Low basal plane dislocation bulk grown SiC wafers
View Patent ↗A high quality single crystal wafer of SiC is disclosed. The wafer has a diameter of at least about 3 inches (75 mm) and at least one continuous square inch (6.25 cm 2 ) of surface area that has a basal plane dislocation volume density of less than about 500 cm −2 for a 4 degree off-axis wafer.
1. A high quality single crystal wafer of SiC having a diameter of at least about 3 inches and at least one continuous square inch of surface area that has a basal plane dislocation density less than about 500 cm −2 .
2. A SiC wafer according to claim 1 wherein said at least one continuous square inch of surface area has a basal plane dislocation density that is less than about 100 cm −2 .
3. A SiC wafer according to claim 1 wherein said at least one continuous square inch of surface area has a basal plane dislocation density that is less than about 50 cm −2 .
4. A SiC wafer 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 wafer comprising:
a silicon carbide wafer having a diameter of at least about 3 inches;
said wafer having the 4H polytype; and
said wafer having at least one continuous square inch of surface area that has a basal plane dislocation density on its surface of between about 50 and about 500 cm −2 .
6. A high quality semiconductor wafer comprising:
a silicon carbide wafer having a diameter of at least about 3 inches; and
said wafer having at least one continuous square inch of surface area having between about 2,000 and 20,000 basal plane dislocations.
7. A high quality semiconductor wafer comprising:
a silicon carbide wafer having a diameter of at least about 3 inches;
said wafer having at least one continuous square inch of surface area having a basal plane dislocation density of less than about 500 cm −2 ; and
a Group III-nitride epitaxial layer on said surface of said silicon carbide wafer.
8. A semiconductor wafer according to claim 7 wherein said Group III-nitride layer is selected from the group consisting of GaN, AlGaN, AlN, AlInGaN, InN, AlInN and mixtures thereof.
9. A plurality of semiconductor device precursors comprising:
a silicon carbide wafer having a diameter of at least about 3 inches and having at least one continuous square inch of surface area with a basal plane dislocation density of less than about 500 cm −2 ; and
a plurality of respective Group III-nitride epitaxial layers on some portions of said wafer.
10. A semiconductor wafer comprising:
a bulk single crystal silicon carbide substrate of at least about 3 inches and having at least one continuous square inch of surface area with a basal plane dislocation density of less than about 500 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
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.
11. A semiconductor wafer comprising:
a bulk single crystal silicon carbide substrate of at least about 3 inches and having at least one continuous square inch of surface area with a basal plane dislocation density of less than 500 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.
12. A semiconductor wafer comprising:
a bulk single crystal silicon carbide substrate of at least about 3 inches and having at least one continuous square inch of surface area with a basal plane dislocation density less than 500 cm −2 , said bulk single crystal having respective first and second surfaces opposite one another.
13. A semiconductor wafer according to claim 12 further comprising a plurality of junction field-effect transistors positioned on said first surface of said single crystal silicon carbide substrate.
14. A semiconductor wafer according to claim 12 further comprising a plurality of hetero-field effect transistors positioned on said first surface of said single crystal silicon carbide substrate.
15. A semiconductor wafer according to claim 12 further comprising a plurality of diodes positioned on said first surface of said single crystal silicon carbide substrate.