Patents by Inventor L. Rafael Reif

L. Rafael Reif 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).

  • Patent number: 5028977
    Abstract: A vertical bipolar transistor is formed along with an IGFET transistor in a process in which the bipolar transistor collector, base and emitter structure is formed in the body of a semiconductor mesa-like structure while the IGFET transistor is formed in and along one of the sidewalls of the structure. Source and drain regions are formed in the structure by ion-implantation using a polysilicon gate electrode formed over a gate insulator on the sidewall as a self-aligning mask.
    Type: Grant
    Filed: June 16, 1989
    Date of Patent: July 2, 1991
    Assignee: Massachusetts Institute of Technology
    Inventors: K. O. Kenneth, Hae-Seung Lee, L. Rafael Reif
  • Patent number: 4957777
    Abstract: The selective or blanket deposition of titanium silicide using a Very Low Pressure Chemical Vapor Deposition process is described. Silane and titanium tetrachloride are used as the silicon and titanium sources, respectively. A thin polysilicon layer is deposited prior to the silicide deposition to promote the nucleation of titanium silicide. It is shown that selective deposition is possible by controlling the polysilicon and the titanium silicide deposition times. The resulting titanium silicide films have resistivities in the range of 15-25 micro-ohms-cm.
    Type: Grant
    Filed: October 12, 1989
    Date of Patent: September 18, 1990
    Assignee: Massachusetts Institute of Technology
    Inventors: Vida Ilderem, L. Rafael Reif, Prabha K. Tedrow
  • Patent number: 4773355
    Abstract: A method and apparatus for forming epitaxial thin film layers on substrates having abrupt transitions between layers of different composition or layers of different or like composition with different degrees of doping included therein. Gaseous reactants containing the desired elements to be included in the first film layer are injected into a CVD reaction chamber containing a substrate. The substrate is heated to a temperature high enough to obtain an epitaxial deposit, but low enough so as not to cause decomposition of the reactants. Once the gaseous reactant flows reach steady-state, an electric discharge or plasma is created in the gases to initiate the decomposition reaction and obtain a deposit. In this way, no transient effects are present. Once the deposit has attained sufficient thickness, the electric discharge is turned off to abruptly terminate deposition.
    Type: Grant
    Filed: December 9, 1986
    Date of Patent: September 27, 1988
    Assignee: Massachusetts Institute of Technology
    Inventors: L. Rafael Reif, Clifton G. Fonstad, Jr.
  • Patent number: 4668530
    Abstract: This invention relates to a process and apparatus for the Low Pressure Chemical Vapor Deposition (LPCVD) of polycrystalline refractory metal silicides, such as TiSi.sub.2, in a reactor. An oxidized Si wafer is loaded in the reactor. The reactor is pumped down to a pressure of about 10.sup.-7 Torr, or less. The Si substrate is heated to the predetermined deposition temperature of about 630.degree. C. while avoiding heating of the reactor walls. The reactor is then purged with an inert gas, such as nitrogen. Next, polysilicon is deposited on the wafer by introducing SiH.sub.4 into the reactor at a pressure in the order of 0.2 Torr. A layer of polycrystalline titanium silicide is then formed on the polysilicon layer by introducing reactants, such as TiCl.sub.4 and SiH.sub.4, into the reactor at depositon temperatures between about 650.degree. to 700.degree. C. and pressures of between about 50 to 460 m Torr.
    Type: Grant
    Filed: July 23, 1985
    Date of Patent: May 26, 1987
    Assignee: Massachusetts Institute of Technology
    Inventors: L. Rafael Reif, Prabha K. Tedrow, Vida Ilderem
  • Patent number: 4659401
    Abstract: A method and apparatus for forming epitaxial thin film layers on substrates having abrupt transitions between layers of different composition or layers of different or like composition with different degrees of doping included therein. Gaseous reactants containing the desired elements to be included in the first film layer are injected into a CVD reaction chamber containing a substrate. The substrate is heated to a temperature high enough to obtain an epitaxial deposit, but low enough so as not to cause decomposition of the reactants. Once the gaseous reactant flows reach steady-state, an electric discharge or plasma is created in the gases to initiate the decomposition reaction and obtain a deposit. In this way, no transient effects are present. Once the deposit has attained sufficient thickness, the electric discharge is turned off to abruptly terminate deposition.
    Type: Grant
    Filed: June 10, 1985
    Date of Patent: April 21, 1987
    Assignee: Massachusetts Institute of Technology
    Inventors: L. Rafael Reif, Clifton G. Fonstad, Jr.
  • Patent number: 4579609
    Abstract: A method and apparatus for low temperature deposition of epitaxial films using low pressure chemical vapor deposition (CVD) with and without plasma enhancement. More specifically, the process enables CVD of epitaxial silicon at temperatures below 800.degree. C. by use of an in situ argon plasma sputter cleaning treatment of the silicon substrate prior to deposition.
    Type: Grant
    Filed: June 8, 1984
    Date of Patent: April 1, 1986
    Assignee: Massachusetts Institute of Technology
    Inventors: L. Rafael Reif, Thomas J. Donahue, Wayne R. Burger