Crystalline composition, wafer, device, and associated method
View Patent ↗A crystalline composition is provided that includes gallium and nitrogen. The crystalline 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 crystalline composition. The volume may have at least one dimension that is about 2.75 millimeters or greater, and the volume may have a one-dimensional linear defect dislocation density of less than about 10,000 per square centimeter.
1. A crystalline composition comprising gallium and nitrogen having a volume defined by dimensions x, y, and w, wherein x and y defining a plane perpendicular to thickness w, and the crystalline composition has an amount of oxygen present in a concentration of less than about 3×10 18 per cubic centimeter, and is free of two-dimensional planar boundary defects in the volume,
wherein at least one dimension x or y is 2.75 millimeters or greater, and the volume has a one-dimensional linear defect dislocation density of less than about 10,000 per square centimeter.
2. The crystalline composition as defined in claim 1 , wherein the crystalline composition is free of magnesium and is optically transparent, having an optical absorption coefficient below 100 cm −1 at wavelengths between 465 nm and 700 nm.
3. The crystalline composition as defined in claim 1 , wherein the two-dimensional planar boundary defect is a grain boundary.
4. The crystalline composition as defined in claim 3 , wherein:
the dislocation density less than 1000 per square centimeter, or
the grain has at least one dimension x or y that is greater than about 3 millimeters.
5. The crystalline composition as defined in claim 4 , wherein:
the dislocation density is less than 100 per square centimeter, or
the grain has at least one dimension x or y that is greater than about 5 millimeters.
6. The crystalline composition as defined in claim 1 , wherein the thickness w is greater than about 100 micrometers.
7. The crystalline composition as defined in claim 1 , wherein the crystalline composition has an oxygen concentration of less than about 5×10 17 per cubic centimeter.
8. The crystalline composition as defined in claim 1 , wherein the x-ray rocking curve full width at half maximum of the (0002) reflection in the ω direction of the crystalline composition in the volume is 30 arc-sec or less.
9. The crystalline composition as defined in claim 1 , wherein the crystalline composition has an electrical property such that the crystalline composition is capable of functioning as a p-type semiconductor at about room temperature.
10. The crystalline composition as defined in claim 9 , wherein the crystalline composition is a p-type semiconductor at a temperature in a range of less than about 250 Kelvin.
11. The crystalline composition as defined in claim 1 , wherein the crystalline composition is an opaque crystalline composition and is black in color.
12. The crystalline composition as defined in claim 11 , wherein a ratio of intensity of near-band-edge photoluminescence from the black crystalline composition to that of a crystalline composition that is both transparent and undoped is less than about 0.1 percent.
13. The crystalline composition as defined in claim 1 , wherein the crystalline composition has a photoluminescence spectrum peaking at a photon energy of in a range of from about 3.38 eV to about 3.41 eV at a crystalline composition temperature of about 300 K.
14. The crystalline composition as defined in claim 1 , wherein the crystalline composition is an n-type semiconductor.
15. The crystalline composition as defined in 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.
16. The crystalline composition as defined in claim 15 , wherein the dopant is present in a concentration in a range of from about 1×10 16 per cubic centimeter to about 1×10 21 per cubic centimeter.
17. The crystalline composition as defined in claim 1 , wherein the crystalline composition is a single crystal.
18. The crystalline composition as defined in claim 1 , wherein the crystalline composition is magnetic, is luminescent, or is both magnetic and luminescent.
19. The crystalline composition as defined in claim 1 , wherein the crystalline composition has an infrared absorption peak at about 3175 cm −1 , with an absorbance per unit thickness of greater than about 0.01 per centimeter.
20. The crystalline composition as defined in claim 1 , wherein the crystalline composition comprises more than about 0.04 ppm halide.
21. The crystalline composition as defined in claim 1 , wherein the crystalline composition comprises a detectable amount, but less than about 5 mole percent, of each of aluminum, arsenic, boron, indium, or phosphorus; or less than about 5 mole percent of a combination of two or more thereof.
22. A wafer comprising the crystalline composition as defined in claim 1 .
23. The wafer as defined in claim 22 , wherein the wafer has a crystallographic orientation that is within about 10° of one of an (0001) orientation, an (000 1 ) orientation, an (10 1 0) orientation, an (11 2 0) orientation, or an (10 1 1) orientation.
24. The wafer as defined in claim 23 , wherein the crystallographic orientation is within about 50 of one of the (0001) orientation, the (000 1 ) orientation, the (10 1 0) orientation, the (11 2 0) orientation, or the (10 1 1) orientation.
25. The wafer as defined in claim 22 , wherein the wafer has a rounded edge defining an arc.
26. The wafer as defined in claim 25 , wherein the radius of curvature of the top edge of the wafer is between 10 micrometers and 50% of the thickness of the wafer, the angle between the inside edge of the rounded portion and the top surface of the wafer is less than 30 degrees, and the radius of curvature of the bottom edge of the wafer is greater than the radius of curvature of the top edge of the wafer and forms an angle with the bottom surface of the wafer that is less than 30 degrees.
27. The wafer as defined in claim 22 , wherein the wafer has at least one chamfered edge.
28. The wafer as defined in claim 27 , wherein the at least one chamfer has a depth that is in a range of from about 10 micrometers to about 20 percent of a thickness dimension of the wafer, and a width that is in a range of from about 1 time to about 5 times the depth.
29. The wafer as defined in claim 27 , wherein the wafer has a surface with a surface roughness that is less than 1 nanometer RMS over a lateral area of at least 10×10 micrometers squared.
30. A semiconductor structure, comprising the wafer as defined in claim 22 .
31. The semiconductor structure as defined in claim 30 , further comprising a homoepitaxial layer disposed on the crystalline composition, the homoepitaxial layer comprising a Al x In y Ga 1-x-y N layer, where 0≦x≦1, 0≦y≦1 and 0≦x+y≦1.
32. The semiconductor structure as defined in claim 30 , wherein the semiconductor structure forms a portion of one or more of a diode, detector, transducer, transistor, rectifier, thyristor, emitter, or switch.
33. The semiconductor structure as defined in claim 32 , wherein the semiconductor structure forms a portion of a field effect transistor.
34. The semiconductor structure as defined in claim 32 , wherein the semiconductor structure forms a portion of a light emitting diode, a laser diode, a photodetector, an avalanche photodiode, a p-i-n diode, a metal-semiconductor-metal diode, a Schottky rectifier, a 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, or a quantum dot infrared photodetector.
35. A crystalline composition comprising gallium and nitrogen and having a volume defined by dimensions x, y, and w, wherein x and y defining a plane perpendicular to thickness w, and at least a portion of the volume has a one-dimensional linear defect dislocation density of less than about 10,000 per square centimeter, and wherein at least one dimension x or y is greater than 2.75 millimeters, and the crystalline composition is free of tilt boundaries and of grain boundaries in the volume.
36. The crystalline composition as defined in claim 35 , wherein the volume has a surface and the apparent one-dimensional linear defect dislocation density on the surface is less than 1000 per square centimeter.
37. A crystalline composition comprising gallium and nitrogen,
the crystalline composition being a wafer cut from a boule or an ingot, and having a macroscopic crystallographic orientation at a surface that is constant to within less than 1 degree over a distance of 1 centimeter.