High quality group-III metal nitride crystals, methods of making, and methods of use

• US 9,589,792 B2
• Filed: 11/25/2013
• Issued: 03/07/2017
• Est. Priority Date: 11/26/2012
• Status: Active Grant

• Current Assignee: SL Technology Incorporated (Reliv' International, Inc.)
• Original Assignee: Soraa, Inc.
• Inventors: Jiang, Wenkan, D'Evelyn, Mark P., Kamber, Derrick S., Ehrentraut, Dirk, Krames, Michael
• Primary Examiner(s): Sample, David
• Assistant Examiner(s): Flores, Jr., Donald M
• Application Number:
  US14/089,281
• Publication Number:
  US 20140147650A1
• Time in Patent Office: 1,198 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 7/105 using ammonia as solvent, i.e. ammonothermal processes
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02642 Mask materials other than SiO2 or SiN
• CPC Class Codes: H01L 21/02647 Lateral overgrowth
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: Y02P 20/133 Renewable energy sources, e.g. sunlight

Abstract

High quality ammonothermal group III metal nitride crystals having a pattern of locally-approximately-linear arrays of threading dislocations, methods of manufacturing high quality ammonothermal group III metal nitride crystals, and methods of using such crystals are disclosed. The crystals are useful for seed bulk crystal growth and as substrates for light emitting diodes, laser diodes, transistors, photodetectors, solar cells, and for photoelectrochemical water splitting for hydrogen generation devices.

Claims

1. A group III metal nitride crystal made from a process comprising:

depositing at least one patterned mask layer on a substrate to form a patterned substrate, said mask layer comprising at least an inert layer comprising one or more of Au, Ag, Pt, Pd, Rh, Ru, Ir, Ni, Cr, V, Ti, or Ta, said inert layer being adhered to said substrate;

placing said patterned substrate within a sealable container along with a group III metal source, at least one mineralizer composition, and a nitrogen containing solvent; and

forming an ammonothermal group III metal nitride layer having one or more coalescence fronts on the patterned substrate by heating said sealable container, wherein said one or more coalescence fronts comprise a pattern of locally-approximately-linear arrays of threading dislocations, said threading dislocations having a concentration between about 5 cm<sup>−

1</sup> and about 10⁵ cm<sup>−

1</sup>, said pattern having;

at least one pitch dimension between about 5 micrometers and about 20 millimeters; and

regions between said locally-approximately-linear arrays of threading dislocations having a threading dislocation density below about 10⁵ cm<sup>−

2</sup> and a stacking-fault concentration below about 10³ cm<sup>−

1</sup>.

2. The crystal of claim 1, wherein the crystal comprises a group III metal selected from gallium, aluminum, indium, and a combination of any of the foregoing;

and nitrogen.

3. The crystal of claim 1, wherein the first large-area surface is characterized by, a symmetric x-ray rocking curve full width at half maximum less than about 200 arcsec;

an impurity concentration of H greater than about 10¹⁷ cm<sup>−

3</sup>; and

an impurity concentration greater than about 10¹⁵ cm<sup>−

3</sup> of at least one of Li, Na, K, F, CI, Br, and I, as quantified by calibrated secondary ion mass spectrometry.

4. A bulk crystal grown on the crystal of claim 1.

5. The crystal of claim 1, wherein said mask layer comprises a discrete adhesion layer to adhere said inert layer to said substrate.

6. The crystal of claim 1, wherein said mask layer comprises a discrete diffusion barrier layer.

7. The crystal of claim 1, wherein the pattern further comprises a one-dimensional or two-dimensional array of openings having an opening dimension between about 1 micrometer and about 5 millimeters.

8. The crystal of claim 1, wherein said crystal comprises a first large-area surface having a maximum dimension greater than about 10 millimeters.

9. The crystal of claim 1, wherein said mask layer has a thickness between about 10 nanometers and about 100 micrometers.

10. The crystal of claim 1, wherein said heating said sealable container comprises heating said sealable container to a temperature of at least about 400 degrees Celsius and pressurizing it to a pressure above about 50 MPa for a duration of at least 100 hours.

11. The crystal of claim 1, wherein said inert layer comprises at least Au.

12. The crystal of claim 1, wherein the substrate consists essentially of a free-standing, bulk, gallium nitride substrate.

13. A wafer formed from a bulk crystal grown on a seed crystal derived from a group III metal nitride crystal made from a process comprising:

depositing at least one patterned mask layer on a substrate to form a patterned substrate, said mask layer comprising at least an inert layer comprising one or more of Au, Ag, Pt, Pd, Rh, Ru, Ir, Ni, Cr, V, Ti, or Ta, said inert layer being adhered to said substrate;

placing said patterned substrate within a sealable container along with a group III metal source, at least one mineralizer composition, and a nitrogen containing solvent; and

forming an ammonothermal group III metal nitride layer having one or more coalescence fronts on the patterned substrate by heating said sealable container;

wherein said wafer is a free-standing ammonothermal group III metal nitride crystal, wherein the crystal is characterized by a wurtzite crystal structure, and comprises at least;

a group III metal selected from gallium, aluminum, indium, and a combination of any of the foregoing, and nitrogen; and

a first large-area surface having a maximum dimension greater than about 10 millimeters,

wherein the first large-area surface is characterized by,

a symmetric x-ray rocking curve full width at half maximum less than about 200 arcsec;

an impurity concentration of H greater than about 10¹⁷ cm<sup>−

3</sup>;

and an impurity concentration greater than about 10¹⁵ cm<sup>−

3</sup> of at least one of Li, Na, K, F, Cl, Br, I, as quantified by calibrated secondary ion mass spectrometry, wherein the first large-area surface comprises a pattern of locally-approximately-linear arrays of threading dislocations having a concentration between about 5 cm<sup>−

1</sup> and about 10⁵ cm<sup>−

1</sup>, and wherein the pattern is characterized by,

at least one pitch dimension between about 5 micrometers and about 20 millimeters; and

regions between said locally-approximately-linear arrays of threading dislocations having a threading dislocation density below about 10⁵ cm<sup>−

2</sup> and a stacking-fault concentration below about 10³ cm<sup>−

1</sup>.

14. The wafer of claim 13, wherein the first large-area surface is characterized by a crystallographic orientation within 5 degrees of a {10-10} m-plane.

15. The wafer of claim 13, wherein the first large-area surface is characterized by a crystallographic orientation within 5 degrees of a (0001) +c-plane or within 5 degrees of a (000−

1)−

c-plane.

16. The wafer of claim 13, wherein the first large-area surface is characterized by a crystallographic orientation within 5 degrees of a semipolar orientation selected from {60−

6±

1}, {50−

5±

1}, {40−

4±

1}, {30−

3±

1}, {50−

5±

2}, {70−

7±

3}, {20−

2±

1}, {30−

3±

2}, {40−

4±

3}, {50−

5±

4}, {10−

1±

1}, {1 0 −

1±

2}, {1 0 −

1±

3}, {2 1 −

3±

1}, and {3 0 −

3±

4}.

17. The wafer of claim 13, wherein the first large-area surface is characterized by impurity concentrations of oxygen (O), hydrogen (H), and at least one of fluorine (F) and chlorine (Cl) between about 1×

10¹⁶ cm<sup>−

3</sup> and about 1×

10¹⁹ cm<sup>−

3</sup>, between about 1×

10¹⁶ cm<sup>−

3</sup> and about 2×

10¹⁹ cm<sup>−

3</sup>, and between about 1×

10¹⁵ cm<sup>−

3</sup> and about 1×

10¹⁹ cm<sup>−

3</sup>, respectively.

18. The wafer of claim 13, wherein the first large-area surface is characterized by impurity concentrations of oxygen (O), hydrogen (H), and at least one of sodium (Na) and potassium (K) between about 1×

10¹⁶ cm<sup>−

3</sup>and about 1×

10¹⁹ cm<sup>−

3</sup>, between about 1×

10¹⁶ cm<sup>−

3</sup> and about 2×

10¹⁹ cm<sup>−

3</sup>, and between about 3×

10¹⁵ cm<sup>−

3</sup> and about 1×

10¹⁸ cm<sup>−

3</sup>, respectively.

19. The wafer of claim 13, wherein the wurtzite crystal structure is characterized to be substantially free of other crystal structures, the other crystal structures being less than about 1% in volume in reference to a volume of the substantially wurtzite crystal structure.

20. The wafer of claim 13, wherein the crystal is substantially free of cracks.

21. The wafer of claim 13, wherein the pattern is selected from two-dimensional hexagonal, square, rectangular, trapezoidal, triangular, and one-dimensional linear.

22. The wafer of claim 13, wherein the locally-approximately-linear arrays are oriented within about 5 degrees of a crystallographic plane selected from {10−

1 0}, {11−

2 0}, and {0 0 0±

1}, and a projection of the crystallographic plane on the large-area surface.

23. The wafer of claim 13, wherein the pattern is characterized by a pitch dimension between about 200 micrometers and about 5 millimeters.

24. The wafer of claim 13, wherein a linear concentration of the threading dislocations in the pattern is less than about 1×

10³ cm−

1 .

25. The wafer of claim 13, wherein the first large-area surface is characterized by a symmetric x-ray diffraction rocking-curve full width at half maximum value less than about 100 arcsec, an overall dislocation density below about 10⁵ cm⁻

2, and a dislocation density within the regions between the locally-approximately-linear arrays of threading dislocations is below about 10⁴ cm<sup>−

2</sup>.

26. The wafer of claim 13, wherein the stacking-fault concentration is below about 1 cm⁻

1.

27. The wafer of claim 13, further comprising a second large-area surface, wherein, the second large-area surface is substantially parallel to the first large-area surface;

and the crystal is characterized by a thickness between the first large-area surface and the second large-area surface between about 0.1 millimeter and about 1 millimeter, by a total thickness variation of less than about 10 micrometers, and by a macroscopic bow less than about 50 micrometers.

28. The wafer of claim 13, wherein the impurity concentration of at least one of Li, Na, K, F, CI, Br, and I is greater than about 10¹⁶ cm⁻

3.

29. The wafer of claim 13, wherein the impurity concentration of H is greater than about 10¹⁸ cm⁻

3.

30. The wafer of claim 13, wherein a ratio of the impurity concentration of H to an impurity concentration of O is between about 1.1 and about 100.

31. A wafer from a bulk crystal grown on a seed crystal derived from a group III metal nitride crystal made from a process comprising:

depositing at least one patterned mask layer on a substrate to form a patterned substrate, said mask layer comprising at least an inert layer comprising one or more of Au, Ag, Pt, Pd, Rh, Ru, Ir, Ni, Cr, V, Ti, or Ta, said inert layer being adhered to said substrate;

placing said patterned substrate within a sealable container along with a group III metal source, at least one mineralizer composition, and a nitrogen containing solvent; and

forming an ammonothermal group III metal nitride layer having one or more coalescence fronts on the patterned substrate by heating said sealable container;

wherein said wafer is a free-standing ammonothermal group III metal nitride crystal, wherein said crystal is a wurtzite crystal structure and comprises at least;

a group III metal selected from gallium, aluminum, indium, and a combination of any of the foregoing; and

nitrogen; and

a first large-area surface having a maximum dimension greater than about 10 millimeters;

wherein the first large-area surface is characterized by;

a symmetric x-ray rocking curve full width at half maximum less than about 200 arcsec,

an impurity concentration of H greater than about 10¹⁷ cm⁻

, and

an impurity concentration greater than about 10¹⁵ cm<sup>−

3</sup> of at least one of Li, Na, K, F, CI, Br, and I, as quantified by calibrated secondary ion mass spectrometry;

wherein the first large-area surface comprises regions in which the concentration of threading dislocations varies periodically by at least a factor of two in at least one direction, wherein a period of the variation is between about 5 micrometers and about 20 millimeters.

32. The wafer of claim 31, wherein the first large-area surface comprises regions in which the concentration of threading dislocations varies periodically by at least a factor of 10 in at least one direction, wherein the a period of the variation is between about between about 200 micrometers and about 5 millimeters.