Spin transistor
AssigneeIsis Innovation Limited
InventorJohn Francis Gregg
Life of this patent
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Abstract
A spin transistor (10) comprises a spin injector (50) formed of a ferromagnetic material and constituting the emitter (20) of a three-terminal device, a spin filter (70) also formed of a ferromagnetic material and constituting a collector (40), and a semiconductor base (30) region. A tunneling barrier (60) is formed of an insulating metal oxide such as aluminum oxide between the emitter (20) and the base (30). The tunneling barrier (60) reduces the degree of spin depolarization as carriers are injected into the base (30), and permits selection of spin injection energy. In preferred embodiments, a second tunneling barrier (80) may be formed between the base (30) and the collector (40). A method of manufacture is also provided.
Claims29
A spin transistor comprising a first region defining an emitter, a second region defining a semiconductor base, and a third region defining a collector, wherein:
- the emitter includes a spin polarizer for spin-polarizing charge carriers to be injected from the emitter to the base;
- and
- the collector includes a spin filter for spin-filtering charge carriers received at the collector from the base;
- characterised in that the emitter further includes a tunnelling barrier arranged to tunnel inject the spin-polarized charge carriers into the semiconductor base.
The spin transistor of any preceding claim, in which the spin polarizer is formed of a spin asymmetric material.
The spin transistor of any preceding claim, in which the spin filter is formed of a spin asymmetric material.
The spin transistor of any preceding claim, in which the base includes a further magnetic element.
The spin transistor of any preceding claim, in which the emitter tunnelling barrier is formed of Aluminium Oxide.
The spin transistor of any preceding claim, in which the emitter and collector are respectively formed on first and second opposing faces of a doped semiconductor layer of a silicon-on-insulator (SOI) wafer, the doped semiconductor layer constituting at least a part of the said semiconductor base.
A method of fabricating a spin transistor, comprising the steps of:
- (a) forming a first region defining an emitter having a-spin polarizer for spin-polarizing charge carriers to be injected from the emitter, and an emitter tunnelling barrier;
- (b) forming a second region defining a semiconductor base for receiving the spin-polarized charge carriers from the emitter via the emitter tunnel barrier;
- and
- (c) forming a third region defining a collector, the collector including a spin filter for spin-filtering charge carriers received at the collector from the base;
- wherein the base of the spin transistor thus fabricated is adjacent the emitter tunnelling barrier and the collector.
A spin transistor substantially as herein described with reference to and as shown in the accompanying drawings.
A method of fabricating a spin transistor substantially as herein described with reference to and as shown in the accompanying drawings.
Dependencies are inferred from the claim text.