Annealed wafer and manufacturing method of annealed wafer
View Patent ↗An annealed wafer in which oxygen precipitation is uniform in the substrate plane and a manufacturing method thereof are provided. A nitrogen-doped silicon single crystal substrate pulled at the cooling rate of 4° C./minute or more during crystal growth between 1100 and 1000° C. wherein the nitrogen concentration is 1×10 14 to 5×10 15 atoms/cm 3 and V/G satisfies predetermined conditions serves as a substrate, and the substrate is subjected to heat treatment in a non-oxidative atmosphere.
1. A method for manufacturing an annealed wafer, the method comprising the steps of:
providing a silicon single crystal substrate having a volume density of voids with a size of 50 nm or less being less than 1×10 4 /cm 3 , and wherein providing the silicon single crystal substrate includes growing a silicon single crystal ingot by the Czochralski method using a nitrogen dopant concentration, a relative V/G value, and a cooling rate defined over a temperature range, from 1100° C. to 1000° C., wherein the nitrogen dopant concentration is from 1×10 14 atoms/cm 3 to 5×10 14 atoms/cm 3 , the relative V/G value is from 1.3 to 1.5, and the cooling rate is 4° C./min or more; and
annealing the substrate.
2. The method of claim 1 further wherein the substrate has a density of dislocation pits, and wherein the density of the dislocation pits having a size of at least about 1 μm is no more than about 1.0/cm 2 .
3. The method of claim 1 , wherein
the step of growing the silicon single crystal ingot by the Czochralski method includes using a V/G upper limit calculated as a function of the nitrogen dopant concentration and a V/G crit determined without the nitrogen dopant.
4. The method of claim 1 , further wherein the step of growing the silicon single crystal ingot uses a V/G lower limit calculated as a function of the nitrogen dopant concentration and the V/G crit.
5. The method Of claim 1 further including a step of applying to the substrate a heat treatment at between about 1150° C. and about 1250° C.
6. The method of claim 5 wherein the heat treatment is applied for between about 10 minutes and about two hours.
7. The method of claim 5 wherein the heat treatment is applied in a rare gas having an impurity of no more than about 5 ppm.
8. The method of claim 5 wherein the heat treatment creates on the surface of the substrate an oxide film thickness of no more than about 2 nm.
9. A method for manufacturing an annealed wafer, the method comprising the steps of:
providing a silicon single crystal substrate having, a volume density of voids with a size of 50 nm or less being less than 1×10 4 /cm 3 , and wherein providing the silicon single crystal substrate includes growing a silicon single crystal ingot by the Czochralski method using a nitrogen dopant concentration, a relative V/G value, and a cooling rate defined over a temperature range from 1100° C. to 1000° C., wherein the nitrogen dopant concentration is from 1×10 14 atoms/cm 3 to 5×10 14 atoms/cm 3 , the relative V/G value is from 1.3 to 1.5, and the cooling rate is 5° C./min or more; and
annealing the substrate.
10. The method of claim 9 further wherein the substrate has a density of dislocation pits, and wherein the density of the dislocation pits having a size of at least about 1 μm is no more than about 10/cm 2 .
11. The method of claim 9 , wherein
the step of growing the silicon single crystal ingot by the Czochralski method includes using a V/G upper limit calculated as a function of the nitrogen dopant concentration and a V/G crit determined without the nitrogen dopant.
12. The method of claim 9 , further wherein the step of growing the silicon single crystal ingot uses a V/G lower limit calculated as a function of the nitrogen dopant concentration and the V/G crit.
13. The method of claim 9 further including a step of applying to the substrate a heat treatment at between about 1150° C. and about 1250° C.
14. The method of claim 5 wherein the heat treatment is applied for between about 10 minutes and about two hours.
15. The method of claim 14 wherein the teat treatment is applied in a rare gas having an impurity of no more than about 5 ppm.
16. The method of claim 14 wherein the heat treatment creates on the surface of the substrate an oxide film thickness of no more than about 2 nm.