Spin transistor using stray magnetic field

A spin transistor comprising:

• a semiconductor substrate having a channel layer formed therein;
• first and second electrodes which are formed to be spaced apart from each other on the substrate at a predetermined distance along a longitudinal direction of the channel layer;
• a first ferromagnetic region and a second ferromagnetic region which include magnetized ferromagnetic materials and are formed to be spaced apart form each other between the first electrode and the second electrode at a predetermined distance along the longitudinal direction of the channel layer, the first and second ferromagnetic regions being physically separated from the first and second electrodes and producing stray magnetic fields vertical to a top surface of the channel layer;
• and
• a gate which is formed on the substrate between the first and second ferromagnetic regions, and adjusts spin orientations of electrons passing through the channel layer, wherein the gate is insulated from the substrate by a gate oxide on the substrate, and the first and second ferromagnetic regions are disposed below the level of the gate oxide,
• wherein the electrons passing through the channel layer are spin-aligned at a lower side of the first ferromagnetic region by a stray magnetic field of the first ferromagnetic region and spin-filtered at a lower side of the second ferromagnetic region by a stray magnetic field of the second ferromagnetic region, and
• the electrons which arrive at the lower side of the second ferromagnetic region are spin-adjusted to be parallel or anti-parallel to the direction of the stray magnetic field of the second ferromagnetic region by a voltage applied to the gate, in order to control an ON/OFF operation of the spin transistor.

A spin transistor comprising:

• a semiconductor substrate having a channel layer formed therein;
• first and second electrodes which are formed to be spaced apart from each other on the substrate at a predetermined distance along a longitudinal direction of the channel layer;
• a first ferromagnetic region and a second ferromagnetic region which include magnetized ferromagnetic materials and are formed to be spaced apart form each other between the first electrode and the second electrode at a predetermined distance along the longitudinal direction of the channel layer, the first and second ferromagnetic regions being physically separated from the first and second electrodes and producing stray magnetic fields vertical to a top surface of the channel layer;
• and
• a gate which is formed on the substrate between the first and second ferromagnetic regions, and adjusts spin orientations of electrons passing through the channel layer, wherein the gate is insulated from the substrate by a gate oxide on the substrate, and the first and second ferromagnetic regions are disposed below the level of the gate oxide,
• wherein the electrons passing through the channel layer are spin-aligned at a lower side of the first ferromagnetic region by a stray magnetic field of the first ferromagnetic region and spin-filtered at a lower side of the second ferromagnetic region by a stray magnetic field of the second ferromagnetic region,
• the electrons which arrive at the lower side of the second ferromagnetic region are spin-adjusted to parallel or anti-parallel to the direction of the stray magnetic field of the second ferromagnetic region by a voltage applied to the gate, in order to control an ON/OFF operation of the spin transistor,
• the transistor is turned on when the spin orientation of the electrons which arrive at the lower side of the second ferromagnetic region is anti-parallel to the direction of the stray magnetic field of the second ferromagnetic region.