IP Library › Granted Patent US 12,454,768
Granted Patent B1
US 12,454,768 · App. 18/941,479 · Granted Oct 28, 2025

Hybrid seed structure for crystal growth system

Inventor: Matthew Donofrio (Raleigh, NC)
Assignee: WOLFSPEED, INC.
C30B23/025C30B29/36
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Quick Facts
Patent No.
US 12,454,768
App. No.
18/941,479
Granted
Oct 28, 2025
Kind
B1
Abstract

An example seed structure, systems, and methods for conducting crystal growth processes are provided. In one example, the present disclosure provides an example seed structure for a silicon carbide crystal growth system. The seed structure includes a carrier layer. The carrier layer is silicon carbide. The seed structure includes a seed layer bonded to the carrier layer with a bond. The seed layer is crystalline silicon carbide. The seed layer provides a growth surface for growing a crystalline silicon carbide structure in a silicon carbide crystal growth process.

Claims (43)

1. A seed structure for a silicon carbide crystal growth system, wherein the seed structure comprises:

a carrier layer, the carrier layer comprising silicon carbide; and

a seed layer bonded to the carrier layer with a bond, wherein the seed layer comprises crystalline silicon carbide, wherein the bond comprises an electrostatic interaction at an interface between the carrier layer and the seed layer;

wherein the seed layer provides a growth surface for growing a crystalline silicon carbide structure in a silicon carbide crystal growth process.

2. The seed structure of claim 1 , wherein the carrier layer comprises polycrystalline silicon carbide and the seed layer comprises monocrystalline silicon carbide.

3. The seed structure of claim 1 , wherein the carrier layer comprises monocrystalline silicon carbide and the seed layer comprises monocrystalline silicon carbide.

4. The seed structure of claim 1 , wherein the bond comprises one or more covalent bonds.

5. The seed structure of claim 1 , wherein the bond comprises a plasma-activated bond.

6. The seed structure of claim 1 , wherein the bond is a direct bond between the carrier layer and the seed layer without an intervening structure.

7. A seed structure for a silicon carbide crystal growth system, wherein the seed structure comprises:

a carrier layer, the carrier layer comprising silicon carbide; and

a seed layer bonded to the carrier layer with a bond wherein the seed layer comprises crystalline silicon carbide, wherein the bond provides an interface between one or more of the carrier layer, the seed layer, and one or more intervening structures,

wherein the seed layer provides a growth surface for growing a crystalline silicon carbide structure in a silicon carbide crystal growth process.

8. The seed structure of claim 7 , wherein the one or more intervening structures comprise a ceramic forming polymer or a silicon layer.

9. The seed structure of claim 8 , wherein the one or more intervening structures comprises an oxide layer.

10. The seed structure of claim 9 , wherein the oxide layer has a thickness of about 1 nm to about 5 nm.

11. The seed structure of claim 9 , wherein the oxide layer has a thickness of about 5 nm to about 10 nm.

12. The seed structure of claim 7 , wherein the one or more intervening structures has a thickness of about 1 nm to about 5 μm.

13. The seed structure of claim 7 , wherein the one or more intervening structures has a thickness of about 200 nm to about 2 μm.

14. The seed structure of claim 1 , wherein the carrier layer has a thickness that is greater than a thickness of the seed layer.

15. The seed structure of claim 1 , wherein the carrier layer has a thickness that is at least five times greater than a thickness of the seed layer.

16. The seed structure of claim 1 , wherein the carrier layer has a thickness in a range of about 1 μm to about 1000 μm.

17. The seed structure of claim 1 , wherein the silicon carbide crystal growth process provides for growth of the crystalline silicon carbide structure on the growth surface of the seed layer at temperatures in a range of about 1500° C. to about 2500° C.

18. A method for conducting crystal growth processes, comprising:

providing a seed structure to a crystal growth system, the seed structure comprising a carrier layer, the carrier layer comprising silicon carbide, the seed structure comprising a seed layer with a bond to the carrier layer, wherein the seed layer comprises crystalline silicon carbide, wherein the bond provides an interface between one or more of the carrier layer, the seed layer and one or more intervening structures; and

conducting a crystal growth process to grow a crystalline silicon carbide structure on a growth surface of the seed structure.

19. The method of claim 18 , wherein the carrier layer comprises polycrystalline silicon carbide and the seed layer comprises monocrystalline silicon carbide.

20. The method of claim 18 , wherein the carrier layer comprises monocrystalline silicon carbide and the seed layer comprises monocrystalline silicon carbide.

21. The method of claim 18 , wherein the one or more intervening structures comprise a ceramic forming polymer or a silicon layer.

22. The method of claim 18 , wherein the one or more intervening structures comprise an oxide layer.

23. The method of claim 18 , wherein the one or more intervening structures has a thickness of about 1 nm to about 5 μm.

24. The method of claim 18 , wherein the carrier layer has a thickness that is greater than a thickness of the seed layer.

25. The method of claim 18 , wherein the carrier layer has a thickness that is at least five times greater than a thickness of the seed layer.

26. The method of claim 18 , wherein the carrier layer has a thickness in a range of about 150 μm to about 500 μm.

27. The method of claim 18 , wherein the seed layer has a thickness in a range of about 0.2 μm to about 200 μm.

28. The method of claim 18 , wherein the silicon carbide crystal growth process is conducted at a temperature in a range of about 1500° C. to about 2500° C.

29. The method of claim 18 , wherein the method further comprises:

providing a bulk seed structure of crystalline silicon carbide;

separating the seed layer from the bulk seed structure.

30. The method of claim 29 , wherein the method comprising separating the seed layer from the bulk seed structure comprises:

inducing a damage region beneath a surface of the bulk seed structure;

bonding the carrier layer to the surface of the bulk seed structure; and

separating the seed layer from the bulk seed structure at least partially along the damage region such that the seed layer remains bonded to the carrier layer after separating the seed layer from the bulk seed structure.

Assignments (6)
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Mar 26, 2026
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 075280/0919 →
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Sep 30, 2025
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 072992/0113 →
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Sep 30, 2025
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 072992/0381 →
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Sep 30, 2025
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 072992/0467 →
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Sep 30, 2025
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 072992/0588 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 12, 2024
From: DONOFRIO, MATTHEW
To: WOLFSPEED, INC.
Reel/Frame 069235/0920 →
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