| 摘要 |
PURPOSE:To obtain an IC, in which dispersion in breakdown voltage of a Zener diode and decrease in drift due to current condition are not yielded, by providing a P<+>N<+> junction comprising an N<+> type embedded layer and a P<+> type isolating diffused layer in the Zener diode, which is simultaneously formed as a transistor. CONSTITUTION:A P<+> type isolating embedded layer 12 and an N<+> type embedded layers 13 and 13a are diffused and formed in a P type semiconductor substrate 11. An N type layer 14 is epitaxially grown on the entire surface including the layers. Then a P<+> type isolating diffused layer 15 is formed on the layer 12, and an isolating region is provided in the layer 14. At this time, a P<+> type isolating diffused layer 15a is provided also in the embedded layer 13 in a region where a Zener diode is to be formed. An anode is formed so as to reach the layer 13a. Thereafter, N<+> type collector wall diffused layers 18 and 18a for decreasing ON resistance are formed in the embedded layer 13 in an N-P-N transistor forming region and the embedded layer 13a in the Zener diode forming region. Then a P<+> type diffused layer 16a for connecting electrodes and N<+> type collector diffused layers 17c and 17d are provided on a P<+> type base diffused layer 16b and and anode 15a. |
