| 摘要 |
A device includes a diode, which includes a first, a second, and a third doped region in a semiconductor substrate. The first doped region is of a first conductivity type, and has a first impurity concentration. The second doped region is of the first conductivity type, and has a second impurity concentration lower than the first impurity concentration. The second doped region encircles the first doped region. The third doped region is of a second conductivity type opposite the first conductivity type, wherein the third doped region overlaps a portion of the first doped region and a portion of the second doped region. |
