Semiconductor devices and methods for manufacturing the same

A semiconductor device includes a semiconductor substrate having a first conductivity type, wherein the semiconductor substrate includes a first region and a second region. The semiconductor device also includes a buried layer disposed in the first region of the semiconductor substrate and having the first conductivity type, wherein the buried layer has a dopant concentration that is greater than that of the semiconductor substrate. The semiconductor device further includes an epitaxial layer disposed on the semiconductor substrate, and a first element disposed on the first region of the semiconductor substrate, wherein the first element includes a bipolar-complementary metal oxide semiconductor (CMOS)-double diffused metal oxide semiconductor (DMOS) (BCD) transistor. In addition, the semiconductor device includes a second element disposed on the second region of the semiconductor substrate, wherein the second element includes an ultra-high voltage (UHV) transistor.