SEMICONDUCTOR CAPACITOR DEVICE

摘要

PURPOSE:To produce a capacitor element with sufficient withstand voltage and high capacity per unit area by a method wherein the second conductive type layer with low concentration is epitaxially grown on the first conductive type semiconductor substrate through the intermediary of the second conductive type buried layer with high concentration to provide the first conductive type well region reaching the buried layer from the surface while a P-N junction produced by the well region and the buried layer is utilized as a capacity. CONSTITUTION:An N type layer 3 is epitaxially grown on a P type Si substrate 1 as main body of IC through the intermediary of an N<+> type buried layer 2 to implant a P type impurity ion from surface performing extended diffusion and forming a P type separated region 4 reaching the substrate 1. Next an NPN transistor and a diffusion resistor are provided in the layer 3 encircled by the region 4 to utilize the layer 3 as a capacity. In other words, a P type well region 8 reaching the layer 2 is diffusion-formed in the layer 3 to utilize a P-N junction produced between the region 8 and the layer 2 as a capacity C1. Later the overall surface is covered with an insulating film 7 and windows are opened to fix electrodes 9 and 9' respectively on the layer 3 and the region 8.