III-nitride materials including low dislocation densities and methods associated with the same
View Patent ↗Semiconductor structures including one, or more, III-nitride material regions (e.g., gallium nitride material region) and methods associated with such structures are provided. The III-nitride material region(s) advantageously have a low dislocation density and, in particular, a low screw dislocation density. In some embodiments, the presence of screw dislocations in the III-nitride material region(s) may be essentially eliminated. The presence of a strain-absorbing layer underlying the III-nitride material region(s) and/or processing conditions can contribute to achieving the low screw dislocation densities. In some embodiments, the III-nitride material region(s) having low dislocation densities include a gallium nitride material region which functions as the active region of the device. The low screw dislocation densities of the active device region (e.g., gallium nitride material region) can lead to improved properties (e.g., electrical and optical) by increasing electron transport, limiting non-radiative recombination, and increasing compositional/growth uniformity, amongst other effects.
1. A semiconductor structure comprising:
a substrate;
a III-nitride material region formed on the substrate and having a screw dislocation density of less than 10 8 /cm 2 throughout the III-nitride material region;
a gallium nitride material region formed on the III-nitride region material and having a screw dislocation density of less than 10 8 /cm 2 throughout the gallium nitride material region,
wherein the gallium nitride material region has an area of greater than 1 mm×1 mm.
2. The structure of claim 1 , wherein the gallium nitride material region has a constant screw dislocation density throughout the gallium nitride material region.
3. The structure of claim 1 , wherein the substrate is planar.
4. The structure of claim 1 , wherein the gallium nitride material region is vertically-grown.
5. The structure of claim 1 , wherein the gallium nitride material region extends continuously across an underlying region.
6. The structure of claim 1 , wherein the screw dislocation density is less than about 10 4 /cm 2 throughout the gallium nitride material region.
7. The structure of claim 1 , wherein the screw dislocation density is zero throughout the gallium nitride material region.
8. The structure of claim 1 , wherein the edge dislocation density of the gallium nitride material region is greater than about 10 8 /cm 2 .
9. The structure of claim 1 , wherein the substrate is silicon.
10. the structure of claim 1 , further comprising a strain-absorbing layer, wherein the gallium nitride material region is formed on the strain-absorbing layer.
11. The structure of claim 10 , wherein the strain-absorbing layer comprising an amorphous silicon nitride-based material layer.
12. The structure of claim 11 , wherein the amorphous silicon nitride-based material layer has a thickness of less than 100 Angstroms.
13. A semiconductor structure comprising:
a III-nitride material region including an area having dimensions of at least 100 microns×100 microns and a screw dislocation density of less than 10 4 /cm 2 ; and
a strain-absorbing layer, wherein the III-nitride material region is formed on the strain-absorbing layer.
14. The structure of claim 13 , further comprising a second III-nitride material region including an area having dimensions of at least 100 microns×100 microns and a screw dislocation density of less than about 10 4 /cm 2 .
15. The structure of claim 13 , wherein the III-nitride material region includes an area having dimensions of at least 1 cm×1 cm and a screw dislocation density of less than 10 4 /cm 2 .
16. The structure of claim 13 , wherein the strain-absorbing layer comprises an amorphous silicon nitride-based material layer.
17. The structure of claim 13 , wherein the III-nitride material region is a gallium nitride material region.
18. The structure of claim 13 , wherein the strain-absorbing layer has a thickness of less than 100 Angstroms.
19. The structure of claim 13 , further comprising a substrate, wherein the strain-absorbing layer is formed on the substrate.
20. The structure of claim 19 , wherein the substrate is silicon.
21. The structure of claim 19 , wherein the strain-absorbing layer covers the an entire top surface of the substrate.
22. A semiconductor structure comprising:
a III-nitride material region having a screw dislocation density of zero and an edge dislocation density of greater than 10 8 /cm 2 , wherein the III-nitride material region has an area having dimensions of at least 100 micron×100 micron.
23. The structure of claim 22 , further comprising a substrate, wherein the III-nitride material region is formed on the substrate.
24. The structure of claim 22 , wherein the III-nitride material region is a gallium nitride material region.
25. The structure of claim 22 , wherein the III-nitride material region has an area having dimensions of at least 1 mm×1 mm.
26. The structure of claim 22 , further comprising a second III-nitride material region, wherein each III-nitride material region of the structure has screw dislocation density of less than 10 8 /cm 2 and an edge dislocation density of greater than 10 8 /cm 2 throughout the respective regions.
27. A semiconductor structure comprising:
a III-nitride material region having density of edge dislocation density and a screw dislocations, the density of edge dislocations being at least 10 4 times greater than the density of screw dislocations, wherein the III-nitride material region has an area having dimensions of at least 1 mm×1 mm.
28. The structure of claim 27 , further comprising a second III-nitride material region, wherein each III-nitride material region of the structure has density of edge dislocations at least 100 times greater than a density of screw dislocations throughout the respective regions.
29. The structure of claim 27 , wherein the screw dislocation density is less than 10 4 /cm 2 .
30. The structure of claim 27 , wherein the screw dislocation density is zero.
31. The structure of claim 27 , wherein the density of edge dislocations is at least 10 6 times greater than the density of screw dislocations.
32. The structure of claim 27 , wherein the III-nitride material region has an area having dimensions of at least 1 cm×1 cm.
33. The structure of claim 27 , wherein the III-nitride material region is a gallium nitride material region.
34. The structure of claim 33 , wherein the gallium nitride material region is formed on a second III-nitride material region, and the second III-nitride material region is formed on a substrate.
35. The structure of claim 27 , further comprising a substrate, wherein the III-nitride material region is formed on the substrate.
36. The structure of claim 35 , wherein the substrate is silicon.
37. A semiconductor structure comprising:
a substrate;
a silicon nitride-based material layer having a thickness of less than 100 Angstroms and covering an entire top surface of the substrate; and
a III-nitride material region formed over the silicon nitride-based material layer and having a screw dislocation density of less than about 10 8 /cm 2 .