Patent ID: 7846821

Claim:
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 sidewalls and a first orientation on the wafer; (c) forming at least one second trench in the wafer, the at least one second trench having sidewalls and a second orientation on the wafer, the second orientation being different from the first orientation; (d) directing an ion implantation beam from a first implantation direction at the at least one first trench and the at least one second trench; (e) directing an ion implantation beam from a second implantation direction at the at least one first trench and the at least one second trench, the second implantation direction being different than the first implantation direction by 90°; (f) directing an ion implantation beam from a third implantation direction at the at least one first trench and the at least one second trench, the third implantation direction being different than the first implantation direction by 180°; and (g) directing an ion implantation beam from a fourth implantation direction at the at least one first trench and the at least one second trench, the fourth implantation direction being different than the first implantation direction by 270°, the first, second, third, and fourth implantation directions being non-orthogonal to at least one of the first orientation and the second orientation.