Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Magnetic field
Reexamination Certificate
1995-06-07
2001-10-23
Crane, Sara (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Magnetic field
C257S425000, C257S431000
Reexamination Certificate
active
06307241
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention is in the field of electronic and photonic circuitries. In particular, this invention relates to the implantation of submicron ferromagnetic precursors into semiconductors, to produce semiconductors with ferromagnetic activity.
BACKGROUND OF THE INVENTION
The discovery of spin-dependent electronic phenomena occurring in magnetic multilayers {Parkin, S. S. P., et al.,
Phys. Rev. Lett
., 66:2152-2155 (1991)} and granular solids {Xiao, J. Q., et al.,
Phys. Rev. Lett
., 68:3749-3752 (1992); Berkowitz, A. E., et al.,
Phys. Rev. Lett
., 68: 3745-3748 (1992)} is raising interesting scientific questions regarding spin interactions in reduced dimensional magnetic systems and giving rise to new device technologies. In particular, exploring magneto-electronic or -optical behavior within semiconducting compounds offers the exciting possibility of combining local magnetism with the flexibility of semiconductor-based quantum electronic structures {Prinz, G.,
Science
, 250:1092-1097 (1990)}. Recent attempts at including ferromagnetism in III-V semiconductors required atomically layered deposition under precise epitaxial growth conditions, yielding two-dimensional magnetic thin films. {Tanaka, M., et al.,
Appl. Phys. Lett
., 63:696-698 (1993)}.
SUMMARY OF THE INVENTION
One aspect of the invention presents a method for introducing ferromagnetic precursors into a substrate, preferably a semiconductor, which preferably allows the resulting product to behave as ferromagnets at room temperature. The ferromagnets are introduced into the substrate by means of ion implantation of the ferromagnetic precursors and subsequent annealing into ferromagnets. The method preferably preserves the integrity of the semiconductor, i.e. both the optical and current transport properties in the vicinity of the ferromagnets in the resulting product are the same, substantially the same, or similar, to the semiconductor substrate.
Another aspect of the invention presents materials which have ferromagnets incorporated onto, into and/or below their surfaces (herein collectively referred to as “integrated” into the product). The materials preferably possess Curie temperature above 400 K. These materials are preferably semiconductors, with ferromagnets integrated therein. More preferably, the semiconductors, with the integrated ferromagnets, bear electronic and photonic circuitries and can serve as an integrated unit for both disk and memory storage. The materials of this invention possess higher density of information storage than the currently available semiconductors. They are preferably made according to the method described in the preceding paragraph.
Another aspect of the invention presents devices made from or containing components comprising the above described materials.
REFERENCES:
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patent: 5191223 (1993-03-01), Munekata
patent: 5462809 (1995-10-01), Berkowitz
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N.W.Ashcroft et al., “Solid State Physics,” Saunders College, p. 697, 1976.*
Berkowitz, A. E., et al., “Giant Magnetoresistance in Heterogeneous Cu-Co Alloys”,Phys. Rev. Lett.,68:3745 (1992).
Binary Alloy Phase Diagram,2nd Ed., edited by Massalski, T.B., et al., (American Society for Metals, Metals Park, OH), 1:293 and references therein (1990).
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Kikkawa, J.M., et al., “Optical studies of locally implanted magnetic ions in GaAs”,Phys. Rev. B,50(3):2003 (1994).
Parkin, S. S. P., et al., “Oscillatory Magnetic Exchange Coupling through Thin Copper Layers”,Phys. Rev. Lett.,66:2152 (1991).
Prinz, G., “Hybrid Ferromagnetic-Semiconductor Structures”,Science, 250:1092 (1990).
Tanaka, M., et al., “Epitaxial MnGa/NiGa magnetic multilayers on GaAs”,Appl. Phys. Lett.,63:696 (1993).
Tsuboya, I., et al., “Magnetic Properties of &zgr;Phase in Mn-Ga System”,Phys. Soc. Jpn., 18:1096 (1993).
Xiao, J. Q., et al., “Giant Magnetoresistance in Nonmultilayer Systems”,Phys. Rev. Lett., 68:3749-3752 (1992).
Awschalom David D.
Kikkawa James M.
Petroff Pierre M.
Shi Jing
Crane Sara
Fulbright & Jaworski L.L.P.
The Regents of the Unversity of California
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