| 摘要 |
Both P type and N type impurities are implanted from a plurality of directions. The tilt angle theta of the implantation direction against the normal of the main surface of a semiconductor substrate is fixed to 10°, and the deflection angle phi is set to such four directions (X, X+90°, X+180°, and X+270°, where X is an arbitrary angle) that projecting components of a vector indicating the implantation direction are opposed to each other on two lines that cross each other at right angles along the main surface of the semiconductor substrate. Thereby, the dependency of the breakdown voltage of element isolation on the direction of a well boundary is suppressed to realize a high breakdown voltage of element isolation in all directions.
|
