Semi-insulating group III metal nitride and method of manufacture
View Patent ↗A large-area, high-purity, low-cost single crystal semi-insulating gallium nitride that is useful as substrates for fabricating GaN devices for electronic and/or optoelectronic applications is provided. The gallium nitride is formed by doping gallium nitride material during ammonothermal growth with a deep acceptor dopant species, e.g., Mn, Fe, Co, Ni, Cu, etc., to compensate donor species in the gallium nitride, and impart semi-insulating character to the gallium nitride.
1. A bulk gallium-containing nitride crystal comprising:
a length greater than about 5 millimeters;
a wurtzite crystal structure;
a concentration of oxygen from about 10 10 atoms per cubic centimeter to about 10 17 atoms per cubic centimeter;
an impurity concentration greater than about 10 15 cm −3 of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl;
a compensatory dopant selected from V, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, and a combination of any of the foregoing, wherein the concentration of the compensatory dopant is between about 10 14 cm −3 and about 10 16 cm −3 ;
an optical absorption coefficient less than about 10 cm −1 at wavelengths between about 395 nm and about 460 nm; and
an electrical resistivity at room temperature greater than about 10 7 ohm-centimeter.
2. The gallium-containing nitride crystal of claim 1 , comprising an impurity concentration of oxygen less than about 10 16 cm −3 .
3. The gallium-containing nitride crystal of claim 1 , comprising an impurity concentration of oxygen less than about 10 15 cm −3 .
4. The gallium-containing nitride crystal of claim 1 , wherein the concentration of the compensatory dopants is less than about 10 16 cm −3 .
5. The gallium-containing nitride crystal of claim 1 , wherein the optical absorption coefficient at wavelengths between about 395 nm and about 460 nm is less than about 2 cm −1 .
6. The gallium-containing nitride crystal of claim 1 , wherein the optical absorption coefficient at wavelengths between about 395 nm and about 460 nm is less than about 0.2 cm −1 .
7. The gallium-containing nitride crystal of claim 1 , wherein the gallium-containing nitride crystal has a thickness of greater than about 1 millimeter.
8. The gallium-containing nitride crystal of claim 7 , wherein the length is greater than about 20 millimeters.
9. The gallium-containing nitride crystal of claim 1 , wherein the length is greater than about 100 millimeters.
10. The gallium-containing nitride crystal of claim 1 , wherein the crystal is characterized by a crystallographic radius curvature of greater than 100 meters.
11. The gallium-containing nitride crystal of claim 1 , comprising a large-area surface characterized by-a root-mean-square surface roughness of 1 nanometer and less.
12. The gallium-containing nitride crystal of claim 11 , wherein the large-area surface has a crystallographic orientation within about 5 degrees of (0 0 0 ±1) c-plane.
13. The gallium-containing nitride crystal of claim 11 , wherein the large-area surface has a crystallographic orientation within about 5 degrees of (1 0 −1 0) m-plane.
14. A device comprising the gallium-containing nitride crystal of claim 1 , wherein the device is selected from a light emitting diode, a laser diode, a photodetector, an avalanche photodiode, a transistor, a rectifier, a thyristor; a transistor, a rectifier, a Schottky rectifier, a thyristor, a p-i-n diode, a metal-semiconductor-metal diode, high-electron mobility transistor, a metal semiconductor field effect transistor, a metal oxide field effect transistor, a power metal oxide semiconductor field effect transistor, a power metal insulator semiconductor field effect transistor, a bipolar junction transistor, a metal insulator field effect transistor, a heterojunction bipolar transistor, a power insulated gate bipolar transistor, a power vertical junction field effect transistor, a cascode switch, an inner sub-band emitter, a quantum well infrared photodetector, a quantum dot infrared photodetector, a solar cell, and a diode for photoelectrochemical water splitting and hydrogen generation.
15. The gallium-containing nitride crystal of claim 1 , wherein the electrical resistivity at room temperature is greater than about 10 9 ohm-centimeter.
16. The gallium-containing nitride crystal of claim 1 , wherein the electrical resistivity at room temperature is greater than about 10 11 ohm-centimeter.
17. The gallium-containing nitride crystal of claim 1 , comprising an oxygen content as a substitutional impurity less than about 10 parts per million.
18. The gallium-containing nitride crystal of claim 1 , comprising an oxygen content as a substitutional impurity less than about 1 parts per million.
19. The gallium-containing nitride crystal of claim 1 , wherein the gallium-containing nitride crystal is semi-insulating.
20. The gallium-containing nitride crystal of claim 1 , wherein the room temperature resistivity is from 10 7 ohm-centimeters to 10 12 ohm-centimeters.
21. The gallium-containing nitride crystal of claim 1 , wherein the crystal is free-standing.
22. A bulk gallium-containing nitride crystal, comprising:
a wurtzite structure;
an impurity concentration greater than about 10 15 cm −3 of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl;
a concentration of oxygen from about 10 10 atoms per cubic centimeter to about 10 17 atoms per cubic centimeter;
a compensatory dopant selected from V, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, and a combination of any of the foregoing, wherein the concentration of the compensatory dopant is between about 10 14 cm −3 and about 10 16 cm −3 ;
an optical absorption coefficient less than about 2 cm −1 at wavelengths between about 395 nm and about 460 nm; and
an electrical resistivity at room temperature greater than about 10 7 ohm-centimeter.