Threading-dislocation-free nanoheteroepitaxy of Ge on Si using self-directed touch-down of Ge through a thin SiO2 layer
AssigneeStc.Unm
InventorsSang M. Han, Qiming Li
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Abstract
A method of forming a virtually defect free lattice mismatched nanoheteroepitaxial layer is disclosed. The method includes forming an interface layer on a portion of a substrate. A plurality of seed pads are then formed by self-directed touchdown by exposing the interface layer to a material comprising a semiconductor material. The plurality of seed pads, having an average width of about 1 nm to 10 nm, are interspersed within the interface layer and contact the substrate. An epitaxial layer is then formed by lateral growth of the seed pads over the interface layer.
Claims20
A method of forming a semiconductor layer comprising:
- forming an interface layer on a substrate comprising a substrate material;
- exposing the interface layer to a material comprising a semiconductor material to form a plurality of windows in the interface layer, wherein the plurality of windows expose portions of the substrate, and to form a plurality of seed pads on the portions of the substrate exposed by the plurality of windows;
- and
- forming a heteroepitaxial semiconductor layer comprising a heteroepitaxial semiconductor material different from the substrate material by lateral growth and coalescence of the seed pads such that the heteroepitaxial semiconductor layer is disposed over the interface layer, wherein
- each of the plurality of windows in the interface layer is about 2 nm to about 8 nm wide;
- and
- the heteroepitaxial semiconductor layer has a threading dislocation density of less than 1×108 cm−2.
A method of forming a semiconductor layer comprising:
- forming an interface layer on a substrate;
- exposing the interface layer to a material comprising a first semiconductor material to form a plurality of windows in the interface layer, wherein the plurality of windows expose portions of the substrate, and to form a plurality of seed pads comprising the first semiconductor material on the portions of the substrate exposed by the plurality of windows;
- and
- forming an epitaxial semiconductor layer comprising the first semiconductor material by lateral growth and coalescence of the seed pads such that the epitaxial semiconductor layer is disposed over the interface layer, wherein
- each of the plurality of windows in the interface layer is about 2 nm to about 8 nm wide;
- and
- the epitaxial semiconductor layer has a threading dislocation density of less than 1×108 cm−2.
A semiconductor device comprising:
- a substrate comprising a substrate material;
- an oxide layer disposed on a portion of the substrate;
- a plurality of seed pads comprising a first semiconductor material formed in a plurality of windows in the oxide layer that expose portions of the substrate by self-directed touchdown, wherein each of the plurality of windows is about 2 nm to about 8 nm wide;
- and
- a heteroepitaxial semiconductor layer comprising a heteroepitaxial semiconductor material disposed over the substrate, wherein
- the heteroepitaxial semiconductor layer is formed by lateral growth and coalescence of the seed pads over the oxide layer;
- the heteroepitaxial semiconductor material is different from the substrate material;
- and
- the heteroepitaxial semiconductor layer has a threading dislocation density of less than 1×108 cm−2.
Dependencies are inferred from the claim text.