Composite substrates of conductive and insulating or semi-insulating group III-nitrides for group III-nitride devices
View Patent ↗Group III-Nitride semiconductor device structures and methods of fabricating Group III-Nitride structures are provided that include an electrically conductive Group III-Nitride substrate, such as a GaN substrate, and a semi-insulating or insulating Group III-Nitride epitaxial layer, such as a GaN epitaxial layer, on the electrically conductive Group III-Nitride substrate. The Group III-Nitride epitaxial layer has a lattice constant that is and a composition that may be substantially the same as a composition and a lattice constant of the Group III-Nitride substrate.
1. A Group III-Nitride High Electron Mobility Transistor (HEMT), comprising:
an electrically conductive Group III-Nitride substrate;
a semi-insulating or insulating Group III-Nitride epitaxial layer on the electrically conductive Group III-Nitride substrate, the Group III-Nitride epitaxial layer having a lattice constant that is substantially the same as a lattice constant of the Group III-Nitride substrate, wherein the Group III-Nitride epitaxial layer has an isolation voltage of at least about 50V; and a HEMT device structure on the semi-insulating or insulating GROUP III-Nitride epitaxial layer.
2. The HEMT of claim 1 , wherein the electrically conductive Group III-Nitride substrate and the semi-insulating or insulating Group III-Nitride epitaxial layer have substantially the same composition.
3. The HEMT of claim 2 , wherein the Group III-Nitride epitaxial layer has a thickness of at least about 5 μm.
4. The HEMT of claim 2 , wherein the Group III-Nitride epitaxial layer has a thickness of at least about 10 μm.
5. The HEMT of claim 2 , wherein the Group III-Nitride epitaxial layer is directly on the Group III-Nitride substrate.
6. The HEMT of claim 2 , wherein the Group III-Nitride epitaxial layer has a resistivity of at least 10 5 Ω-cm.
7. The HEMT of claim 2 , wherein the Group III-Nitride epitaxial layer has an isolation voltage of at least about 100V.
8. The HEMT of claim 2 , wherein the Group III-Nitride epitaxial layer is doped with a deep level transition metal dopant.
9. The HEMT of claim 8 , wherein the Group III-Nitride epitaxial layer is doped with Fe, Co, Mn, Cr, V and/or Ni.
10. The HEMT of claim 2 , wherein the concentration of the deep level transition metal dopant is at least about 1×10 16 cm −3 .
11. A GaN High Electron Mobility Transistor (HEMT), comprising:
an electrically conductive GaN substrate;
an insulating or semi-insulating GaN based epitaxial layer on the GaN substrate, the GaN based epitaxial layer having a composition and lattice constant that are substantially the same as a composition and lattice constant of the GaN substrate, wherein the GaN based epitaxial layer has an isolation voltage of at least about 50V; and a HEMT device structure on the insulating or semi-insulating GaN based epitaxial layer.
12. The HEMT of claim 11 , wherein the GaN based epitaxial layer has a thickness of at least about 5 μm.
13. The HEMT of claim 11 , wherein the GaN based epitaxial layer has a thickness of at about least 10 μm.
14. The HEMT of claim 11 , wherein the GaN based epitaxial layer is directly on the GaN substrate.
15. The HEMT of claim 11 , wherein the GaN based epitaxial layer has a resistivity of at least 10 5 Ω-cm.
16. The HEMT of claim 11 , wherein the GaN based epitaxial layer has an isolation voltage of at least about 100V.
17. The HEMT of claim 11 , wherein the GaN based epitaxial layer is doped with a deep level transition metal dopant.
18. The HEMT of claim 17 , wherein the GaN based epitaxial layer is doped with Fe, Co, Mn, Cr, V and/or Ni.
19. The HEMT of claim 17 , wherein the concentration of the deep level transition metal dopant is at least about 1×10 16 cm −3 .
20. A method of fabricating a Group III-Nitride High Electron Mobility Transistor (HEMT), comprising:
epitaxially forming a semi-insulating or insulating Group III-Nitride epitaxial layer on an electrically conductive Group III-Nitride substrate, the Group III-Nitride epitaxial layer having a lattice constant that is substantially the same as a lattice constant of the Group III-Nitride substrate, wherein the GaN based epitaxial layer has an isolation voltage from at least about 50V to at least about 100V; and forming a HEMT device structure on the semi-insulating or insulating Group III-Nitride epitaxial layer.
21. The method of claim 20 , wherein the electrically conductive Group III-Nitride substrate and the semi-insulating or insulating Group III-Nitride epitaxial layer have substantially the same composition.
22. The method of claim 21 , wherein the Group III-Nitride epitaxial layer has a thickness of at least about 5 μm.
23. The method of claim 21 , wherein the Group III-Nitride epitaxial layer has a thickness of at least about 10 μm.
24. The method of claim 21 , wherein the Group III-Nitride epitaxial layer is directly on the Group III-Nitride substrate.
25. The method of claim 21 , wherein the Group III-Nitride epitaxial layer has a resistivity of at least 10 5 Ω-cm.
26. The method of claim 21 , wherein the Group III-Nitride epitaxial layer has an isolation voltage of at least about 50V.
27. The method of claim 21 , wherein the Group III-Nitride epitaxial layer has an isolation voltage of at least about 100V.
28. The method of claim 21 , wherein the Group III-Nitride epitaxial layer is doped with a deep level transition metal dopant.
29. The method of claim 28 , wherein the Group III-Nitride epitaxial layer is doped with Fe, Co, Mn, Cr, V and/or Ni.
30. The method of claim 28 , wherein the concentration of the deep level transition metal dopant is at least about 1×10 16 cm −3 .
31. A method of fabricating a GaN High Electron Mobility Transistor (HEMT), comprising:
epitaxially forming an insulating or semi-insulating GaN based epitaxial layer on an electrically conductive GaN substrate, the GaN based epitaxial layer having a composition and lattice constant that are substantially the same as a composition and lattice constant of the GaN substrate, wherein the GaN based epitaxial layer has an isolation voltage from at least about 50V to at least about 100V; and forming a HEMT device structure on the insulating or semi-insulating GaN based epitaxial layer.
32. The method of claim 31 , wherein the GaN based epitaxial layer has a thickness of at least about 5 μm.
33. The method of claim 31 , wherein the GaN based epitaxial layer has a thickness of at least about 10 μm.
34. The method of claim 31 , wherein the GaN based epitaxial layer is directly on the GaN substrate.
35. The method of claim 31 , wherein the GaN based epitaxial layer has a resistivity of at least 10 5 Ω-cm.
36. The method of claim 31 , wherein the GaN based epitaxial layer has an isolation voltage of at least about 50V.
37. The method of claim 31 , wherein the GaN based epitaxial layer has an isolation voltage of at least about 100V.
38. The method of claim 31 , further comprising a Group III-Nitride high electron mobility transistor on the GaN based epitaxial layer.
39. The method of claim 31 , wherein the GaN based epitaxial layer is doped with a deep level transition metal dopant.
40. The method of claim 39 , wherein the GaN based epitaxial layer is doped with Fe, Co, Mn, Cr, V and/or Ni.
41. The method of claim 39 , wherein the concentration of the deep level transition metal dopant is at least about 1×10 16 cm −3 .