| 摘要 |
PURPOSE:To reduce the area of a capacitor as well as to lower the parasitic capacity of the titled device by a method wherein, in the semiconductor integrated circuit device having a capacitor, the electrode of a semiconductor substrate is composed of the first region whereon impurities are ion-implanted and the second region of high density. CONSTITUTION:An N type buried layer 2 is formed on a P type silicon substrate 1, an N type epitaxial layer 3 is formed, and a region 4A to be turned to the substrate side electrode of a capacitor is formed together with a P type isolation region 4. After a field oxide film 6 has been formed by performing a selective oxidation using nitride films 5 and 5-1 as a mask, a P type region 9 is formed by ion-implanting boron. The oxidation-resistant film 5-1 of a contact region 7 is removed, and electrodes 8A and 8B are provided. The distance between the P type isolation region 4 and the substrate side electrode can be determined by the P type ion implanted layer 9, and the distance between said region 4 and the substrate side electrode can be reduced. Also, the N type buried layer 2 can be reduced in size without changing the area of the oxidation-resistant film 5, thereby enabling to reduce the parasitic capacity. |
