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Spin Valve Transistor with Planar Collector Interface and Method for producing the same

IP.com Disclosure Number: IPCOM000019593D
Publication Date: 2003-Sep-22
Document File: 4 page(s) / 75K

Publishing Venue

The IP.com Prior Art Database

Abstract

Spin Valve Transistor with Planar Collector Interface and Method for producing the same

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  Spin Valve Transistor with Planar Collector Interface and Method for producing the same

  A spin valve transistor (SVT) is a spin injection device which has spin oriented electrons injected over a barrier into a free layer, and is used as a magnetic field sensor device. Those spin oriented electrons that are not spin scattered continue and then traverse a second barrier. The current over the second barrier is referred to as the magneto-current. Conventional devices are constructed using silicon wafer bonding to define the barriers and thus create a planar surface at the collector barrier.

Conventional spin valve transistors are constructed using a traditional three-terminal framework having an emitter/base/collector structure of a bipolar transistor. SVTs further include at least a ferromagnetic layer, whereby the collector current is controlled by the magnetic state of the ferromagnetic layer which alters the spin-dependent scattering of the electrons.

A conventional SVT is described. Figure 1 illustrates a conventional SVT having a semiconductor collector region, an emitter region, and a base region. The base layer can contain a metallic spin valve. The semiconductors and magnetic materials used may include an n-type Si as an emitter and collector, and a Ni80Fe20/Au/Co spin valve in the base region. Energy barriers, also referred to as Schottkey barriers, are formed at the junctions between the metal base and the semiconductors. One can also use tunnel barriers between the layers of the device in place of a Shottkey barrier. A bias on the emitter will increase the current through the device.

It is desirable to obtain a high quality energy barrier and pattern the SVT to sub-micron dimensions. The ability to pattern such a device requires that the surface be planar. To ach...