| 摘要 |
To control the uneven distribution of current density and reduce the area of an ESD protection circuit in an SCR-type ESD protection device. An N-type well 11, and P-type wells 12 a and 12 b disposed oppositely and adjacent to the N-type well 11, with the N-type well 11 interposed between them, are formed on the surface of a semiconductor substrate. A high concentration N-type region 15 a is formed on the surface of the P-type well 12 a, a high concentration N-type region 15 b is formed on the surface of the P-type well 12 b, and each of them is grounded. Further, a high concentration P-type region 14 a is formed, oppositely to the high concentration N-type region 15 a, on the surface of the N-type well 11, and a high concentration P-type region 14 b is formed, oppositely to the high concentration N-type region 15 b, on the surface of the N-type well 11, and each of them is connected to an I/O pad. A high concentration N-type region 13 is formed on the N-type well 11, being interposed between the high concentration P-type region 14 a and the high concentration P-type region 14 b, and connected to a trigger device. A surge loaded on the I/O pad is released to the ground terminal via the SCR structures on the both sides.
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