| 摘要 |
PURPOSE:To provide a universal integrated circuit simply in high integrity by forming an island region of the same conducting type as a high impurity density buried layer directly over a high impurity density buried region in a semiconductor substrate, making the island region contact with the buried layer and thus forming a transistor, resistors and the like on the island region. CONSTITUTION:An n<+>type buried layer 2 is selectively formed on the surface of a p-type semiconductor substrate 1. A p-type epitaxial layer 3 is then formed thereon, and an n-type region 4 is formed by an ion implantation process. Unit functions of npn transistor, diode, resistors and the like are then formed in the n-type ion implanted region 4. A resistor 9 and a MOS transistor 10 as also formed on the region where n-type ion is not implanted of the layer 3. An isolation is conducted by thick oxide films 5. Thus, the epitaxial layer of the same conducting type as the substrate is formed to form an island region therein by a simple electric isolation to reduce the margin in designing it so as to enhance the integrity of the semiconductor integrated circuit. |
