| 摘要 |
PURPOSE:To prevent electrostatic breakdown by isoplanar structure by forming high-concentration n<+> type layer for extracting potential from an n<+> type buried layer to one part of an island region on the n<+> type buried layer so that the buried layer is used as a resistance section and employing a p-n junction as a protective diode. CONSTITUTION:An n<+> buried layer 12 is formed to a p<->type Si substrate 11. n<+> layers 14, 15 are formed, and an isoplanar oxide film 13 is formed to one part of the Si layer. A p type isolation section 18 is diffused so that a p type impurity is connected to the p type substrate 11. The high-concentration n<+> type layers 14, 15 are separated by the isoplanar oxide film so that the n<+> type buried layer 12 is used as a resistance section and formed at two positions. An Al electrode 16 is brought into ohmic-contact on one n<+> type layer 14, and connected to an external terminal (PAD) for a chip. An Al electrode 17 is brought into ohmic-contact on the other n<+> type layer 15, and connected to a base or an emitter in a transistor to be protected. |
