Silicon material with controlled agglomerated point defects and oxygen clusters induced by the lateral surface
View Patent ↗The present invention relates to a single crystal silicon ingot or wafer wherein the lateral incorporation effect of intrinsic point defects has been manipulated such that the formation of agglomerated intrinsic point defects and/or oxygen precipitate clusters in a ring extending radially inward from about the lateral surface of the ingot segment is limited.
1. A single crystal silicon wafer having a diameter of at least 150 mm, a central axis, a front side and a back side that are generally perpendicular to the axis, a circumferential edge, and a radius (R) extending from the central axis to the circumferential edge of the wafer, the wafer comprises an annular ring extending radially inward from the circumferential edge of the wafer toward the central axis and extending axially from the front side to the back side of the wafer, said annular ring surrounding an axially symmetric core extending from the annular ring and toward the central axis and including the central axis, said ring (i) containing silicon lattice vacancies as the predominant intrinsic point defect, (ii) containing detectable agglomerated vacancy defects and/or oxygen clusters, said agglomerated vacancy defects having an average radius of less than 30 nm and greater than 5 nm and said oxygen clusters having an average radius of less than 10 nm and greater than 1 nm, and (iii) having an average radial width of at least 0.05 R and less than 0.7 R and said axially symmetric core comprising silicon lattice vacancies as the predominant intrinsic point defect, is free of detectable agglomerated intrinsic point defects, the region having a measurable radial width of less than 0.95 R.
2. The wafer of claim 1 , wherein said wafer has a diameter of 200 mm.
3. The wafer of claim 1 , wherein said wafer has a diameter of 300 mm.
4. The wafer of claim 1 , wherein said wafer has a diameter of greater than 300 mm.
5. The wafer of claim 1 , wherein said wafer comprises both detectable agglomerated vacancy defects and detectable oxygen clusters.
6. The wafer of claim 5 wherein said agglomerated vacancy defects have an average radial width of from 5 nm to 25 nm, and wherein said oxygen clusters have an average radial width of from 2 nm to 8 nm.
7. The wafer of claim 5 wherein said annular ring surrounds an axially symmetric region which is substantially free of micro-defects, or which comprises one or more additional rings or patterns of voids having an average radius of less than 30 nm, oxygen clusters having an average radius of less than 10 nm, and/or B-defects.
8. The wafer of claim 1 wherein said wafer comprises the detectable agglomerated vacancy defects at a concentration of less than 10 4 defects/cm 3 .
9. A single crystal silicon wafer having a diameter of at least 150 mm, a central axis, a front side and a back side that are generally perpendicular to the axis, a circumferential edge, and a radius (R) extending from the central axis to the circumferential edge of the wafer, the wafer comprises an annular ring extending radially inward from the circumferential edge of the wafer toward the central axis and extending axially from the front side to the back side of the wafer, said annular ring surrounding an axially symmetric core extending from the annular ring and toward the central axis and including the central axis, said ring (i) containing silicon lattice vacancies as the predominant intrinsic point defect, (ii) containing detectable agglomerated vacancy defects and/or oxygen clusters, said agglomerated vacancy defects having an average radius of less than 30 nm and greater than 5 nm and said oxygen clusters having an average radius of less than 10 nm and greater than 1 nm, and (iii) having an average radial width of at least 0.05 R and said axially symmetric core comprising silicon self-interstitials as the predominant intrinsic point defect, and optionally contains B-defects, the region having a measurable radial width of less than 0.95 R.
10. The wafer of claim 9 , wherein the axially symmetric core is substantially free of agglomerated intrinsic point defects.
11. The wafer of claim 9 , wherein said wafer has a diameter of 200 mm.
12. The wafer of claim 9 , wherein said wafer has a diameter of 300 mm.
13. The wafer of claim 9 wherein said wafer comprises the detectable agglomerated vacancy defects at a concentration of less than 10 4 defects/cm 3 .
14. The wafer of claim 9 , wherein said wafer has a diameter of greater than 300 mm.
15. A single crystal silicon wafer having a diameter of at least 150 mm, a central axis, a front side and a back side that are generally perpendicular to the axis, a circumferential edge, and a radius (R) extending from the central axis to the circumferential edge of the wafer, the wafer comprises a first annular ring extending radially inward from the circumferential edge of the wafer toward the central axis and extending axially from the front side to the back side of the wafer, an axially symmetric core, and a second annular ring that further surrounds the axially symmetric core, said axially symmetric core extending radially outward from the central axis toward the second annular ring, said first annular ring (i) containing silicon lattice vacancies as the predominant intrinsic point defect, (ii) containing detectable agglomerated vacancy defects and/or oxygen clusters, said agglomerated vacancy defects having an average radius of less than 30 nm and greater than 5 nm and said oxygen clusters having an average radius of less than 10 nm and greater than 1 nm, and (iii) having an average radial width of at least 0.05 R; said second annular ring being substantially free of agglomerated intrinsic point defects; and further wherein said axially symmetric core comprises silicon lattice vacancies as the predominant intrinsic point defect.
16. The wafer of claim 15 wherein said wafer comprises the detectable agglomerated vacancy defects at a concentration of less than 10 4 defects/cm 3 .
17. The wafer of claim 15 , wherein said wafer has a diameter of 200 mm.
18. The wafer of claim 15 , wherein said wafer has a diameter of 300 mm.
19. The wafer of claim 15 , wherein said wafer has a diameter of greater than 300 mm.