Multi-angle rotation for ion implantation of trenches in superjunction devices
View Patent ↗A method of manufacturing a semiconductor device includes providing a semiconductor wafer and forming at least one first trench in the wafer having first and second sidewalls and a first orientation on the wafer. The first sidewall of the at least one first trench is implanted with a dopant of a first conductivity at a first implantation direction. The first sidewall of the at least one first trench is implanted with the dopant of the first conductivity at a second implantation direction. The second implantation direction is orthogonal to the first implantation direction. The first and second implantation directions are non-orthogonal to the first sidewall.
1. A method of manufacturing a semiconductor device comprising:
(a) providing a semiconductor wafer;
(b) forming at least one first trench in the wafer, the at least one first trench having first and second sidewalls and a first orientation on the wafer;
(c) implanting, with a dopant of a first conductivity, the first sidewall of the at least one first trench at a first implantation direction; and
(d) implanting, with the dopant of the first conductivity, the first sidewall of the at least one first trench at a second implantation direction, the second implantation direction being orthogonal to the first implantation direction, the first and second implantation directions being non-orthogonal to the first sidewall.
2. The method of claim 1 , further comprising:
(e) implanting, with the dopant of the first conductivity, the second sidewall of the at least one first trench at a third implantation direction, the third implantation direction being orthogonal to one of the first implantation direction and the second implantation direction; and
(f) implanting, with the dopant of the first conductivity, the second sidewall of the at least one first trench at a fourth implantation direction, the fourth implantation direction being orthogonal to the third implantation direction, the third and fourth implantation directions being non-orthogonal to the second sidewall.
3. The method of claim 2 , further comprising:
(g) prior to the implantation steps, forming at least one second trench having first and second sidewalls and a second orientation on the wafer, the second orientation being different from the first orientation.
4. The method of claim 3 , wherein the first and second sidewalls of the at least one second trench are implanted with the dopant of the first conductivity during the steps (c)-(f).
5. The method of claim 4 , wherein a concentration of the dopant of the first conductivity in the first and second sidewalls of the at least one first trench is different than a concentration of the dopant of the first conductivity in the first and second sidewalls of the at least one second trench.
6. The method of claim 3 , wherein the second orientation is non-orthogonal to the first orientation.
7. The method of claim 2 , wherein the steps (a)-(f) are performed sequentially.
8. The method of claim 2 , wherein prior to commencement of each of the steps (a)-(f), the respective preceding step is substantially completed.
9. The method of claim 2 , wherein prior to commencement of each of the steps (a)-(f), the respective preceding step is fully completed.
10. A semiconductor device formed by the method of claim 2 .
11. The method of claim 1 , wherein the steps (a)-(d) are performed sequentially.
12. The method of claim 1 , wherein prior to commencement of each of the steps (a)-(d), the respective preceding step is substantially completed.
13. The method of claim 1 , wherein prior to commencement of each of the steps (a)-(d), the respective preceding step is fully completed.