Method of producing periodic table group 13 metal nitride semiconductor crystal and periodic table group 13 metal nitride semiconductor crystal produced by this production method
For a Periodic Table Group 13 metal nitride semiconductor crystal obtained by epitaxial growth on the main surface of a base substrate that has a nonpolar plane and/or a semipolar plane as its main surface, an object of the present invention is to provide a high-quality semiconductor crystal that has a low absorption coefficient, is favorable for a device, and is controlled dopant concentration in the crystal, and to provide a production method that can produce the semiconductor crystal. A high-quality Periodic Table Group 13 metal nitride semiconductor crystal that has a precisely controlled dopant concentration within the crystal and a low absorption coefficient and that is thus favorable for a device, can be provided by inhibiting oxygen doping caused by impurity oxygen and having the Si concentration higher than the O concentration.
1. A gallium nitride crystal grown in a direction orthogonal to a nonpolar or semipolar plane thereof,
wherein, in a cryogenic PL spectrum of the crystal, measured at temperature of 20 K or below, an I 2 /I 1 ratio is not greater than 0.1, where I 1 is a peak intensity of a band edge emission and I 2 is an intensity of an emission at 3.41 eV.
2. The gallium nitride crystal according to claim 1 , wherein a Si concentration within the gallium nitride crystal is higher than an O concentration within the gallium nitride crystal.
3. The gallium nitride crystal according to claim 1 , wherein the I 2 /I 1 ratio is not greater than 0.05.
4. The gallium nitride crystal according to claim 1 , wherein the I 2 /I 1 ratio is not greater than 0.01.
5. The gallium nitride crystal according to claim 1 , having a dislocation extending in a direction parallel to a growth direction of the gallium nitride crystal.
6. The gallium nitride crystal according to claim 5 , wherein a density of the dislocation is not greater than 1.0×10 8 cm −2 .
7. The gallium nitride crystal according to claim 1 , wherein a Si concentration within the gallium nitride crystal is at least 1×10 17 cm −3 .
8. The gallium nitride crystal according to claim 1 , wherein an O concentration within the gallium nitride crystal is not greater than 3×10 18 cm −3 .
9. The gallium nitride crystal according to claim 1 , wherein a Na concentration within the gallium nitride crystal is not greater than 1×10 17 cm −3 .
10. The gallium nitride crystal according to claim 1 , wherein a growing direction of the gallium nitride crystal is orthogonal to the nonpolar plane thereof.
11. The gallium nitride crystal according to claim 10 , comprising a gallium nitride crystal grown on a base substrate formed of gallium nitride for which a main surface of the base substrate is a nonpolar plane.
12. The gallium nitride crystal according to claim 1 , wherein a growing direction of the gallium nitride crystal is orthogonal to the semipolar plane thereof.
13. The gallium nitride crystal according to claim 12 , comprising a gallium nitride crystal grown on a base substrate formed of gallium nitride for which a main surface of the base substrate is a semipolar plane.
14. The gallium nitride crystal according to claim 1 , wherein a size of the crystal along a growth direction thereof is at least 10 μm.
15. A substrate, comprising the gallium nitride crystal according to claim 1 .
16. A method of manufacturing a semiconductor device, the method comprising
manufacturing the semiconductor device with the substrate according to claim 15 .
17. The method according to claim 16 , wherein the semiconductor device comprises a light emitting element.
18. The method according to claim 16 , wherein the semiconductor device comprises an electronic device.