| 摘要 |
A latch up in a charge pump device is prevented as well as a withstand voltage of an MOS transistor used in the charge pump device is increased with this invention. A first and a second N-type epitaxial silicon layers are stacked on a P-type single crystalline silicon substrate, and P-type well regions are formed in the second epitaxial silicon layer separated from each other. A P-type isolation layer is formed between the P-type well regions. A P+-type buried layer is formed abutting on a bottom of each of the well regions, an N+-type buried layer is formed abutting on a bottom of the P+-type buried layer, and a transistor for charge transfer is formed in each of the P-type well regions. |
