Transparent group III metal nitride and method of manufacture

• US 9,543,392 B1
• Filed: 09/12/2014
• Issued: 01/10/2017
• Est. Priority Date: 12/12/2008
• Status: Active Grant

• Current Assignee: SL Technology Incorporated (Reliv' International, Inc.)
• Original Assignee: Soraa, Inc.
• Inventors: Jiang, Wenkan, Ehrentraut, Dirk, D'Evelyn, Mark P.
• Primary Examiner(s): Sample, David
• Assistant Examiner(s): Flores, Jr., Donald M
• Application Number:
  US14/485,516
• Time in Patent Office: 851 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• 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 21/02389 Nitrides
• CPC Class Codes: H01L 21/02433 Crystal orientation
• 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 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/36 characterised by the concentration or distribution of impurities in the bulk material within semiconductor regions H01L29/06
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

Large-area, low-cost single crystal transparent gallium-containing nitride crystals useful as substrates for fabricating GaN devices for electronic and/or optoelectronic applications are disclosed. The gallium-containing nitride crystals are formed by controlling impurity concentrations during ammonothermal growth and processing to control the relative concentrations of point defect species.

Claims

1. A gallium-containing nitride crystal comprising:

a top surface having a crystallographic orientation within about 5 degrees of a plane selected from a (0001)+c-plane and a (000-1)−

c-plane;

a substantially wurtzite structure;

n-type electronic properties;

an impurity concentration greater than about 2×

10¹⁷ cm<sup>−

3</sup> of hydrogen;

an impurity concentration less than about 1×

10¹⁷ cm<sup>−

3</sup> of oxygen;

an H/O ratio of at least 10;

an impurity concentration greater than about 2×

10¹⁴ cm<sup>−

3</sup> of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl;

an optical absorption coefficient less than about 5 cm<sup>−

1</sup> at a wavelength of 400 nanometers;

an optical absorption coefficient less than about 4 cm<sup>−

1</sup> at a wavelength of 410 nanometers;

an optical absorption coefficient less than about 3 cm<sup>−

1</sup> at a wavelength of 415 nanometers; and

an optical absorption coefficient less than about 2 cm<sup>−

1</sup> at a wavelength of 450 nanometers;

wherein the gallium-containing nitride crystal is characterized by,

an absorbance per unit thickness of at least 0.01 cm<sup>−

1</sup> at wavenumbers of 3218 cm<sup>−

1</sup>, 3202 cm<sup>−

1</sup>, and 3188 cm<sup>−

1</sup>; and

no infrared absorption peaks at wavenumbers between about 3175 cm<sup>−

1</sup> and about 3000 cm<sup>−

1</sup> having an absorbance per unit thickness greater than 10% of the absorbance per unit thickness at 3218 cm<sup>−

1</sup>.

2. The gallium-containing nitride crystal of claim 1, characterized by a carrier concentration n between about 10¹⁶ cm⁻

3 and 10²⁰ cm<sup>−

3</sup> and a carrier mobility η

, in units of centimeters squared per volt-second, such that the logarithm to the base 10 of η

is greater than −

0.018557[log₁₀(n)]³+1.0671[log₁₀(n)]²−

20.599[log₁₀(n)]+135.49.

3. The gallium-containing nitride crystal of claim 1, further comprising an impurity concentration of at least one of silicon and germanium between about 1×

10¹⁷ cm<sup>−

3</sup> and about 3×

10¹⁸ cm<sup>−

3</sup>.

4. The gallium-containing nitride crystal of claim 1, wherein the carrier concentration is between about 3×

10¹⁷ cm<sup>−

3</sup> and about 3×

10¹⁸ cm<sup>−

3</sup>.

5. The gallium-containing nitride crystal of claim 1, wherein the top surface has a diameter greater than about 10 millimeters and the crystal has a thickness greater than about 100 micrometers.

6. The gallium-containing nitride crystal of claim 1, comprising an impurity concentration of at least one of F and Cl between about 2×

10¹⁴ cm<sup>−

3</sup> and about 5×

10¹⁷ cm<sup>−

3</sup>.

7. A device comprising the gallium-containing nitride crystal of claim 1.

8. A gallium-containing nitride crystal comprising:

a top surface having a crystallographic orientation within about 5 degrees of a plane selected from a (0001)+c-plane and a (000-1)−

c-plane;

a substantially wurtzite structure;

n-type electronic properties;

an impurity concentration greater than about 5×

10¹⁷ cm<sup>−

3</sup> of hydrogen;

an impurity concentration between about 2×

10¹⁷ cm<sup>−

3</sup> and about 4×

10¹⁸ cm<sup>−

3</sup> of oxygen;

an H/O ratio of at least 0.3;

an impurity concentration greater than about 1×

10¹⁶ cm<sup>−

3</sup> of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl;

an optical absorption coefficient less than about 8 cm<sup>−

1</sup> at a wavelength of 400 nanometers;

an optical absorption coefficient less than about 6 cm<sup>−

1</sup> at a wavelength of 410 nanometers;

an optical absorption coefficient less than about 5.5 cm<sup>−

1</sup> at a wavelength of 415 nanometers;

an optical absorption coefficient less than about 4 cm<sup>−

1</sup> at a wavelength of 450 nanometers;

an absorbance per unit thickness of at least 0.01 cm<sup>−

1</sup> at wavenumbers of approximately 3175 cm<sup>−

1</sup>, 3164 cm<sup>−

1</sup>, and 3150 cm<sup>−

1</sup>;

no infrared absorption peaks at wavenumbers between about 3200 cm<sup>−

1</sup> and about 3400 cm<sup>−

1</sup> or between about 3075 cm<sup>−

1</sup> and about 3125 cm<sup>−

1</sup> having an absorbance per unit thickness greater than 10% of the absorbance per unit thickness at 3175 cm<sup>−

1</sup>.

9. The gallium-containing nitride crystal of claim 8, characterized by a carrier concentration n between about 10¹⁶ cm⁻

3 and 10²⁰ cm<sup>−

3</sup> and a carrier mobility η

, in units of centimeters squared per volt-second, such that the logarithm to the base 10 of η

is greater than −

0.018557[log₁₀(n)]³+1.0671[log₁₀(n)]²−

20.599[log₁₀(n)]+135.49.

10. The gallium-containing nitride crystal of claim 8, further comprising an impurity concentration of at least one of silicon and germanium between about 1×

10¹⁷ cm<sup>−

3</sup> and about 3×

10¹⁸ cm<sup>−

3</sup>.

11. The gallium-containing nitride crystal of claim 8, wherein the carrier concentration is between about 3×

10¹⁷ cm<sup>−

3</sup> and about 3×

10¹⁸ cm<sup>−

3</sup>.

12. The gallium-containing nitride crystal of claim 8, wherein the top surface has a diameter greater than about 10 millimeters and the crystal has a thickness greater than about 100 micrometers.

13. The gallium-containing nitride crystal of claim 8, characterized by,

an optical absorption coefficient less than about 4 cm⁻

1 at a wavelength of 400 nanometers;

an optical absorption coefficient less than about 3 cm<sup>−

1</sup> at a wavelength of 410 nanometers;

an optical absorption coefficient less than about 2.5 cm<sup>−

1</sup> at a wavelength of 415 nanometers; and

an optical absorption coefficient less than about 1.5 cm<sup>−

1</sup> at a wavelength of 450 nanometers.

14. The gallium-containing nitride crystal of claim 8, characterized by,

an optical absorption coefficient less than about 3 cm⁻

1 at a wavelength of 400 nanometers;

an optical absorption coefficient less than about 2.2 cm<sup>−

1</sup> at a wavelength of 410 nanometers;

an optical absorption coefficient less than about 2.0 cm<sup>−

1</sup> at a wavelength of 415 nanometers; and

an optical absorption coefficient less than about 1.0 cm<sup>−

1</sup> at a wavelength of 450 nanometers.

15. A device comprising the gallium-containing nitride crystal of claim 8.

16. A gallium-containing nitride crystal comprising:

a top surface having a crystallographic orientation within about 5 degrees of a {1 0-1 0} m-plane;

a substantially wurtzite structure;

n-type electronic properties;

an impurity concentration greater than about 3×

10¹⁸ cm<sup>−

3</sup> of hydrogen;

an impurity concentration between about 5×

10¹⁷ cm<sup>−

3</sup> and about 3×

10¹⁹ cm<sup>−

3</sup> of oxygen;

an H/O ratio of at least 1.1;

an impurity concentration greater than about 1×

10¹⁶ cm<sup>−

3</sup> of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl;

an optical absorption coefficient less than about 8 cm<sup>−

1</sup> at a wavelength of 400 nanometers;

an optical absorption coefficient less than about 6 cm<sup>−

1</sup> at a wavelength of 410 nanometers;

an optical absorption coefficient less than about 5.5 cm<sup>−

1</sup> at a wavelength of 415 nanometers;

an optical absorption coefficient less than about 4 cm<sup>−

1</sup> at a wavelength of 450 nanometers;

an absorbance per unit thickness of at least 0.01 cm<sup>−

1</sup> at 3188 cm<sup>−

1</sup>, 3175 cm<sup>−

1</sup>, 3164 cm<sup>−

1</sup>, and 3150 cm<sup>−

1</sup>; and

no infrared absorption peaks at wavenumbers between about 3125 cm<sup>−

1</sup> and about 3000 cm<sup>−

1</sup>, having an absorbance per unit thickness greater than 10% of the absorbance per unit thickness at 3188 cm<sup>−

1</sup>.

17. The gallium-containing nitride crystal of claim 16, characterized by a carrier concentration n between about 10¹⁶ cm⁻

3 and 10²⁰ cm<sup>−

3</sup> and a carrier mobility η

, in units of centimeters squared per volt-second, such that the logarithm to the base 10 of η

is greater than −

0.018557[log₁₀(n)]³+1.0671[log₁₀(n)]²−

20.599[log₁₀(n)]+135.49.

18. The gallium-containing nitride crystal of claim 16, wherein the absorbance per unit thickness at 3232 cm⁻

1 is at least 0.01 cm<sup>−

1</sup>.

19. The gallium-containing nitride crystal of claim 16, further comprising an impurity concentration of at least one of silicon and germanium between about 1×

10¹⁷ cm<sup>−

3</sup> and about 3×

10¹⁸ cm<sup>−

3</sup>.

20. The gallium-containing nitride crystal of claim 16, wherein the carrier concentration is between about 3×

10¹⁷ cm<sup>−

3</sup> and about 3×

10¹⁸ cm<sup>−

3</sup>.

21. The gallium-containing nitride crystal of claim 16, wherein the top surface has a diameter greater than about 10 millimeters and the crystal has a thickness greater than about 100 micrometers.

22. A device comprising the gallium-containing nitride crystal of claim 16.