Oxygen precipitation in heavily doped silicon wafers sliced from ingots grown by the Czochralski method
View Patent ↗A method for controlling oxygen precipitation in a single crystal silicon wafer having a wafer resistivity of less than about 10 milliohm-cm is provided so that the wafer has uniformly high oxygen precipitation behavior from the central axis to the circumferential edge. The single crystal silicon wafer comprises an additional dopant selected from among carbon, arsenic, and antimony.
1. A p-type single crystal silicon wafer sliced from an ingot grown by the Czochralski method, the p-type single crystal silicon wafer having a wafer resistivity of less than about 10 milliohm-cm, the p-type single crystal silicon wafer sliced from an ingot grown by the Czochralski method and comprising a front surface, a back surface, a central plane between the front and back surfaces, a circumferential edge joining the front and back surface, a central axis perpendicular to the central plane, and a bulk layer which comprises the region of the wafer between the central plane and front surface, wherein the p-type single crystal silicon wafer is vacancy dominant from the central axis to the circumferential edge, the p-type single crystal silicon wafer comprising:
boron dopant at a mean boron concentration of at least about 1×10 19 atoms per cubic centimeter; and
arsenic at a mean arsenic concentration of at least about 3×10 18 atoms per cubic centimeter; and
oxygen precipitates at an average concentration of at least about 5×10 8 precipitates/cm 3 from the central axis to the circumferential edge, wherein the single crystal silicon wafer comprises no annular region in which the oxygen precipitate concentration is less than about 5×10 8 precipitates/cm 3 .
2. A p-type single crystal silicon wafer sliced from an ingot grown by the Czochralski method, the p-type single crystal silicon wafer having a wafer resistivity of less than about 10 milliohm-cm, the p-type single crystal silicon wafer sliced from an ingot grown by the Czochralski method and comprising a front surface, a back surface, a central plane between the front and back surfaces, a circumferential edge joining the front and back surface, a central axis perpendicular to the central plane, and a bulk layer which comprises the region of the wafer between the central plane and front surface, wherein the p-type single crystal silicon wafer is vacancy dominant from the central axis to the circumferential edge, the p-type single crystal silicon wafer comprising:
boron dopant at a mean boron concentration of at least about 1×10 19 atoms per cubic centimeter; and
antimony at a mean antimony concentration of at least about 5×10 17 atoms per cubic centimeter; and
oxygen precipitates at an average concentration of at least about 5×10 8 precipitates/cm 3 from the central axis to the circumferential edge, wherein the single crystal silicon wafer comprises no annular region in which the oxygen precipitate concentration is less than about 5×10 8 precipitates/cm 3 .
3. A p-type single crystal silicon wafer sliced from an ingot grown by the Czochralski method, the p-type single crystal silicon wafer having a wafer resistivity of less than about 10 milliohm-cm, the p-type single crystal silicon wafer sliced from an ingot grown by the Czochralski method and comprising a front surface, a back surface, a central plane between the front and back surfaces, a circumferential edge joining the front and back surface, a central axis perpendicular to the central plane, and a bulk layer which comprises the region of the wafer between the central plane and front surface, the p-type single crystal silicon wafer comprising:
boron dopant at a mean boron concentration of at least about 1×10 19 atoms per cubic centimeter; and
a second dopant selected from the group consisting of arsenic at a mean arsenic concentration of at least about 3×10 18 atoms per cubic centimeter, antimony at a mean antimony concentration of at least about 5×10 17 atoms per cubic centimeter, and a combination thereof, wherein the concentration of the second dopant is less than the concentration of the boron dopant; and
oxygen precipitates at an average concentration of at least about 5×10 8 precipitates/cm 3 from the central axis to the circumferential edge, wherein the single crystal silicon wafer comprises no annular region in which the oxygen precipitate concentration is less than about 5×10 8 precipitates/cm 3 .
4. The p-type single crystal silicon wafer of claim 3 comprising arsenic at a mean arsenic concentration at least about 3×10 18 atoms per cubic centimeter and antimony at a mean antimony concentration of at least about 5×10 17 atoms per cubic centimeter.
5. The p-type single crystal silicon wafer of claim 3 comprising arsenic at a mean arsenic concentration at least about 3×10 18 atoms per cubic centimeter.
6. The p-type single crystal silicon wafer of claim 3 comprising antimony at a mean antimony concentration of at least about 5×10 17 atoms per cubic centimeter.
7. The p-type single crystal silicon wafer of claim 3 having a wafer resistivity of less than about 5 milliohm-cm.
8. The p-type single crystal silicon wafer of claim 3 comprising oxygen precipitates at an average concentration of at least about 1×10 10 precipitates/cm 3 .
9. The p-type single crystal silicon wafer of claim 3 wherein the concentration of the second dopant is less than 1×10 19 atoms per cubic centimeter.
10. The p-type single crystal silicon wafer of claim 3 wherein the concentration of the second dopant is less than 5×10 18 atoms per cubic centimeter.
11. The p-type single crystal silicon wafer of claim 3 comprising an oxygen concentration between about 4.5×10 17 atoms/cm 3 and about 5.5×10 17 atoms/cm 3 .
12. The p-type single crystal silicon wafer of claim 3 comprising an oxygen concentration of less than about 4.5×10 17 atoms/cm 3 .
13. The p-type single crystal silicon wafer of claim 3 comprising an oxygen concentration between about 5.5×10 17 atoms/cm 3 and about 8×10 17 atoms/cm 3 .
14. The p-type single crystal silicon wafer of claim 3 comprising an oxygen concentration between about 6×10 17 atoms/cm 3 and about 9×10 17 atoms/cm 3 .
15. The p-type single crystal silicon wafer of claim 3 comprising an oxygen concentration between about 7.5×10 17 atoms/cm 3 and about 8.5×10 17 atoms/cm 3 .
16. The p-type single crystal silicon wafer of claim 3 comprising oxygen precipitates at an average concentration of at least about 1×10 9 precipitates/cm 3 .
17. The p-type single crystal silicon wafer of claim 16 comprising no annular region in which the oxygen precipitate concentration is less than about 1×10 9 precipitates/cm 3 .
18. The p-type single crystal silicon wafer of claim 3 comprising oxygen precipitates at an average concentration of at least about 5×10 9 precipitates/cm 3 .
19. The p-type single crystal silicon wafer of claim 18 comprising no annular region in which the oxygen precipitate concentration is less than about 5×10 9 precipitates/cm 3 .
20. The p-type single crystal silicon wafer of claim 19 comprising no annular region in which the oxygen precipitate concentration is less than about 1×10 10 precipitates/cm 3 .