P-type semiconductor devices
AssigneeQinetiq Limited
InventorDavid John Wallis
Life of this patent
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Abstract
A semiconductor device comprises an active layer above a first confinement layer. The active layer comprises a layer of α-Sn less than 20 nm thick. The first confinement layer is formed of material with a wider band gap than α-Sn, wherein the band gap offset between α-Sn and this material allows confinement of charge carriers in the active layer so that the active layer acts as a quantum well. A similar second confinement layer may be formed over the active layer. This semiconductor device may be a p-FET. A method of fabricating such a semiconductor device is described.
Claims18
A semiconductor device comprising:
- an active layer comprising a layer of α-Sn less than 20 nm thick;
- a first confinement layer below the active layer, wherein the first confinement layer is formed of a material or materials with a wider band gap than α-Sn, wherein the band gap offset between α-Sn and said material or materials allows confinement of charge carriers in the active layer so that the active layer acts as a quantum well;
- a second confinement layer above the active layer;
- a source;
- a drain;
- and
- a gate, the source, the drain and the gate all disposed over the second confinement layer, such that the gate is positioned between the source and the drain to control current in a p-channel between the source and the drain;
- wherein the semiconductor device is a p-FET.
A method of fabricating a semiconductor device, wherein the semiconductor device is a p-FET, comprising the steps of:
- preparing a substrate;
- growing a first confinement layer directly or indirectly on the substrate by an epitaxial growth process;
- growing an active layer of α-Sn over the first confinement layer by an epitaxial growth process;
- growing a second confinement layer over the active layer of α-Sn by an epitaxial growth process;
- and
- forming metal source, drain and gate pads over the second confinement layer by lithographic processes to form the p-FET of which the active layer forms the p-channel;
- wherein:
- the first confinement layer is formed of a material or materials with a wider band gap than α-Sn, wherein the band gap offset between α-Sn and said material or materials allows confinement of charge carriers in the active layer so that the active layer acts as a quantum well, and
- the second confinement layer is also formed of a material or materials with a wider band gap than α-Sn, wherein the band gap offset between α-Sn and said material or materials allows confinement of charge carriers in the active layer.
Dependencies are inferred from the claim text.