A novel method for synthesizing device-quality alloys and ordered phases in a Si—Ge—Sn system uses a UHV-CVD process and reactions of SnD 4 with SiH 3 GeH 3 . Using the method, single-phase Si x Sn y Ge 1-x-y semiconductors (x≦0.25, y≦0.11) are grown on Si via Ge 1-x Sn x buffer layers The Ge 1-x Sn x buffer layers facilitate heteroepitaxial growth of the Si x Sn y Ge 1-x-y films and act as compliant templates that can conform structurally and absorb the differential strain imposed by the more rigid Si and Si—Ge—Sn materials. The SiH 3 GeH 3 species was prepared using a new and high yield method that provided high purity semiconductor grade material.
1. A semiconductor structure comprising: a substrate, a Sn z Ge 1-z layer formed over the substrate, and an essentially single-phase Ge 1-x-y Si x Sn y layer formed over the Sn z Ge 1-z layer.
2. The semiconductor structure of claim 1 wherein the substrate comprises silicon.
3. A method for synthesizing a compound having the molecular formula H 3 Si—GeH 3 , the method comprising combining H 3 SiO 3 SCF 3 with KGeH 3 under conditions whereby H 3 Si—GeH 3 is obtained.
4. The structure of claim 1 , wherein z is about 0.01 to about 0.05.
5. The structure of claim 1 , wherein x is about 0.01 to about 0.25; and y is about 0.01 to about 0.11.
6. The structure of claim 1 , wherein x is about 0.01 to about 0.25; y is about 0.01 to about 0.11; z is about 0.01 to about 0.05; and the substrate comprises silicon.
7. The structure of claim 1 , wherein the Ge 1-x-y Si x Sn y layer is strained.
8. The structure of claim 1 , wherein the Ge 1-x-y Si x Sn y layer is relaxed.
9. A method to prepare a semiconductor structure comprising the steps of,
providing a substrate;
depositing a Sn z Ge 1-z layer over the substrate; and
depositing an essentially single-phase Ge 1-x-y Si x Sn y layer over the Sn z Ge 1-z layer.
10. The method of claim 9 , wherein the Ge 1-x-y Si x Sn y layer is deposited by precursor chemical vapor deposition, wherein the precursor chemical vapor comprises SnD 4 and H 3 SiGeH 3 .
11. The method of claim 9 , wherein the Sn z Ge 1-z layer is deposited by precursor chemical vapor deposition, wherein the precursor chemical vapor comprises SnD 4 and Ge 2 H 6 .
12. The method of claim 9 , wherein the substrate comprises silicon.
13. The method of claim 9 , further comprising the step of annealing the Sn z Ge 1-z layer prior to depositing the Ge 1-x-y Si x Sn y layer.
14. The method of claim 9 , wherein z is about 0.01 to about 0.05.
15. The method of claim 9 , wherein x is about 0.01 to about 0.25; and y is about 0.01 to about 0.11.
16. The method of claim 9 , wherein x is about 0.01 to about 0.25; y is about 0.01 to about 0.11; z is about 0.01 to about 0.05; and the substrate comprises silicon.
17. The method of claim 9 , wherein the Ge 1-x-y Si x Sn y layer is deposited at a temperature of about 310° C. to about 375° C.
18. The method of claim 3 , wherein the H 3 SiO 3 SCF 3 and KGeH 3 are combined at about −60° C.
19. An alloy of the formula, Ge 1-x-y Si x Sn y , wherein x is about 0.01 to about 0.25 and y is about 0.01 to about 0.11.
20. The alloy of claim 19 , wherein x is about 0.13 to about 0.20.
21. The alloy of claim 20 , wherein y is about 0.07 to about 0.11.
22. The alloy of claim 20 , wherein y is about 0.01 to about 0.06.
23. A semiconductor structure comprising: a substrate, a Sn z Ge 1-z layer formed over the substrate, and a layer of an alloy of the formula, Ge 1-x-y Si x Sn y , wherein x is about 0.01 to about 0.25 and y is about 0.01 to about 0.11 formed over the Sn z Ge 1-z layer.
24. The semiconductor structure of claim 23 wherein the substrate comprises silicon.
25. The semiconductor structure of claim 1 wherein the Sn z Ge 1-z and Ge 1-x-y Si x Sn y layers are lattice-matched.
26. The semiconductor structure of claim 23 wherein the Sn z Ge 1-z and Ge 1-x-y Si x Sn y layers are lattice-matched.