Method for forming nitride crystals

• US 20080087919A1
• Filed: 10/05/2007
• Published: 04/17/2008
• Est. Priority Date: 10/08/2006
• Status: Active Grant

• Current Assignee: SL Technology Incorporated (Reliv' International, Inc.)
• Original Assignee: Momentive Performance Materials Incorporated (Momentive Performance Materials Holdings LLC)
• Inventors: Park, Dong-Sil, Hong, Huicong, Leman, John, D'Evelyn, Mark, Tysoe, Steven, Narang, Kristi
• Granted Patent: US 7,642,122 B2
• Time in Patent Office: Days
• US Class Current: 257/201
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 9/00 Single-crystal growth from melt solutions using molten solvents by normal or gradient freezing C30B11/00; by zone-melting C30B13/00; by crystal pulling C30B15/00; on immersed seed crystal C30B17/00; by liquid phase epitaxial growth C30B19/00; under a protective fluid C30B27/00

Abstract

A method for growing a nitride crystal and a crystalline composition selected from one of AlN, InGaN, AlGaInN, InGaN, and AlGaNInN is provided. The composition comprises a true single crystal, grown from a single nucleus, at least 1 mm in diameter, free of lateral strain and tilt boundaries, with a dislocation density less than about 10⁴ cm⁻².

Claims

1. A method for growing a nitride crystal which comprises:

providing source material containing less than 1 weight percent oxygen;

providing a mineralizer;

optionally, providing one or more seed crystals;

providing a capsule;

filling the capsule with a nitrogen-containing solvent;

processing the capsule and contents in a supercritical fluid at a temperature higher than about 550°

C. and a pressure higher than about 2 kbar.

2. The method of claim 1, wherein the source material is Al_xGa_1-x-yIn_yN, wherein 0≦

x, y, x+y≦

1, and at least one of x or y is greater than zero.

3. The method of claim 1, wherein the source material is Al_xGa_1-x-yIn_yN, wherein 0≦

x, y, x+y≦

1, and at least one of x or y is greater than 0.05.

4. The method of claim 1 wherein the source material is AlN.

5. The method of claim 1 wherein the mineralizer is at least one of (i) a nitride;

(ii) an amide;

(iii) a urea;

(iv) an ammonium salt;

(v) a halide, chalcogenide, or nitrate salt;

(vi) an azide salt and (vii) a Li salt.

6. The method of claim 5 wherein the mineralizer is at least one compound formed by chemical reaction of at least two compounds selected from components (i)-(vii).

7. The method of claim 5 wherein the mineralizer is at least one compound formed by chemical reaction of at least one of compound selected from components (i)-(vii) with AlN and/or Al.

8. The method of claim 5, wherein the mineralizer is at least one of HX, NH₄X, and GaX₃, wherein X is selected from the group consisting of F, Cl, Br, or I.

9. The method of claim 5, wherein the mineralizer is a reaction product of at least one of HX, NH₄X and GaX₃ with at least one of HX, NH₄X, GaX₃, Ga, GaN and NH₃, wherein X is selected from the group consisting of F, Cl, Br, or I.

10. The method of claim 1, wherein the mineralizer is at least one compound selected from the group consisting of Li₃N, Mg₃N₂, Ca₃N₂, LiNH₂, NaNH₂, KNH₂, NH₄F, NH₄Cl, NaCl, Li₂S, KNO₃, NaN₃ and Na₃AlF₆.

11. The method of claim 1, wherein the optional seed crystal is an AlN seed crystal or a non-AlN seed crystal.

12. The method of claim 1 wherein the seed is selected from the group consisting of InN, AlN, GaN, Ga_xIn_1-xN, SiC, Ga_xAl_1-xN, InAlN, Al_yGa_1-x-yIn_xN, ZnO, BN (Hexagonal), B_xGa_1-xN, B_xAl_1-xN, B_xIn_1-xN, MgAl2O4, BP, (Ga_xIn_1-x)₂Se₃, ScAlMgO4, YFeZnO4, MgO, Fe2NiO4, LiGa5O8, Na2MoO4, Na2WO4, In2CdO4, LiGaO2, Ca8La2(PO4)6O2 and sapphire.

13. The method of claim 1 wherein the optional seed crystal is larger than 1 mm in diameter.

14. The method of claim 1 wherein the nitrogen-containing solvent is ammonia.

15. A nitride crystal comprising a single crystal grown from a single nucleus having a diameter of at least 1 mm, free of lateral strain and tilt boundaries, with a dislocation density less than about 10⁴ cm⁻

2, wherein the nitride crystal is selected from the group consisting of InGaN, AlGaInN, InGaN, AlGaNInN, and AlN.

16. A wafer prepared from the nitride crystal of claim 15, wherein said wafer is sliced, lapped, and polished.

17. The wafer of claim 16, further comprising at least one epitaxial nitride layer.

18. The wafer of claim 17, wherein the epitaxial nitride layer comprises AlInGaN.

19. A homoepitaxial device prepared from the nitride crystal of claim 15.

20. The homoepitaxial device of claim 18, wherein said device is one of a light emitting diode, a laser diode, a photodetector, an avalanche photodetector, a field-effect transistor, a bipolar junction transistor and a thyristor.