Nitrogen doped and vacancy dominated silicon ingot and thermally treated wafer formed therefrom having radially uniformly distributed oxygen precipitation density and size
Nitrogen-doped CZ silicon crystal ingots and wafers sliced therefrom are disclosed that provide for post epitaxial thermally treated wafers having oxygen precipitate density and size that are substantially uniformly distributed radially and exhibit the lack of a significant edge effect. Methods for producing such CZ silicon crystal ingots are also provided by controlling the pull rate from molten silicon, the temperature gradient and the nitrogen concentration. Methods for simulating the radial bulk micro defect size distribution, radial bulk micro defect density distribution and oxygen precipitation density distribution of post epitaxial thermally treated wafers sliced from nitrogen-doped CZ silicon crystals are also provided.
1. A nitrogen-doped single crystal silicon wafer having a front surface and a back surface, and a circumferential edge joining the front surface and the back surface, wherein:
(a) the nitrogen-doped single crystal silicon wafer has a diameter of from about 150 mm to about 450 mm;
(b) the nitrogen-doped single crystal silicon wafer comprises nitrogen in a concentration from about 1*10 13 nitrogen atoms per cm 3 to about 1*10 15 nitrogen atoms per cm 3 ;
(c) the nitrogen-doped single crystal silicon wafer is characterized by having an increase in bulk micro defect density in a region extending from the center of said wafer to the edge of said wafer by no more than about 200%; and
(d) the nitrogen-doped single crystal silicon wafer is characterized by an increase in radial bulk micro defect size in the region extending from the center of said wafer to the edge of said wafer of less than about 20%.
2. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the wafer is vacancy dominated.
3. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the wafer has an increase in radial bulk micro defect density in a region extending from about 10 mm to the edge of said wafer and to the edge of said wafer of less than about 100%.
4. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the wafer has an increase in radial bulk micro defect size in a region extending from about 10 mm to the edge of said wafer and to the edge of said wafer of less than about 15%.
5. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the wafer further comprises an edge band in a region extending from about 1000 μm to the edge of said wafer and to the edge of said wafer, the edge band comprising oxygen precipitates having an average diameter of from about 30 nm to about 100 nm and an oxygen precipitation density of from about 1*10 8 atoms per cm 3 to about 1*10 10 atoms per cm 3 .
6. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the wafer further comprises an edge band in a region extending from about 1000 μm to the edge of said wafer and to the edge of said wafer, the edge band comprising oxygen precipitates having an average diameter of from about 80 nm to about 100 nm and an oxygen precipitation density of from about 1*10 8 atoms per cm 3 to about 1*10 10 atoms per cm 3 .
7. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the wafer further comprises an edge band in a region extending from about 1000 μm to the edge of said wafer and to the edge of said wafer, the edge band comprising oxygen precipitates having an average diameter of from about 80 nm to about 90 nm and an oxygen precipitation density of from about 1*10 8 atoms per cm 3 to about 1*10 10 atoms per cm 3 .
8. The nitrogen-doped single crystal silicon wafer of claim 1 further comprising an edge band in a region extending from about 1000 μm to the edge of said wafer and to the edge of said wafer, the edge band comprising voids having an average radius of from about 1 nm to about 50 nm.
9. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the diameter is about 300 mm.
10. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the nitrogen concentration is from about 3*10 13 nitrogen atoms per cm 3 to about 2*10 14 nitrogen atoms per cm 3 .
11. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the nitrogen concentration is from about 1*10 14 nitrogen atoms per cm 3 to about 1*10 15 nitrogen atoms per cm 3 .
12. The nitrogen-doped single crystal silicon wafer of claim 1 further comprising:
a layer comprising silicon oxide or silicon nitride in interfacial contact with the front surface of the nitrogen-doped single crystal silicon wafer; and
a device layer in interfacial contact with the layer comprising silicon oxide or silicon nitride.
13. The nitrogen-doped single crystal silicon wafer of claim 1 further comprising an epitaxial layer in interfacial contact with the front surface of the nitrogen-doped single crystal silicon wafer.
14. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the wafer further comprises an edge band in a region extending from about 4000 μm from the edge of said wafer and the edge of said wafer, wherein the bulk micro defect density of the edge band region differs from the remainder of said wafer by no more than about 200%.
15. The nitrogen-doped single crystal silicon wafer of claim 1 wherein the diameter is from about 300 mm to about 450 mm.