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Spin transistor based on the spin-filter effect, and non-volatile memory using spin transistors

Foreign code F110005377
File No. K02003US3
Posted date Sep 5, 2011
Country United States of America
Application number 97922007
Gazette No. 20080067501
Gazette No. 7825485
Date of filing Oct 31, 2007
Gazette Date Mar 20, 2008
Gazette Date Nov 2, 2010
International application number JP2003009438
International publication number WO2004012272
Date of international filing Jul 25, 2003
Date of international publication Feb 5, 2004
Priority data
  • P2002-217336 (Jul 25, 2002) JP
  • P2003-086145 (Mar 26, 2003) JP
  • 2003WO-JP09438 (Jul 25, 2003) WO
  • 2005US-10522241 (Oct 5, 2005) US
Title Spin transistor based on the spin-filter effect, and non-volatile memory using spin transistors
Abstract (US7825485)
A spin transistor comprises a spin injector for injecting, from a first nonmagnetic electrode carriers with a spin parallel to a spin band forming the band edge of a first ferromagnetic barrier layer, to a second nonmagnetic electrode layer, as hot carriers.
It also comprises a spin analyzer whereby, due to spin-splitting at the band edge of a second ferromagnetic barrier layer, the spin-polarized hot carriers are transported to a third nonmagnetic electrode when the direction of the spin of the carriers injected into the second nonmagnetic electrode is parallel to that of the spin of the spin band at the band edge of the second ferromagnetic barrier layer, whereas the hot carriers are not transported to the third nonmagnetic electrode in the case of antiparallel spin.
A memory element is also provided that comprises such a spin transistor.
Scope of claims [claim1]
1. A transistor comprising a tunnel junction structure and a gate electrode, wherein said tunnel junction structure comprises: a tunnel barrier formed of an insulating nonmagnetic material;
a source formed of a ferromagnetic material; and
a drain formed of a ferromagnetic material, said tunnel barrier being disposed between said source and said drain, the source being joined to one end surface of said tunnel barrier and the drain being joined to the other end surface of said tunnel barrier,
wherein said gate electrode is formed over said tunnel barrier and configured to apply an electric field to the tunnel barrier, and
wherein the tunnel barrier is formed with a thickness such that Fowler-Nordheim tunneling does not occur when the gate electrode is not applying the electric field to the tunnel barrier and Fowler-Nordheim tunneling does occur when the gate electrode is applying the electric field to the tunnel barrier.
[claim2]
2. The transistor according to claim 1, wherein the ferromagnetic material used in said source and said drain is a ferromagnetic metal or a ferromagnetic semiconductor.
[claim3]
3. The transistor according to claim 1, wherein a thickness of said tunnel barrier is set to be such that a tunnel current can take place from said source to said drain with the application of a voltage to said gate electrode.
[claim4]
4. The transistor according to claim 1, wherein a magnitude of mutual conductance or an output current is controlled by relative magnetization directions of said source and said drain.
[claim5]
5. The transistor according to claim 1, wherein one of said source and said drain has a coercivity that is higher than that of the other of said source and said drain.
[claim6]
6. A transistor comprising a tunnel junction structure and a gate electrode, wherein said tunnel junction structure comprises: a tunnel barrier famed of an insulating nonmagnetic material;
a source formed of a ferromagnetic material; and
a drain formed of a ferromagnetic material, said tunnel barrier being disposed between said source and said drain, said source being joined to a first end surface of said tunnel barrier, said drain being joined to a second end surface of said tunnel barrier,
wherein said gate electrode is formed on said tunnel barrier and applies an electric field to the tunnel barrier, and
wherein the tunnel barrier has a thickness and an energy band edge that enables a carrier to pass through the tunnel barrier via Fowler-Nordheim tunneling from the source to the drain.
  • Inventor, and Inventor/Applicant
  • SUGAHARA SATOSHI
  • TANAKA MASAAKI
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
IPC(International Patent Classification)
Reference ( R and D project ) PRESTO Nanostructure and Material Property AREA
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