Lester F Eastman

US Patent:

8450774, May 28, 2013

Filed:

Jul 12, 2010

Appl. No.:

13/378043

Inventors:

Junxia Shi - Ithaca NY, US
Lester Fuess Eastman - Ithaca NY, US

Assignee:

Cornell University - Ithaca NY

International Classification:

H01L 31/102
H01L 29/66
H01L 31/06
H01L 29/12
H01L 29/20

US Classification:

257189, 438785, 257 76, 257183, 257187, 257192, 257201, 257613, 257615

Abstract:

In one example, we describe a new high performance AlGaN/GaN metal-insulator-semiconductor heterostructure field-effect transistor (MISHFET), which was fabricated using HfO2 as the surface passivation and gate insulator. The gate and drain leakage currents are drastically reduced to tens of nA, before breakdown. Without field plates, for 10 μm of gate-drain spacing, the off-state breakdown voltage is 1035V with a specific on-resistance of 0. 9 mΩ-cm2. In addition, there is no current slump observed from the pulse measurements. This is the best performance reported on GaN-based, fast power-switching devices on sapphire, up to now, which efficiently combines excellent device forward, reverse, and switching characteristics. Other variations, features, and examples are also mentioned here.

US Patent:

46494057, Mar 10, 1987

Filed:

Apr 10, 1984

Appl. No.:

6/598755

Inventors:

Lester F. Eastman - Ithaca NY

Assignee:

Cornell Research Foundation, Inc. - Ithaca NY

International Classification:

H01L 2988
H01L 2920
H01L 2986

US Classification:

357 3

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.

US Patent:

47286164, Mar 1, 1988

Filed:

Feb 20, 1987

Appl. No.:

7/016893

Inventors:

David G. Ankri - Paris, FR
Lester F. Eastman - Ithaca NY
Walter H. Ku - Ithaca NY

Assignee:

Cornell Research Foundation, Inc. - Ithaca NY

International Classification:

H01L 2122
H01L 2126
H01L 29205

US Classification:

437 22

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.

US Patent:

46724044, Jun 9, 1987

Filed:

Sep 3, 1985

Appl. No.:

6/771169

Inventors:

David G. Ankri - Paris, FR
Lester F. Eastman - Ithaca NY
Walter H. Ku - Ithaca NY

Assignee:

Cornell Research Foundation, Inc. - Ithaca NY

International Classification:

H01L 2712
H01L 29161
H01L 2972

US Classification:

357 16

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.

US Patent:

6150680, Nov 21, 2000

Filed:

Mar 5, 1998

Appl. No.:

9/035475

Inventors:

Lester Fuess Eastman - Ithaca NY
James Richard Shealy - Ithaca NY

Assignee:

Welch Allyn, Inc. - Skaneateles Falls NY

International Classification:

H01L 2972

US Classification:

257224

Abstract:

A field effect semiconductor device including a substrate, a dipole barrier formed on the substrate, a channel layer formed on the dipole barrier, and source, gate and drain electrodes formed on the channel layer. The dipole barrier provides a potential barrier and a maximum electric field sufficient to confine electrons to the channel layer.

US Patent:

45645094, Jan 14, 1986

Filed:

Jun 30, 1983

Appl. No.:

6/509871

Inventors:

James R. Shealy - Ithaca NY
Lester F. Eastman - Ithaca NY

Assignee:

Northeast Semiconductor Inc. - Ithaca NY

International Classification:

B01D 4702

US Classification:

4232105

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.

US Patent:

43989632, Aug 16, 1983

Filed:

Nov 19, 1980

Appl. No.:

6/208596

Inventors:

Richard A. Stall - Summit NJ
Colin E. C. Wood - Freeville NY
Lester F. Eastman - Ithaca NY

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H01L 21265
H01L 29261
H01L 2348
H01L 754

US Classification:

148 15

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.

US Patent:

47003537, Oct 13, 1987

Filed:

Aug 12, 1985

Appl. No.:

6/764704

Inventors:

Edward Van Gieson - Ithaca NY
Gary W. Wicks - New Field NY
Eric Elias - Ithaca NY
Lester F. Eastman - Ithaca NY

Assignee:

Cornell Research Foundation, Inc. - Ithaca NY

International Classification:

H01S 310
H01S 319

US Classification:

372 26

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. Quenching is produced by means of energy shifts in the gain spectra of the laser device, and since current flow through the PN junction is inhibited by the nonconductive material and thus flows primarily in the quantum wells, modulation of the current is possible at microwave frequencies at relatively low power levels.

Author:

Lester F. Eastman

ISBN #:

0819403393