Large dimension silicon carbide single crystalline materials with reduced crystallographic stress
Silicon carbide (SiC) materials including SiC wafers and SiC boules and related methods are disclosed that provide large dimension SiC wafers with reduced crystallographic stress. Growth conditions for SiC materials include maintaining a generally convex growth surface of SiC crystals, adjusting differences in front-side to back-side thermal profiles of growing SiC crystals, supplying sufficient source flux to allow commercially viable growth rates for SiC crystals, and reducing the inclusion of contaminants or non-SiC particles in SiC source materials and corresponding SiC crystals. By forming larger dimension SiC crystals that exhibit lower crystallographic stress, overall dislocation densities that are associated with missing or additional planes of atoms may be reduced, thereby improving crystal quality and usable SiC crystal growth heights.
1. A silicon carbide (SiC) wafer comprising a dimension of at least 195 millimeters (mm) and a total line density of basal plane dislocations that are aligned within 5 degrees of a {1 1 00} family of crystal planes of less than 1000 centimeters per centimeter cubed (cm/cm 3 ) for a first area bounded by a radius from a center of the SiC wafer, the radius comprising at least 50% of a wafer radius of the SiC wafer.
2. The SiC wafer of claim 1 , wherein the dimension is in a range from 195 mm to 205 mm.
3. The SiC wafer of claim 1 , wherein the dimension is in a range from 195 mm to 455 mm.
4. The SiC wafer of claim 1 , wherein the total line density of basal plane dislocations that are aligned within 5 degrees of the {1 1 00} family of crystal planes in a range from 0 cm/cm 3 to less than 1000 cm/cm 3 .
5. The SiC wafer of claim 1 , wherein the total line density of basal plane dislocations that are aligned within 5 degrees of the {1 1 00} family of crystal planes in the first area is less than 200 cm/cm 3 .
6. The SiC wafer of claim 1 , wherein the total line density of basal plane dislocations that are aligned within 5 degrees of the {1 1 00} family of crystal planes in the first area is less than 100 cm/cm 3 .
7. The SiC wafer of claim 1 , wherein the radius that bounds the first area comprises at least 90% of the wafer radius of the SiC wafer.
8. A SiC wafer comprising:
a dimension of at least 195 millimeters (mm) and a total line density of basal plane dislocations that are aligned within 5 degrees of a {1 1 00} family of crystal planes of less than 1000 centimeters per centimeter cubed (cm/cm 3 ) for a first area bounded by a radius from a center of the SiC wafer, the radius comprising at least 50% of a wafer radius of the SiC wafer; and
a second area that is defined between the first area and a perimeter edge of the SiC wafer, wherein the second area comprises a total line density of basal plane dislocations that are aligned within 5 degrees of the {1 1 00} family of crystal planes that is higher than the first area.
9. The SiC wafer of claim 8 , wherein the total line density of basal plane dislocations that are aligned within 5 degrees of the { 1 1 00 } family of crystal planes in the second area is less than 1000 cm/cm 3 .
10. The SiC wafer of claim 1 , wherein the SiC wafer comprises at least one of a 4H—SiC wafer, a semi-insulating SiC wafer, and a n-type SiC wafer.