| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device having the capacity in the small occupancy area. SOLUTION: N-type capacity regions 30 are formed beneath well layers 2a, 2b on a substrate 1. The parts not formed of the well layers 2a, 2b and the capacity regions 30 correspond to the P type substrate region 1a. The capacity regions 30 are composed of layer regions 30a-30c and a columnar region 30d. The columnar region 30d mutually connects the layer regions 30a-30c by penetrating them while the potential of the whole capacity reigns is decided by the potential given thereto. In such a constitution, the surface only of the columnar region 30d out of the whole capacity regions 30 is exposed in the surface of the substrate thereby making the accuracy area of the semiconductor device narrow. Besides, the area of the interface between a plurality of the columnar regions 30 and the substrate region 1a is wide thereby enabling a large junction capacity to be given. Accordingly, a step down circuit can be operated in a stable state by connecting the large junction capacity to the output side of the step down circuit. |
