Semiconductor device with vertical field floating rings and methods of fabrication thereof

A semiconductor device includes a semiconductor substrate having a first conductivity type. A gate structure is supported by a surface of the semiconductor substrate, and a current carrying region (e.g., a drain region of an LDMOS transistor) is disposed in the semiconductor substrate at the surface. The device further includes a drift region of a second, opposite conductivity type disposed in the semiconductor substrate at the surface. The drift region extends laterally from the current carrying region to the gate structure. The device further includes a buried region of the second conductivity type disposed in the semiconductor substrate below the current carrying region. The buried region is vertically aligned with the current carrying region, and a portion of the semiconductor substrate with the first conductivity type is present between the buried region and the current carrying region.