| 摘要 |
PURPOSE:To increase the storage capacitance of the capacity of a trench without increasing the depth of the trench by a method wherein a plurality of capacitors, each consisting of a dielectric layer and conductor layers pinching this dielectric layer between them, are ar ranged in parallel and coaxially in the trench from the side surface of the trench toward the center of the trench to increase a laminated capacity. CONSTITUTION:The end parts of the respective both electrodes of 3 pieces of capacitors of a first capacitor C1 (CAB), which is formed in a P-type semiconductor substrate along the inner face of a trench T and consists of a first electrode A consisting of an N-type diffused region and a second electrode B arranged coaxially through a dielectric layer on the inner side of the electrode A, a second capacitor C2 (CBC) consisting of the electrode B and a third electrode C in the same way as the above and a third capacitor C3 (CCD) consisting of the electrode C and a fourth electrode D in the same way as the above are respectively connected to each other by an N-type diffused region An under the lower part of the trench and a grounding wiring LG on the substrate and a parallel circuit consisting of 3 pieces of the capacitors is constituted. Whereupon, the storage capacitance CS1 of the capacity of the trench is represented by CS1=C1+C2+C3 and the area ratio, which is occupied by the capacity, becomes larger than the area ratio, which is occupied by the capacity of the existing trench of a singlet structure consisting of the capacitor C1 only. |
