Low micropipe 100 mm silicon carbide wafer
View Patent ↗A high quality single crystal wafer of SiC is disclosed having a diameter of at least about 100 mm and a micropipe density of less than about 25 cm −2 .
1. A high quality single crystal wafer of SiC having a diameter of at least about 100 mm and a micropipe density less than about 25 cm −2 .
2. A SiC crystal according to claim 1 wherein the micropipe density is less than about 20 cm −2 .
3. A SiC crystal according to claim 1 wherein the micropipe density is less than about 7 cm −2 .
4. A SiC crystal according to claim 1 wherein the crystal has a polytype selected from the group consisting of the 3C, 4H, 6H, 2H, and 15R polytypes.
5. A high quality semiconductor precursor wafer comprising:
a silicon carbide wafer having a diameter of at least about 100 mm;
said wafer having the 4H polytype; and
said wafer having a micropipe density on its surface of between 7 and 22 cm −2 .
6. A high quality semiconductor precursor wafer according to claim 5 wherein said surface micropipe density represents a count of the total micropipes on said surface divided by the surface area of said wafer.
7. A high quality semiconductor precursor wafer according to claim 6 wherein said surface micropipe density represents a count of the total micropipes on said surface following an etch that preferentially emphasizes micropipe defects.
8. A high quality semiconductor precursor wafer according to claim 7 wherein said surface micropipe density represents a count of the total micropipes on said surface following an etch of the surface in molten potassium hydroxide.
9. A high quality semiconductor precursor wafer comprising:
a silicon carbide wafer having a diameter of at least about 100 mm;
said wafer having the 4H polytype; and
said wafer having between about 545 and 1730 micropipes on its surface.
10. A high quality semiconductor precursor wafer according to claim 9 wherein said surface micropipes represent a count of the total micropipes on said surface.
11. A high quality semiconductor precursor wafer according to claim 10 wherein said surface micropipes represent a count of the total micropipes on said surface following an etch that preferentially emphasizes micropipe defects.
12. A high quality semiconductor precursor wafer according to claim 11 wherein said surface micropipes represent a count of the total micropipes on said surface following an etch of the surface in molten potassium hydroxide.
13. A high quality semiconductor precursor wafer comprising:
a silicon carbide wafer having a diameter of at least about 100 mm;
said wafer having the 4H polytype;
said wafer having a micropipe density on its surface of less than 25 cm −2 ; and
a Group III-nitride layer on said surface of said silicon carbide wafer.
14. A semiconductor precursor wafer according to claim 13 wherein said Group III-nitride layer is selected from the group consisting of GaN, A 1 GaN, AN, A 1 InGaN, InN, A 1 InN and mixtures thereof
15. A plurality of semiconductor device precursors comprising:
a silicon carbide wafer having a diameter of at least about 100 mm and micropipe density on the surface of less than 25 cm −2 ; and
a plurality of respective Group III-nitride epitaxial layers on some portions of said wafer.
16. A semiconductor wafer comprising:
a bulk single crystal silicon carbide substrate of at least about 100 mm and having a micropipe density of less than 25 cm −2 , said bulk single crystal having respective first and second surfaces opposite one another; and
a plurality of devices on said silicon carbide substrate, each said device comprising:
an epitaxial layer located on the substrate, said layer having a concentration of suitable dopant atoms for making the epitaxial layer a first conductivity type, and respective source, channel, and drain portions;
a metal oxide layer on said channel portion; and
a metal gate contact on said metal oxide layer for forming an active channel when a bias is applied to said metal gate contact.
17. A semiconductor wafer comprising:
a bulk single crystal silicon carbide substrate of at least about 100 mm and having a micropipe density of less than 25 cm −2 , said bulk single crystal having respective first and second surfaces opposite one another; and
a plurality of devices on said silicon carbide substrate, each said device comprising:
a conductive channel on said substrate;
a source and a drain on said conductive channel; and
a metal gate contact between said source and said drain on said conductive channel for forming an active channel when a bias is applied to the metal gate contact.
18. A semiconductor wafer comprising:
a bulk single crystal silicon carbide substrate of at least about 100 mm and having a micropipe density less than 25 cm −2 , said bulk single crystal having respective first and second surfaces opposite one another; and
a plurality of junction field-effect transistors positioned on said single crystal silicon carbide substrate.
19. A semiconductor wafer comprising:
a bulk single crystal silicon carbide substrate of at least about 100 mm and having a micropipe density less than 25 cm −2 , said bulk single crystal having respective first and second surfaces opposite one another; and
a plurality of hetero-field effect transistors positioned on said single crystal silicon carbide substrate.
20. A semiconductor wafer comprising:
a bulk single crystal silicon carbide substrate of at least about 100 mm and having a micropipe density less than 25 cm −2 , said bulk single crystal having respective first and second surfaces opposite one another; and
a plurality of diodes positioned on said single crystal silicon carbide substrate.
21. A high quality semiconductor precursor wafer according to claim 5 wherein said surface micropipe density is between 16 and 22 cm −2 .
22. A high quality semiconductor precursor wafer according to claim 9 wherein said wafer has between 1250 and 1730 micropipes on its surface.
23. A SiC crystal according to claim 1 wherein the micropipe density is between about 7 cm −2 and about 25 cm −2 .