Method for forming fully relaxed silicon germanium on silicon
View Patent ↗Semiconductor devices are formed with a thin layer of fully strain relaxed epitaxial silicon germanium on a substrate. Embodiments include forming a silicon germanium (SiGe) epitaxial layer on a semiconductor substrate, implanting a dopant into the SiGe epitaxial layer, and annealing the implanted SiGe epitaxial layer.
1. A method comprising:
forming a silicon germanium (SiGe) epitaxial layer having a thickness less than 200 nm on a semiconductor substrate;
ion implanting a dopant into the SiGe epitaxial layer; and
annealing the implanted SiGe epitaxial layer at a temperature of 400° C. to 1350° C.,
wherein the annealed SiGe has a threading dislocation density less than 1e6/cm2, and
wherein the annealed SiGe has a degree of strain relaxation greater than 90%.
2. The method according to claim 1 , comprising forming the SiGe epitaxial layer on a single crystalline silicon substrate.
3. The method according to claim 1 , comprising forming the SiGe epitaxial layer on a silicon-on-insulator (SOI) substrate.
4. The method according to claim 1 , comprising implanting arsenic (As), germanium (Ge), or boron (B) into the SiGe epitaxial layer.
5. The method according to claim 1 , comprising forming the SiGe epitaxial layer with 10 atomic % to near 100 atomic % Ge.
6. The method according to claim 1 , comprising annealing the implanted SiGe epitaxial layer by rapid thermal anneal or a furnace anneal.
7. The method according to claim 1 , comprising forming the SiGe epitaxial layer on the semiconductor substrate by blanket epitaxy.
8. The method according to claim 1 , comprising forming the SiGe epitaxial layer on the semiconductor substrate by selective epitaxy.
9. A device comprising:
a semiconductor substrate; and
a SiGe epitaxial layer having a thickness less than 200 nm, implanted with a dopant, formed on the semiconductor substrate,
wherein the implanted SiGe epitaxial layer has a degree of strain relaxation greater than 90% and wherein the implanted SiGe epitaxial layer has a threading dislocation density less than 1e6/cm2.
10. The device according to claim 9 , wherein the dopant comprises As, Ge, or B.
11. The device according to claim 9 , wherein the SiGe epitaxial layer comprises 10 atomic % to near 100 atomic % Ge.
12. A method comprising:
epitaxially growing asilicon germanium (SiGe) layer to a thickness less than 100 nm on a silicon or silicon-on-insulator (SOI) substrate, the SiGe having 10 atomic % to near 100 atomic % Ge;
ion implanting a dopant at a dose of 1E11/cm2 to 2E15/cm2 into the SiGe layer; and
thermally annealing the implanted SiGe epitaxial layer at a temperature of 400° C. to 1350° C.,
wherein the annealed SiGe layer has a threading dislocation density less than 1e6/cm2, and a degree of strain relaxation greater than 90%.
13. The method according to claim 12 , comprising implanting arsenic (As) into the SiGe layer.
14. The method according to claim 12 , comprising implanting germanium (Ge) into the SiGe layer.