Semiconductor device and manufacturing method thereof

摘要

A semiconductor device for a charge pump device suitable for providing large current capacity and preventing a latch up from occurring is offered. 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. P+-type buried layers abutting on bottoms of the P-type well regions and N+-type buried layers abutting on bottoms of the P+-type buried layers and electrically isolating the P-type well regions from the single crystalline silicon substrate are formed. An MOS transistor is formed in each of the P-type well regions and a drain layer of the MOS transistor and each of the P-type well regions are electrically connected.