Patents by Inventor Krishna Saraswat

Krishna Saraswat 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: 20110266550
    Abstract: This invention provides a method of forming semiconductor films on dielectrics at temperatures below 400° C. Semiconductor films are required for thin film transistors (TFTs), on-chip sensors, on-chip micro-electromechanical systems (MEMS) and monolithic 3D-integrated circuits. For these applications, it is advantageous to form the semiconductor films below 400° C. because higher temperatures are likely to destroy any underlying devices and/or substrates. This invention successfully achieves low temperature growth of germanium films using diboran. First, diboran gas is supplied into a reaction chamber at a temperature below 400° C. The diboran decomposes itself at the given temperature and decomposed boron is attached to the surface of a dielectric, for e.g., SiO2, forming a nucleation site and/or a seed layer. Second, source gases for semiconductor film formation, for e.g., SiH4, GeH4, etc., are supplied into the chamber, thereby forming a semiconductor film.
    Type: Application
    Filed: May 17, 2011
    Publication date: November 3, 2011
    Applicants: STANFORD UNIVERSITY, NEC CORPORATION
    Inventors: Munehiro TADA, Krishna SARASWAT
  • Patent number: 7968434
    Abstract: This invention provides a method of forming semiconductor films on dielectrics at temperatures below 400° C. Semiconductor films are required for thin film transistors (TFTs), on-chip sensors, on-chip micro-electromechanical systems (MEMS) and monolithic 3D-integrated circuits. For these applications, it is advantageous to form the semiconductor films below 400° C. because higher temperatures are likely to destroy any underlying devices and/or substrates. This invention successfully achieves low temperature growth of germanium films using diboran. First, diboran gas is supplied into a reaction chamber at a temperature below 400° C. The diboran decomposes itself at the given temperature and decomposed boron is attached to the surface of a dielectric, for e.g., SiO2, forming a nucleation site and/or a seed layer. Second, source gases for semiconductor film formation, for e.g., SiH4, GeH4, etc., are supplied into the chamber, thereby forming a semiconductor film.
    Type: Grant
    Filed: November 14, 2008
    Date of Patent: June 28, 2011
    Assignees: NEC Corporation, Stanford University
    Inventors: Munehiro Tada, Krishna Saraswat
  • Publication number: 20100123218
    Abstract: This invention provides a method of forming semiconductor films on dielectrics at temperatures below 400° C. Semiconductor films are required for thin film transistors (TFTs), on-chip sensors, on-chip micro-electromechanical systems (MEMS) and monolithic 3D-integrated circuits. For these applications, it is advantageous to form the semiconductor films below 400° C. because higher temperatures are likely to destroy any underlying devices and/or substrates. This invention successfully achieves low temperature growth of germanium films using diboran. First, diboran gas is supplied into a reaction chamber at a temperature below 400° C. The diboran decomposes itself at the given temperature and decomposed boron is attached to the surface of a dielectric, for e.g., SiO2, forming a nucleation site and/or a seed layer. Second, source gases for semiconductor film formation, for e.g., SiH4, GeH4, etc., are supplied into the chamber, thereby forming a semiconductor film.
    Type: Application
    Filed: November 14, 2008
    Publication date: May 20, 2010
    Applicant: NEC CORPORATION
    Inventors: Munehiro TADA, Krishna SARASWAT
  • Publication number: 20070170541
    Abstract: Excellent capacitor-voltage characteristics with near-ideal hysteresis are realized in a capacitive-like structure that uses an electrode substrate-type material with a high-k dielectric layer having a thickness of a few-to-several Angstroms capacitance-based SiO2 equivalent (“TOx,Eq”). According to one particular example embodiment, a semiconductor device structure has an electrode substrate-type material having a Germanium-rich surface material. The electrode substrate-type material is processed to provide this particular electrode surface material in a form that is thermodynamically stable with a high-k dielectric material. A dielectric layer is then formed over the electrode surface material with the high-k dielectric material at a surface that faces, lies against and is thermodynamically stable with the electrode surface material.
    Type: Application
    Filed: March 31, 2003
    Publication date: July 26, 2007
    Inventors: Chi Chui, Krishna Saraswat, Baylor Triplett, Paul McIntyre
  • Publication number: 20060019466
    Abstract: Germanium circuit-type structures are facilitated. In one example embodiment, a multi-step growth and anneal process is implemented to grow Germanium (Ge) containing material, such as heteroepitaxial-Germanium, on a substrate including Silicon (Si) or Silicon-containing material. In certain applications, defects are generally confined near a Silicon/Germanium interface, with defect threading to an upper surface of the Germanium containing material generally being inhibited. These approaches are applicable to a variety of devices including Germanium MOS capacitors, pMOSFETs and optoelectronic devices.
    Type: Application
    Filed: July 22, 2005
    Publication date: January 26, 2006
    Inventors: Ammar Nayfeh, Chi On Chui, Krishna Saraswat, Takao Yonehara
  • Patent number: 5271274
    Abstract: A system and method is disclosed for measuring thickness of at least one film on a substrate by propagating an acoustic wave through the film on a substrate such that echo waves are generated and received by a transducer. An output signal is generated and processed to give a thickness value. The thickness valve is obtained from the time lapse between the propagated wave and receipt of the echo wave; by the frequency domain of the echo wave; or the phase of the echo wave.
    Type: Grant
    Filed: August 14, 1991
    Date of Patent: December 21, 1993
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: B. T. Khuri-Yakub, Sanjay Bhardwaj, Krishna Saraswat
  • Patent number: 4715937
    Abstract: A process utilizing a microwave discharge technique for performing direct nitridation of silicon at a relatively low growth temperature of no more than about 500.degree. C. in a nitrogen plasma ambient without the presence of hydrogen or a fluorine-containing species. Nitrogen is introduced through a quartz tube. A silicon rod connected to a voltage source is placed in the quartz tube and functions as an anodization electrode. The silicon wafer to be treated is connected to a second voltage source and functions as the second electrode of the anodizing circuit. A small DC voltage is applied to the silicon wafer to make the plasma current at the wafer and the silicon rod equal and minimize contamination of the film.
    Type: Grant
    Filed: May 5, 1986
    Date of Patent: December 29, 1987
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Mehrdad M. Moslehi, Chi Y. Fu, Krishna Saraswat