Yaocheng Liu, Zhijiong Luo, Katherine L. Saenger, Chun-Yung Sung, Rajasekhar Venigalla, Haizhou Yin
  • Publication number: 20080246041
    Abstract: A method of fabricating a silicon-on-insulator (SOI) N-channel metal oxide semiconductor field effect transistor (nMOSFET), where the transistor has a structure incorporating a gate disposed above a body of the SOI substrate. The body comprises of a first surface and a second surface. The second surface interfaces between the body and the insulator of the SOI. Between the first surface and second surface is defined a channel region separating a source region and a drain region. Each of the source region and drain region includes a third surface under which is embedded crystalline silicon-carbon (Si:C), which extends from the second surface to the third surface.
    Type: Application
    Filed: April 5, 2007
    Publication date: October 9, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Yaocheng Liu, Huilong Zhu
  • Publication number: 20080237709
    Abstract: A field effect transistor (“FET”) is formed to include a stress in a channel region of an active semiconductor region of an SOI substrate. A gate is formed to overlie the active semiconductor region, after which a sacrificial stressed layer is formed which overlies the gate and the active semiconductor region. Then, the SOI substrate is heated to cause a flowable dielectric material in a buried dielectric layer of the SOI substrate to soften and reflow. As a result of the reflowing, the sacrificial stressed layer induces stress in a channel region of the active semiconductor region underlying the gate. A source region and a drain region are formed in the active semiconductor region, desirably after removing the sacrificial stressed layer.
    Type: Application
    Filed: March 30, 2007
    Publication date: October 2, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Dureseti Chidambarrao, William K. Henson, Yaocheng Liu
  • Publication number: 20080224218
    Abstract: A CMOS structure includes an n-FET device comprising an n-FET channel region and a p-FET device comprising a p-FET channel region. The n-FET channel region includes a first silicon material layer located upon a silicon-germanium alloy material layer. The p-FET channel includes a second silicon material layer located upon a silicon-germanium-carbon alloy material layer. The silicon-germanium alloy material layer induces a desirable tensile strain within the n-FET channel. The silicon-germanium-carbon alloy material layer suppresses an undesirable tensile strain within the p-FET channel region. A silicon-germanium-carbon alloy material from which is comprised the silicon-germanium-carbon alloy material layer may be formed by selectively incorporating carbon into a silicon-germanium alloy material from which is formed the silicon-germanium alloy material layer.
    Type: Application
    Filed: March 13, 2007
    Publication date: September 18, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Yaocheng Liu, Ricardo A. Donaton, Kern Rim
  • Publication number: 20080217697
    Abstract: A method to control the poly-Si depletion effect in CMOS structures utilizing a gas phase doping process which is capable of providing a high concentration of dopant atoms at the gate dielectric/poly-Si interface is provided. The present invention also provides CMOS structure including, for example, nFETs and/or pFETs, that are fabricated utilizing the gas phase doping technique described herein.
    Type: Application
    Filed: May 27, 2008
    Publication date: September 11, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Yaocheng Liu, Alexander Reznicek, Devendra K. Sadana
  • Publication number: 20080206965
    Abstract: Disclosed herein is a method of preparing strained silicon comprising annealing a carbon-doped silicon-germanium (SiGe:C) alloy containing region disposed adjacent to a silicon region, wherein the lattice constant of the SiGe:C alloy after annealing is greater than that of the SiGe:C alloy prior to annealing. The method can be used to prepare articles including metal oxide semiconductor field effect transistor (MOSFET) devices.
    Type: Application
    Filed: February 27, 2007
    Publication date: August 28, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Oleg Gluschenkov, Yaocheng Liu, Alexander Reznicek, Devendra Sadana
  • Publication number: 20080191243
    Abstract: Disclosed are embodiments of an n-FET structure with silicon carbon S/D regions completely contained inside amorphization regions and with a carbon-free gate electrode. Containing carbon within the amorphization regions, ensures that all of the carbon is substitutional following re-crystallization to maximize the tensile stress imparted on channel region. The gate stack is capped during carbon implantation so the risk of carbon entering the gate stack and degrading the conductivity of the gate polysilicon and/or damaging the gate oxide is essentially eliminated. Thus, the carbon implant regions can be formed deeper. Deeper S/D carbon implants which are completely amorphized and then re-crystallized provide greater tensile stress on the n-FET channel region to further optimize electron mobility. Additionally, the gate electrode is uncapped during the n-type dopant process, so the n-type dopant dose in the gate electrode can be at least great as the dose in the S/D regions.
    Type: Application
    Filed: February 8, 2007
    Publication date: August 14, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Yaocheng Liu, Shreesh Narasimha, Katsunori Onishi, Kern Rim
  • Publication number: 20080191281
    Abstract: A method is provided for fabricating a field effect transistor (“FET”) having a channel region in a semiconductor-on-insulator (“SOI”) layer of an SOI substrate. Desirably, in such method, a sacrificial stressed layer is formed to overlie a first portion of an active semiconductor region but not overlie second portion of the active semiconductor region which shares a common boundary with the first portion. After forming trenches in the SOI layer, the SOI substrate is heated with the stressed layer thereon sufficiently to cause the stressed layer to relax, thereby causing the stressed layer to apply a first stress to the first portion and to apply a second stress to the second portion. For example, when the first stress is tensile, the second stress is compressive, or the first stress can be compressive when the second stress is tensile. Desirably, the stressed layer is then removed to expose the first and second portions of the active semiconductor region.
    Type: Application
    Filed: February 12, 2007
    Publication date: August 14, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Dureseti Chidambarrao, William K. Henson, Yaocheng Liu