III-nitride wafer fabrication
View Patent ↗A method for fabrication of a III-nitride film over a silicon wafer that includes forming control joints to allow for overall stress relief in the III-nitride film during the growth thereof.
1. A method of fabricating a semiconductor wafer, comprising:
forming stress reduction trenches in a surface of a silicon substrate, said stress reduction trenches residing in regions designated to serve as dicing streets, said stress reduction trenches greater than one hundred times wider than deep, said dicing streets wider than said stress reduction trenches;
growing a III-nitride body over said surface of said silicon substrate, said III-nitride body filling said stress reduction trenches, wherein said III-nitride body extends continuously over a boundary between said surface and at least one of said stress reduction trenches, and wherein a stress relief crack is formed in said III-nitride body over at least one of said stress reduction trenches; and
dicing said semiconductor wafer into individual devices by cutting said semiconductor wafer along said dicing streets.
2. The method of claim 1 , wherein said stress reduction trenches cross one another.
3. The method of claim 1 , wherein said stress reduction trenches are between 10-25 mm apart.
4. The method of claim 1 , wherein said stress reduction trenches are about 100 angstroms deep.
5. The method of claim 1 , wherein said stress reduction trenches are more than 1 micron wide.
6. The method of claim 1 , wherein said stress reduction trenches form a grid.
7. The method of claim 1 , wherein said III-nitride body comprises AlN.
8. The method of claim 1 , wherein said III-nitride body is discontinuous over said stress reduction trenches.
9. A method of fabricating a semiconductor wafer, comprising:
forming stress reduction trenches in a surface of a silicon substrate, said stress reduction trenches residing in regions designated to serve as dicing streets, said stress reduction trenches greater than one hundred times wider than deep, said dicing streets wider than said stress reduction trenches;
growing a III-nitride body over said surface of said silicon substrate, wherein said III-nitride body extends continuously over a boundary between said surface and at least one of said stress reduction trenches;
filling said stress reduction trenches with said III-nitride body to form stress relief cracks in said III-nitride body over said stress reduction trenches; and
dicing said semiconductor wafer into individual devices by cutting said semiconductor wafer along said dicing streets.
10. The method of claim 9 , wherein said stress reduction trenches are about 100 angstroms deep.
11. The method of claim 9 , wherein said stress reduction trenches are between 10-25 mm apart.
12. The method of claim 6 , wherein said stress reduction trenches form a grid.
13. The method of claim 6 , wherein said III-nitride body comprises AlN.
14. A method of fabricating a semiconductor wafer, comprising:
forming stress reduction trenches in a surface of a silicon substrate, said stress reduction trenches residing in regions designated to serve as dicing streets, said stress reduction trenches greater than one hundred times wider than deep, said dicing streets wider than said stress reduction trenches;
growing a III-nitride body over said surface of said silicon substrate, said III-nitride body filling said stress reduction trenches, wherein said III-nitride body extends continuously over a boundary between said surface and at least one of said stress reduction trenches, and wherein a stress relief crack is formed in said III-nitride body over at least one of said stress reduction trenches;
forming a plurality of III-nitride devices over said III-nitride body; and
dicing said semiconductor wafer into individual III-nitride devices by cutting said semiconductor wafer along said dicing streets.
15. The method of claim 14 , wherein said stress reduction trenches are about 100 angstroms deep.
16. The method of claim 14 , wherein said stress reduction trenches are between 10-25 mm apart.
17. The method of claim 14 , wherein said stress reduction trenches form a grid.
18. The method of claim 14 , wherein said III-nitride body comprises AlN.
19. The method of claim 14 , wherein said III-nitride body is discontinuous over said stress reduction trenches.