Crystal ion-slicing of single-crystal films

• US 6,120,597 A
• Filed: 02/17/1998
• Issued: 09/19/2000
• Est. Priority Date: 02/17/1998
• Status: Expired due to Term

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Levy, Miguel, Osgood, Richard M. Jr.
• Primary Examiner(s): KUNEMUND, ROBERT M
• Application Number:
  US09/025,114
• Time in Patent Office: 945 Days
• Field of Search: 438/406, 438/407, 438/458, 216/62, 216/87, 117/3, 117/4, 117/915
• US Class Current: 117/3
• CPC Class Codes: C30B 29/60 characterised by shape
• CPC Class Codes: C30B 33/00 After-treatment of single crystals or homogeneous polycrystalline material with defined structure C30B31/00 takes precedence
• CPC Class Codes: H01L 21/2007 Bonding of semiconductor wafers to insulating substrates or to semiconducting substrates using an intermediate insulating layer H01L21/2011 takes precedence; bonding of semiconductor wafers to semiconductor wafers for junction formation H01L21/187
• CPC Class Codes: H01L 21/30604 Chemical etching
• CPC Class Codes: H01L 21/76254 with separation/delamination along an ion implanted layer, e.g. Smart-cut, Unibond
• CPC Class Codes: Y10S 117/915 Separating from substrate

Abstract

A method is provided for detaching a single-crystal film from an epilayer/substrate or bulk crystal structure. The method includes the steps of implanting ions into the crystal structure to form a damage layer within the crystal structure at an implantation depth below a top surface of the crystal structure, and chemically etching the damage layer to effect detachment the single-crystal film from the crystal structure. The method of the present invention is especially useful for detaching single-crystal metal oxide films from metal oxide crystal structures.

Claims

1. A method for detaching a single-crystal metal oxide film from a metal oxide crystal structure, said method comprising the steps of:

implanting ions into said crystal structure to form a damage layer within said crystal structure at an implantation depth below a top surface of said crystal structure, said top surface and said damage layer defining at least in part said single-crystal metal oxide film to be detached from said crystal structure; and

chemically etching said damage layer to effect detachment of said single-crystal film metal oxide from said crystal structure.

2. The method according to claim 1, wherein said crystal structure is an epilayer/substrate crystal structure having a metal oxide epilayer disposed on a growth-compatible substrate.

3. The method according to claim 2, wherein said ion implanting step comprises the step of implanting ions into said growth-compatible substrate to form a damage layer within said growth-compatible substrate at said implantation depth below said top surface of said epilayer/substrate crystal structure.

4. The method according to claim 2, wherein said ion implanting step comprises the step of implanting ions into said metal oxide epilayer to form a damage layer within said metal oxide epilayer at said implantation depth below said top surface of said epilayer/substrate crystal structure.

5. The method according to claim 2, wherein said metal oxide epilayer is a layer of magnetic garnet material.

6. The method according to claim 2, wherein said metal oxide epilayer is a layer of ferroelectric material.

7. The method according to claim 2, wherein said crystal structure is an epilayer/substrate crystal structure has a plurality of metal oxide epilayers disposed within said growth-compatible substrate.

8. The method according to claim 1, wherein said crystal structure is a bulk crystal structure including a metal oxide material.

9. The method according to claim 8, wherein said ion implanting step comprises the step of implanting ions into said bulk crystal structure to form a damage layer within said bulk crystal structure at said implantation depth below said top surface of said bulk crystal structure.

10. The method according to claim 8, wherein said metal oxide material is a magnetic garnet material.

11. The method according to claim 8, wherein said metal oxide material is a ferroelectric material.

12. The method according to claim 11, wherein said ferroelectric material is lithium niobate.

13. The method according to claim 12, wherein said etching step comprises the step of applying diluted hydrofluoric acid at room temperature.

14. The method according to claim 1, wherein said implanting step comprises the step of providing ions at a characteristic energy level which determines said implantation depth.

15. The method according to claim 1, wherein said ions are elemental ions.

16. The method according to claim 1, wherein said ions are chemically reactive ions.

17. The method according to claim 1, wherein said chemical etching step comprises the steps of:

immersing said damage layer in an etchant;

stirring said etchant; and

maintaining said etchant at a constant etching temperature.

18. The method according to claim 17, wherein said etching temperature is increased higher than room temperature to achieve a faster etching rate.

19. The method according to claim 1, further comprising the step of encapsulating said crystal structure prior to said chemical etching step to minimize damage to the single-crystal film in said chemical etching step.

20. The method according to claim 1, further comprising the step of rapid thermal annealing prior to said chemical etching step to minimize damage to the single-crystal film in said chemical etching step.

21. A method for detaching a single-crystal metal oxide film from a metal oxide crystal structure, comprising the steps of:

implanting ions into said crystal structure to form a damage layer within said crystal stricture at an implantation depth below a top surface of said crystal structure, said top surface and said damage layer defining at least in part said single-crystal metal oxide film to be detached from said crystal structure; and

exposing said damage layer to a rapid temperature increase to effect detachment of said single-crystal metal oxide film from said crystal structure.

22. The method according to claim 21, wherein said crystal structure is an epilayer/substrate crystal structure having a metal oxide epilayer disposed on a growth-compatible substrate.

23. The method according to claim 22, wherein said metal oxide epilayer is a layer of magnetic garnet material.

24. The method according to claim 22, wherein said metal oxide epilayer is a layer of ferroelectric material.

25. The method according to claim 21, wherein said metal oxide crystal structure is a bulk crystal structure including a metal oxide material.

26. The method according to claim 21, wherein said exposing step comprises the steps of:

increasing the temperature of said crystal structure from room temperature to a temperature within a first temperature range; and

maintaining said temperature of said crystal structure within said first temperature range to effect detachment of said single-crystal metal oxide film from said crystal structure.

27. The method according to claim 26, wherein said temperature increasing step is performed for less than 60 second.

28. The method according to claim 26, wherein said temperature maintaining step is performed for approximately 30 seconds.

29. The method according to claim 26, wherein said first temperature range is approximately 750 to 800°

C.

30. The method according to claim 21, further comprising the step of chemically treating said damage layer to enhance detachment of said single-crystal metal oxide film from said crystal structure.

31. The method according to claim 21, wherein said temperature exposing step comprises the step of low-temperature melting said damage layer to effect detachment of said single-crystal metal oxide film from said crystal structure.

32. The method according to claim 30, wherein said step of chemically treating said damage layer minimizes the magnitude of said rapid temperature increase required to effect detachment of said single-crystal metal oxide film from said crystal structure.

33. The method according to claim 32, wherein said temperature exposing step comprises the step of low-temperature melting said damage layer to effect detachment of said single-crystal metal oxide film from said crystal structure.

34. A method for detaching a single-crystal metal oxide film from a metal oxide crystal structure, said method comprising the steps of:

implanting ions into said crystal structure to form a damage layer within said crystal structure at an implantation depth below a top surface of said crystal structure, said top surface and said damage layer defining at least in part said single-crystal metal oxide film to be detached from said crystal structure;

bonding said crystal structure to a second substrate; and

exposing said damage layer to a rapid temperature increase to effect detachment of said single-crystal metal oxide film from said crystal structure.

35. The method according to claim 34, wherein said crystal structure includes a magnetic garnet material.

36. The method according to claim 34, wherein said crystal structure includes a ferroelectric material.

37. The method according to claim 34, wherein said second substrate is a low temperature melting material.

38. The method according to claim 34, wherein said exposing step comprises the steps of:

increasing the temperature of said crystal structure from room temperature to a temperature within a first temperature range; and

maintaining said temperature of said crystal structure within said first temperature range to effect detachment of said single-crystal metal oxide film from said crystal structure.

39. The method according to claim 38, wherein said temperature increasing step is performed for less than 60 second.

40. The method according to claim 38, wherein said temperature maintaining step is performed for approximately 30 seconds.

41. The method according to claim 38, wherein said first temperature range is approximately 750 to 800°

C.

42. The method according to claim 34, further comprising:

applying a bonding layer between said crystal structure and said second substrate; and

melting away said bonding layer to effect detachment of said single-crystal metal oxide film from said crystal structure.

43. The method according to claim 42, wherein said bonding layer is a low-temperature melting material.