| 摘要 |
PURPOSE:To increase the capacity of a capacitor without enlarging the size of a chip by providing a concave and convex surface on a part of the chip surface where a capacitor is to be formed, and providing electrodes on said surface through an insulating film. CONSTITUTION:With an oxide film 8 which is formed on the surface of a P type substrate 6 as a mask, N type impurities are selectively diffused and an N<+> region 7 is formed. Thereafter, the surface of the region 7 becomes a state wherein a silicon region is transformed into an oxide film as such, and the concave parts are provided. When films 8 and 8A are removed, the concave and convex surface is formed on the substrate 6. when an N type epitaxial layer 10 is grown on the substrate 10, a new concave and convex surface 11 is formed. At the same time when the emitter diffusion is performed, an N<+> type region 12 is formed on the concave and convex surface 11 by selective diffusion. Since the region 12 is formed in a bent shape, the area is substantially increased in comparison with the case of a flat surface. Then the electrodes 14a and 14B are formed and the capacitor is formed. |
