VARIABLE VOLTAGE CAPACITIVE ELEMENT AND ITS PRODUCING PROCESS, SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE, AND ITS PRODUCING PROCESS

摘要

PROBLEM TO BE SOLVED: To provide a variable voltage capacitive element having a high variable capacity ratio and a low series parasitic resistance and can be fabricated simultaneously with other high speed semiconductor devices on a substrate. SOLUTION: The variable voltage capacitive element has a first heavily doped diffusion area formed in a first conductivity type region in a substrate to extend continuously at least from a region immediately below a control electrode on the substrate along the surface of the substrate to a region on the outside of a side wall insulating film when viewed from the control electrode, and a second heavily doped diffusion area of a first conductivity type formed contiguously to the first heavily doped diffusion area in the first conductivity type region at a deeper position. The first heavily doped diffusion area has a substantially identical carrier density in the region immediately below the control electrode and in the region on the outside of the side wall insulating film on the surface of the substrate. COPYRIGHT: (C)2004,JPO