Gallium nitride materials and methods associated with the same
View Patent ↗Semiconductor materials including a gallium nitride material region and methods associated with such structures are provided. The semiconductor structures include a strain-absorbing layer formed within the structure. The strain-absorbing layer may be formed between the substrate (e.g., a silicon substrate) and an overlying layer. It may be preferable for the strain-absorbing layer to be very thin, have an amorphous structure and be formed of a silicon nitride-based material. The strain-absorbing layer may reduce the number of misfit dislocations formed in the overlying layer (e.g., a nitride-based material layer) which limits formation of other types of defects in other overlying layers (e.g., gallium nitride material region), amongst other advantages. Thus, the presence of the strain-absorbing layer may improve the quality of the gallium nitride material region which can lead to improved device performance.
1. A semiconductor structure comprising:
a semiconductor material region;
a strain-absorbing layer wherein the entire strain-absorbing layer overlies the entire semiconductor material region, and wherein the entire strain-absorbing layer comprises a silicon nitride-based material and has an amorphous structure; and
a nitride-based material layer formed directly on the entire strain-absorbing layer, wherein the misfit dislocation density in the nitride-based material layer is less than about 10 10 defects/cm 2 .
2. The structure of claim 1 , wherein the semiconductor material region is a substrate.
3. The structure of claim 2 , wherein the substrate is substantially planar.
4. The structure of claim 2 , wherein the substrate is silicon.
5. The structure of claim 2 , wherein the substrate is silicon carbide.
6. The structure of claim 1 , wherein the misfit dislocation density is less than about 10 8 defects/cm 2 .
7. The structure of claim 1 , wherein the misfit dislocation density is less than about 10 5 defects/cm 2 .
8. The structure of claim 1 , wherein the misfit dislocation density is less than about 10 2 defects/cm 2 .
9. The structure of claim 1 , wherein the nitride-based material layer comprises an aluminum nitride-based material.
10. The structure of claim 1 , wherein the nitride-based material layer comprises a gallium nitride material.
11. The structure of claim 1 , wherein the nitride-based material layer is compositionally-graded.
12. The structure of claim 1 , further comprising a gallium nitride material region formed over the nitride-based material layer.
13. The structure of claim 12 , further comprising a compositionally-graded transition layer formed between the gallium nitride material region and the nitride-based material layer.
14. The structure of claim 12 , further comprising a source electrode, a gate electrode and a drain electrode formed on the gallium nitride material region.
15. The structure of claim 1 , wherein the substrate has a thickness of greater than about 125 micron.
16. The structure of claim 1 , wherein the strain-absorbing layer is substantially planar.
17. The structure of claim 1 , wherein the semiconductor material region is an underlying layer.
18. The structure of claim 1 , wherein the semiconductor material region comprises a gallium nitride material.
19. The structure of claim 1 , wherein the semiconductor material region comprises an aluminum nitride-based material.
20. The structure of claim 1 , wherein the semiconductor material region comprises a different material than the nitride-based material layer.
21. The structure of claim 1 , wherein the semiconductor material region has a different crystal structure than the nitride-based material layer.
22. The structure of claim 1 , wherein the nitride-based material layer is single-crystalline.
23. The structure of claim 1 , wherein the entire top surface of the strain-absorbing layer comprises SiN.
24. A semiconductor structure comprising:
a semiconductor material region;
a strain-absorbing layer wherein the entire strain-absorbing layer overlies the entire semiconductor material region, and wherein the entire strain-absorbing layer comprises a silicon nitride-based material and has a thickness of less than 100 Angstroms; and
a nitide-based material layer formed directly on the entire strain-absorbing layers, wherein the misfit dislocation density in the nitride-based material layer is less than about 10 10 defects/cm 2 .
25. The structure of claim 24 , wherein the silicon nitride-based material has an amorphous structure.
26. The structure of claim 24 , wherein the strain-absorbing layer has a thickness of greater than 10 Angstroms.
27. The structure of claim 24 , further comprising a gallium nitride material region formed over the nitride-based material layer.
28. The structure of claim 27 , further comprising a source electrode, a gate electrode and a drain electrode formed on the gallium nitride material region.
29. The structure of claim 24 , wherein the entire top surface of the strain-absorbing layer comprises Si X N Y .