Patents by Inventor Lester F. Eastman

Lester F. Eastman 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: 4728616
    Abstract: A heterojunction transistor doped to form a specially-shaped emitter-base conduction band step or spike is disclosed. The potential barrier is then utilized to accelerate electrons across the base region at the maximum velocity obtainable without scattering electrons to the upper valleys. In this manner the electrons may be transported across the base region virtually without collisions and at a velocity approximately 10 times that of normal electron diffusion across the base region, thus increasing the frequence response of the transistor.
    Type: Grant
    Filed: February 20, 1987
    Date of Patent: March 1, 1988
    Assignee: Cornell Research Foundation, Inc.
    Inventors: David G. Ankri, Lester F. Eastman, Walter H. Ku
  • Patent number: 4700353
    Abstract: Modulation of a semiconductor laser device is achieved at microwave frequencies by the application of transverse fields which produce energy shifts in the gain spectra of the laser device. The laser device is a PN diode which has a body portion constructed from a nonconductive material, with P and N type implants on opposite sides. The P and N implants define a transition region, or layer, on the order of 1 micron in width, in which is formed a quantum well having a thickness on the order of 50 to 100 Angstroms. Application of a bias voltage across the PN junction provides lasing of the device. An electrode on the surface of the transition layer allows application of a transverse electric field to the PN junction. This transverse field quenches the lasing of the device, to provide modulation of the laser.
    Type: Grant
    Filed: August 12, 1985
    Date of Patent: October 13, 1987
    Assignee: Cornell Research Foundation, Inc.
    Inventors: Edward Van Gieson, Gary W. Wicks, Eric Elias, Lester F. Eastman
  • Patent number: 4672404
    Abstract: A heterojunction transistor doped to form a specially-shaped emitter-base conduction band step or spike is disclosed. The potential barrier is then utilized to accelerate electrons across the base region at the maximum velocity obtainable without scattering electrons to the upper valleys. In this manner the electrons bay be transported across the base region virtually without collisions and at a velocity approximately 10 times that of normal electron diffusion across the base region, thus increasing the frequence response of the transistor.
    Type: Grant
    Filed: September 3, 1985
    Date of Patent: June 9, 1987
    Assignee: Cornell Research Foundation, Inc.
    Inventors: David G. Ankri, Lester F. Eastman, Walter H. Ku
  • Patent number: 4649405
    Abstract: A high frequency transferred electron device having electron ballistic injection and extraction for very high efficiency is disclosed. The device comprises a semiconductor body having at least two electrodes with a thin barrier layer being formed at one electrode for launching ballistic electrons at a controlled kinetic energy into the body. The body includes a drift region having a low, controlled density of electrons and impurities. A second heavily doped (N+) collector semiconductor layer at the second electrode insures that there is no barrier at the second electrode interface, thereby allowing energetic electrons to be removed from the drift region and allowing entry of new ballistic electrons to improve the efficiency and frequency response of the device.
    Type: Grant
    Filed: April 10, 1984
    Date of Patent: March 10, 1987
    Assignee: Cornell Research Foundation, Inc.
    Inventor: Lester F. Eastman
  • Patent number: 4564509
    Abstract: A method of removing oxygen and water vapor and other oxygen bearing gas species from reactant gases comprising the use of an appropriate solution containing an active gettering metal, selected from the group of aluminum, magnesium, calcium and lithium in liquid phase through a moderate temperature range, including room temperature and above as an oxygen gettering step, through the formation of an oxide of said metal wherein the said metal becomes continuously available for oxidation by exposing the said unreacted metal to the gas by bubbling the reactant gas through a ternary melt of gallium-indium and the said metal in a nonreactive container and maintaining in solid phase an excess of the active gettering method so that the capacity for removing the oxygen and water vapor and other oxygen bearing gas species may be extended by the active metal going into solution in the melt from the solid as the metal oxide is formed and goes out of solution.
    Type: Grant
    Filed: June 30, 1983
    Date of Patent: January 14, 1986
    Assignee: Northeast Semiconductor Inc.
    Inventors: James R. Shealy, Lester F. Eastman
  • Patent number: 4398963
    Abstract: Ultra low resistance heterojunction ohmic contacts to semiconductors such gallium arsenide (GaAs) is described wherein a single crystal layer of germanium degenerately doped with arsenic is deposited on gallium arsenide using molecular-beam epitaxy (MBE). A metallic film is then deposited over the single crystal layer of heavily doped germanium so as to obtain a non-alloyed heterojunction ohmic contact having a very low specific resistance.
    Type: Grant
    Filed: November 19, 1980
    Date of Patent: August 16, 1983
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Richard A. Stall, Colin E. C. Wood, Lester F. Eastman