Methods of forming silicon germanium tin films and structures and devices including the films
Methods of forming silicon germanium tin (Si x Ge 1-x Sn y ) films are disclosed. Exemplary methods include growing films including silicon, germanium and tin in an epitaxial chemical vapor deposition reactor. Exemplary methods are suitable for high volume manufacturing. Also disclosed are structures and devices including silicon germanium tin films.
1. A method of forming a Si x Ge 1-x Sn y layer on a substrate, the method comprising the steps of:
providing a reactor having a reaction space;
providing a substrate within the reaction space;
providing silane coupled to the reaction space;
providing a germanium precursor coupled to the reaction space;
providing a tin precursor source coupled to the reaction space; and
epitaxially forming a layer of Si x Ge 1-x Sn y on a surface of the substrate,
wherein a pressure in the reaction space is between about 500 Torr and about 760 Torr and a temperature in the reaction space is between about 200° C. and about 500° C.,
wherein a ratio of a flowrate of the silane to a flowrate of the tin precursor is between about 2 to about 15, and
wherein the Si x Ge 1-x Sn y layer comprises about 2 at % to about 15 at % tin, and about 55 at % to about 65 at % germanium.
2. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein the germanium precursor comprises germane.
3. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein, during the step of epitaxially forming a layer of Si x Ge 1-x Sn y on a surface of the substrate, an operating pressure of the reaction space is between about 600 Torr and about 760 Torr.
4. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein the layer of Si x Ge 1-x Sn y comprises about 3 at % to about 12 at % tin.
5. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein the layer of Si x Ge 1-x Sn y comprises greater than 0 to about 30 at % silicon.
6. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein the layer of Si x Ge 1-x Sn y comprises about 1 at % to about 2 at % carbon.
7. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein, during the step of epitaxially forming a layer of Si x Ge 1-x Sn y on a surface of the substrate, a ratio of the silane to the germanium precursor provided to the reaction space is about 2 to about 15.
8. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein, during the step of epitaxially forming a layer of Si x Ge 1-x Sn y on a surface of the substrate, a ratio of the silane to the germanium precursor provided to the reaction space is about 3 to about 12.
9. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein, during the step of epitaxially forming a layer of Si x Ge 1-x Sn y on a surface of the substrate, an operating temperature within the reaction space is about 275° C. to about 475° C.
10. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein the step of providing a tin precursor comprises providing a tin source selected from one or more of the group of SnCl 4 , SnD 4 , and a methyl and/or halide substituted stannate.
11. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein the step of epitaxially forming a layer of Si x Ge 1-x Sn y on a surface of the substrate comprises growing a crystalline layer comprising about 4 at % to about 5 at % carbon.
12. The method of forming a Si x Ge 1-x Sn y layer according to claim 1 , wherein the step of epitaxially forming a layer of Si x Ge 1-x Sn y on a surface of the substrate comprises growing a crystalline layer comprising 1 at % to about 30 at % silicon.
13. A method of forming a structure comprising a Si x Ge 1-x Sn y layer, the method comprising the steps of:
providing a cross-flow reactor comprising a reaction space;
providing a substrate within the reaction space; and
forming a crystalline layer comprising Si x Ge 1-x Sn y on a surface of the substrate using silane and germane,
wherein, during the step of forming, a pressure in the reaction space is between about 500 Torr and about 760 Torr and a temperature is between about 200° C. and about 500° C.,
wherein, during the step of forming, a ratio of the silane to the germane provided to the reaction space is about 2 to about 15,
wherein a ratio of a flowrate of the silane to a flowrate of a tin precursor is between about 2 to about 15, and
wherein the Si x Ge 1-x Sn y layer comprises about 2 at % to about 15 at % tin, and about 60 at % to about 70 at % germanium.
14. The method of forming a structure comprising a Si x Ge 1-x Sn y layer of claim 13 , wherein the substrate comprises a layer comprising germanium overlying silicon.
15. The method of forming a structure comprising a Si x Ge 1-x Sn y layer of claim 13 , wherein the layer comprising Si x Ge 1-x Sn y comprises about 3 from greater than 0 at % tin to about 12 at % tin.
16. The method of forming a structure comprising a Si x Ge 1-x Sn y layer of claim 13 , wherein the layer comprising Si x Ge 1-x Sn y comprises from greater than 0 at % silicon to about 30 at % silicon.
17. The method of forming a structure comprising a Si x Ge 1-x Sn y layer of claim 13 , wherein the layer comprising Si x Ge 1-x Sn y comprises about 2 at % germanium to about 3 at % carbon.
18. The method of forming a structure comprising a Si x Ge 1-x Sn y layer of claim 13 , further comprising the steps of:
forming an insulating layer overlying the substrate;
forming a via within the insulating layer, and
selectively forming the layer comprising Si x Ge 1-x Sn y within the via.
19. A structure comprising a crystalline layer of Si x Ge 1-x Sn y formed according to the method of claim 13 .
20. The structure of claim 19 , wherein the structure comprises a layer comprising germanium overlying the crystalline layer of Si x Ge 1-x Sn y .