In an example, a semiconductor device includes a semiconductor substrate of a first conductivity type and a semiconductor region of the first conductivity type over the semiconductor substrate. A well region of a second conductivity type is in the semiconductor region. A doped region of the first conductivity type is in the well region. A doped region of the second conductivity type is in the well region. A doped region of the second conductivity type is in the semiconductor substrate at a bottom side. A doped region of the first conductivity type is in the semiconductor substrate at the bottom side. A first conductor is at a top side of the semiconductor region and a second conductor is at the bottom side. In some examples, one or more of doped regions at the bottom side is a patterned doped region.