| 摘要 |
PURPOSE:To obtain preferable constant-voltage characteristic of a constant-voltage diode without altering the fundamental manufacturing step of a condutor integrated circuit by forming the first diffused layer of a P type impuirty density and the second diffused layer of N type high impurity density on a P type silicon substrate. CONSTITUTION:An N type high density diffused layer 2 is selectively formed on a P type silicon substrate 1, a P type impurity diffused layer 3 of high density is formed on the layer 2, and a P type downward floating upward isolating diffused layer 4 of high density is formed. A silicon oxidized film 9 is produced on the surface of an epitaxial layer 5, holes are selectively opened, and P type impurity diffused layers 7a, 8a and N type diffused layer 6a are sequentially respectively formed in the holes. Subsequently, when the element is heat treated in high nitrogen or oxygen atmosphere, the layers 6a, 7a are diffused in the layer 3 and the layer 8a is diffused in the layer 4 to be superposed each other, thereby forming the second and third diffused layers 6, 7 and an isolation diffused layer 8. At this time, the layer 5 is electrically isolated via the layers 4, 8, thereby forming an insular region. A contacting hole is eventually opened at the film 9, metal wirings are performed, and electrodes 10a, 10b are formed. |
