Method of making a strained semiconductor device
In a method of making a semiconductor device, a recess is formed in an upper surface of the semiconductor body of a first material. An embedded semiconductor region is formed in the recess. The embedded semiconductor region is formed from a second semiconductor material that is different than the first semiconductor material. An upper surface of the embedded semiconductor region is amorphized to create an amorphous region. A silicide is then formed over the amorphous region.
1 . A method of making a semiconductor device, the method comprising:
providing a semiconductor body including an upper surface, the semiconductor body comprising a first semiconductor material;
creating a recess in the upper surface of the semiconductor body;
forming an embedded semiconductor region in the recess, the embedded semiconductor region comprising a second semiconductor material that is different than the first semiconductor material;
amorphizing an upper surface of the embedded semiconductor region to create an amorphous region; and
forming a silicide over the amorphous region.
2 . The method of claim 1 , wherein the first semiconductor material comprises silicon and the second semiconductor material comprises silicon germanium.
3 . The method of claim 2 , further comprising forming a silicon cap layer over the embedded semiconductor region before amorphizing the upper surface.
4 . The method of claim 3 , wherein amorphizing the upper surface is performed to a depth such that the amorphous region is located entirely within the silicon cap layer.
5 . The method of claim 2 , wherein forming the embedded semiconductor region comprises epitaxially growing silicon germanium using SiH 4 as a silicon source gas and GeH 4 as a germanium source gas.
6 . The method of claim 1 , wherein forming the embedded semiconductor region comprises selectively growing silicon as the second semiconductor material in the recess.
7 . The method of claim 1 , wherein amorphizing the upper surface comprises performing an implantation step.
8 . The method of claim 7 , wherein amorphizing the upper surface comprises implanting germanium ions into the embedded semiconductor region.
9 . The method of claim 7 , wherein amorphizing the upper surface comprises implanting xenon ions into the embedded semiconductor region.
10 . The method of claim 7 , wherein amorphizing the upper surface comprises implanting carbon ions into the embedded semiconductor region.
11 . The method of claim 1 , wherein forming the embedded semiconductor region comprises in situ doping of the embedded semiconductor region.
12 . The method of claim 1 , wherein forming a silicide comprises depositing a metal layer over the embedded semiconductor region and heating the region to form the silicide.
13 . The method of claim 12 , wherein the metal layer comprises a nickel layer.
14 . The method of claim 1 , wherein the first semiconductor material is silicon and the second semiconductor material is silicon carbon.
15 . A method of making a semiconductor device, the method comprising:
forming a recess in an upper surface of a silicon wafer;
growing an embedded silicon germanium region;
implanting a material to form an amorphous region over the silicon germanium region; and
forming a silicide over the amorphous region.
16 . The method of claim 15 , further comprising forming a silicon cap layer over the embedded silicon germanium region prior to implanting the material.
17 . The method of claim 16 , wherein the amorphous region is formed in the silicon cap layer.
18 . The method of claim 16 , wherein the amorphous region is formed entirely in the silicon cap layer.
19 . The method of claim 15 , wherein forming a silicide comprises depositing a metal layer over the embedded semiconductor region and heating the region to form the silicide.
20 . The method of claim 19 , wherein the metal layer comprises a nickel layer.
21 . A method of making a semiconductor device, the method comprising:
providing a semiconductor body including an upper surface, the semiconductor body comprising a first semiconductor material;
forming a gate electrode overlying the upper surface of the semiconductor body and insulated therefrom;
forming spacers adjacent to sidewalls of the gate electrode;
creating first and second recesses in the upper surface of the semiconductor body, the first recess being spaced from the second recess by the gate electrode;
forming embedded semiconductor source/drain regions in the first and second recesses, the embedded semiconductor source/drain regions each comprising a second semiconductor material that is different than the first semiconductor material;
amorphizing an upper surface of the embedded semiconductor source/drain regions to create an amorphous region; and
forming a silicide over the amorphous region.
22 . The method of claim 21 , wherein forming embedded semiconductor source/drain regions comprises forming p-doped embedded semiconductor source/drain regions.
23 . The method of claim 22 , wherein the first material is silicon and the second material is silicon germanium.
24 . The method of claim 23 , further comprising forming a silicon cap layer over the embedded semiconductor source/drain regions prior to amorphizing the upper surface.
25 . The method of claim 23 , wherein forming a silicide comprises forming nickel silicide.
26 . The method of claim 21 , further comprising forming a stress-inducing layer over the upper surface after forming the silicide.
27 . The method of claim 21 , wherein making a semiconductor device comprises making a field effect transistor with a channel length that is less than 65 nm.