Structures and devices including germanium-tin films and methods of forming same

• US 9,793,115 B2
• Filed: 07/06/2016
• Issued: 10/17/2017
• Est. Priority Date: 08/14/2013
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Tolle, John
• Primary Examiner(s): SMITH, BRADLEY
• Application Number:
  US15/203,642
• Publication Number:
  US 20160314967A1
• Time in Patent Office: 468 Days
• CPC Class Codes: C30B 25/183 being provided with a buffer layer, e.g. a lattice matching layer
• CPC Class Codes: C30B 29/52 Alloys
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0245 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02535 including tin
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 29/161 including two or more of the elements provided for in group H01L29/16 , e.g. alloys H01L29/1604 takes precedence
• CPC Class Codes: H01L 29/165 in different semiconductor regions , e.g. heterojunctions
• CPC Class Codes: H01L 31/0745 comprising a AIVBIV heterojunction, e.g. Si/Ge, SiGe/Si or Si/SiC solar cells
• CPC Class Codes: H01L 31/1812 including only AIVBIV alloys, e.g. SiGe
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

Methods of forming germanium-tin films using germane as a precursor are disclosed. Exemplary methods include growing films including germanium and tin in an epitaxial chemical vapor deposition reactor, wherein a ratio of a tin precursor to germane is less than 0.1. Also disclosed are structures and devices including germanium-tin films formed using the methods described herein.

Claims

1. A method of forming a crystalline germanium-tin layer, the method comprising the steps of:

providing a gas-phase reactor;

providing a germane (GeH₄) source coupled to the gas-phase reactor;

providing a tin precursor source coupled to the gas-phase reactor;

providing a substrate within a reaction chamber of the gas-phase reactor;

providing germane and a tin precursor to the reaction chamber, wherein a volumetric ratio of the tin precursor to the germane is about 0.001 to about 0.1; and

forming a crystalline layer of germanium tin on a surface of the substrate in a reaction chamber at a pressure between about 300 Torr and about 850 Torr, without using an etchant during the step of forming a crystalline layer.

2. The method of forming a crystalline germanium-tin layer according to claim 1, wherein the crystalline layer of germanium tin comprises silicon and the method further comprises:

providing a silicon source precursor.

3. The method of forming a crystalline germanium-tin layer according to claim 2, wherein the step of providing a silicon source precursor comprises providing a precursor selected from the group consisting of:

disilane, trisilane, tetrasilane, and neopentasilane.

4. The method of forming a crystalline germanium-tin layer according to claim 1, wherein, during the step of growing a crystalline layer of germanium tin on a surface of the substrate, an operating pressure of the reaction chamber is about 400 Torr to about 800 Torr.

5. The method of forming a crystalline germanium-tin layer according to claim 1, wherein, during the step of growing a crystalline layer of germanium tin on a surface of the substrate, an operating pressure of the reaction chamber is about 500 Torr to about 760 Torr.

6. The method of forming a crystalline germanium-tin layer according to claim 1, wherein, during the step of growing a crystalline layer of germanium tin on a surface of the substrate, an operating pressure of the reaction chamber is ambient atmospheric pressure±

about 20 Torr.

7. The method of forming a crystalline germanium-tin layer according to claim 1, wherein the volumetric ratio of the tin precursor to the germane is about 0.005 to about 0.05.

8. The method of forming a crystalline germanium-tin layer according to claim 1, wherein, during the step of growing a crystalline layer of germanium tin on a surface of the substrate, an operating temperature within the reaction chamber is about 200°

C. to about 500°

C.

9. The method of forming a crystalline germanium-tin layer according to claim 1, wherein, during the step of growing a crystalline layer of germanium tin on a surface of the substrate, an operating temperature within the reaction chamber is about 250°

C. to about 450°

C.

10. The method of forming a crystalline germanium-tin layer according to claim 1, wherein the step of providing a tin precursor source comprises providing a tin source selected from the group consisting of SnCl₄, SnD₄, and a methyl and halide substituted stannate.

11. The method of forming a crystalline germanium-tin layer according to claim 1, wherein the step of growing a crystalline layer of germanium tin on a surface of the substrate comprises growing a crystalline layer comprising about 2 at % to about 15 at % tin.

12. The method of forming a crystalline germanium-tin layer according to claim 1, wherein a ratio of the tin precursor to the germane precursor is less than 0.05.

13. A method of forming a structure comprising a germanium-tin layer, the method comprising the steps of:

forming an insulating layer overlying the substrate;

forming a via within the insulating layer;

providing a gas-phase reactor;

providing a substrate within a reaction chamber of the gas-phase reactor;

forming a crystalline layer comprising germanium tin on a surface of the substrate using one or more precursors comprising germane, wherein a pressure within the reaction chamber is between about 300 Torr and about 850 Torr; and

selectively forming the crystalline layer comprising germanium tin within the via.

14. The method of forming a structure comprising a germanium-tin layer of claim 13, wherein the substrate comprises a layer comprising germanium overlying silicon.

15. The method of forming a structure comprising a germanium-tin layer of claim 13, wherein the germanium-tin layer comprises from about 2 at % tin to about 15 at % tin.

16. The method of forming a structure comprising a germanium-tin layer of claim 13, wherein the step of forming does not include exposure of the substrate to an etchant.

17. The method of forming a structure comprising a germanium-tin layer of claim 13, wherein the substrate comprises a layer comprising germanium silicon tin overlying silicon.

18. The method of forming a structure comprising a germanium-tin layer of claim 13, wherein a volumetric ratio of a tin precursor to a germane is about 0.001 to about 0.1 during the step of forming a crystalline layer.

19. A structure comprising a crystalline layer of germanium tin formed according to the method of claim 13.

20. The structure comprising a crystalline layer of germanium tin of claim 19, wherein the structure comprises a germanium tin layer between two layers of germanium silicon tin.