Crystalline gallium nitride containing flourine
View Patent ↗A method for growing a crystalline composition, the first crystalline composition may include gallium and nitrogen. The crystalline composition may have an infrared absorption peak at about 3175 cm −1 , with an absorbance per unit thickness of greater than about 0.01 cm −1 . In one embodiment, the composition may have an amount of oxygen present in a concentration of less than about 3×10 18 per cubic centimeter, and may be free of two-dimensional planar boundary defects in a determined volume of the first crystalline composition.
1. A crystal comprising:
a single crystal of GaN having a wurtzite structure; and
fluorine having a concentration of at least 0.04 ppm.
2. The crystal of claim 1 , comprising at most 1 ppm fluorine.
3. The crystal according to claim 1 , having an infrared absorption peak at 3175 cm −1 , with an absorbance per unit thickness of greater than 0.01 cm −1 .
4. The crystal according to claim 1 , having an oxygen impurity level of less than 1×10 19 cm −3 .
5. The crystal according to claim 1 , having an oxygen impurity level of less than 3×10 18 cm −3 .
6. The crystal according to claim 1 , having a maximum dimension of at least 2 millimeters.
7. The crystal according to claim 1 , having a dislocation density below 10 6 cm −2 .
8. The crystal according to claim 7 , having a dislocation density below 10 4 cm −2 .
9. The crystal according to claim 1 , wherein the single crystal is free of tilt boundaries.
10. The crystal according to claim 1 , wherein the single crystal comprises one of n- type and p-type semiconductor and is optically transparent, with an optical absorption coefficient below 100 cm −1 at wavelengths between 700 and 465 nm.
11. The crystal of claim 10 , wherein the optical absorption coefficient is below 5 cm −1 at wavelengths between 465 and 700 nm.
12. The crystal according to claim 1 , further comprising a dopant comprising one or more of Be, C, Mg, Si, H, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Zr, Hf, or a rare earth metal.
13. The crystal according to claim 12 , wherein the dopant is present at a concentration in a range from 1×10 16 per cubic centimeter to 1×10 21 per cubic centimeter.
14. The crystal according to claim 1 , wherein the crystal is magnetic, is luminescent, or is both magnetic and luminescent.
15. The crystal according to claim 1 , wherein the crystal is characterized by a photoluminescence spectrum which peaks at a photon energy of in a range of from about 3.38 to about 3.41 eV at a temperature of 300 K.
16. A crystal made from a process comprising:
providing a nucleation center in a first region of a chamber;
providing a gallium nitride source material in a second region of the chamber;
providing a solvent in the chamber, the solvent comprising nitrogen;
providing a mineralizer in the chamber, the mineralizer comprising fluorine; and
heating the chamber and performing ammonothermal growth of GaN on the nucleation center under conditions to grow a single crystal of GaN having a wurtzite and having a concentration of fluorine of at least 0.04 ppm.
17. The crystal of claim 16 , wherein the mineralizer comprises at least one of hydrogen fluoride. ammonium fluoride, gallium trifluoride, or a compound produced by a chemical reaction between at least one of hydrogen fluoride, ammonium fluoride, gallium trifluoride, and one or more of ammonia (NH 3 ), gallium, or gallium nitride.
18. The crystal of claim 16 , wherein the process further comprises heating the chamber to a temperature of at least 550 degrees Celsius.
19. The crystal of claim 16 , wherein the process further comprises
generating and holding a first temperature distribution such that the solvent is supersaturated in the first region of the chamber and such that there is a first temperature gradient between the nucleation center and the gallium nitride source material such that gallium nitride crystalline composition grows on the nucleation center; and
generating a second temperature distribution in the chamber such that the solvent is supersaturated in the first region of the chamber and such that there is a second temperature gradient between the nucleation center and the gallium nitride source material such that gallium nitride crystalline composition grows on the nucleation center, wherein the second temperature gradient is larger in magnitude than the first temperature gradient.
20. The crystal of claim 16 , wherein the process further comprises:
generating and holding a first temperature distribution such that there is a first temperature gradient between the nucleation center and the gallium nitride source material; and
generating a second temperature distribution in the chamber such that the solvent is supersaturated in the first region of the chamber and such that there is a second temperature gradient between the nucleation center and the gallium nitride source material such that gallium nitride crystalline composition grows on the nucleation center, wherein the first temperature gradient is zero or opposite in sign from the second temperature gradient.