Multiple gate semiconductor device and method for forming same
In accordance with an embodiment of the invention, a FinFET device is disclosed which comprises a strained silicon channel layer formed on, at least, the sidewalls of a strain-relaxed silicon-germanium body.
1 . A semiconductor device comprising:
a substrate;
a first contact region and a second contact region formed on the substrate;
a semiconductor fin in between and connecting the first contact region and the second contact region, the semiconductor fin having a body comprising a strain-relaxed material, the body having a surface, the surface not facing the substrate.
2 . The semiconductor device of claim 1 wherein the strain-relaxed material is an Si 1-y Ge y alloy with 0<y<1.
3 . The semiconductor device of claim 2 further comprising a layer, the layer at least partially overlapping the body, and the layer being lattice mismatched with the underlying strain-relaxed body.
4 . The semiconductor device of claim 3 wherein the overlapping layer at least covers those parts of the surface of the body, which are oblique to the substrate.
5 . The semiconductor device of claim 3 wherein the overlapping layer covers substantially the entire surface.
6 . The semiconductor device of claim 3 further comprising a gate, which at least partially, straddles the semiconductor fin.
7 . The semiconductor device of claim 6 wherein the first contact region is a source region and the second contact region is a drain region of a Field Effect Transistor.
8 . The semiconductor device of claim 3 wherein the layer comprises one or more elements selected from the atomic groups III, IV or V.
9 . The semiconductor device of claim 8 , wherein one of the elements is germanium.
10 . The semiconductor device of claim 8 , wherein one of the elements is silicon.
11 . The semiconductor device of claim 8 , wherein the layer comprises AlAs, GaAs or AlGaAs.
12 . The semiconductor device of claim 1 further comprising a layer, the layer at least partially overlapping the body, and the layer being lattice mismatched with the underlying strain-relaxed body.
13 . A method for manufacturing a semiconductor device having a fin, the fin comprising a strain-relaxed body, comprising:
providing a substrate, wherein the substrate comprises a source, a drain, and a fin in between, and connecting, the source and the drain, the fin having a body being formed of a first semiconductor material; the fin having a surface not facing the substrate,
depositing, at least on those parts of the surface which are oblique to the substrate, an alloy layer comprising a second and a third semiconductor material;
at least partially oxidizing the alloy layer thereby forming an oxide of the second material and thereby converting the body of a first semiconductor material in to an alloy of the first and the third semiconductor materials, the alloy being a strain-relaxed material; and
removing the oxide of the second semiconductor material.
14 . The method of claim 13 further comprising the step of forming a layer comprising a fourth semiconductor material, the layer at least partially overlaying the body, and the layer being lattice mismatched with the underlying strain-relaxed body.
15 . The method of claim 14 wherein
the layer at least covers those parts of the surface which are oblique to the substrate.
16 . The method of claim 14 wherein the first and/or the second semiconductor materials comprise silicon.
17 . The method of claim 14 wherein the third semiconductor material comprises germanium.
18 . The method of claim 14 wherein the fourth semiconductor material is selected from the atomic groups III, IV or V.
19 . The method of claim 18 wherein the fourth semiconductor material comprises silicon.