Patent ID: 7235857

Claim:
A semiconductor device, comprising: a silicon carbide substrate having front and back surfaces facing each other and including a first silicon carbide substrate region and a second silicon carbide substrate region separate from said first silicon carbide substrate region; a unitary solid isolating region having a substantially uniform composition and a substantially uniform width disposed within said silicon carbide substrate and directly connecting the first silicon carbide substrate region to the second silicon carbide substrate regions so that the first and second silicon carbide substrate regions are not in contact with each other; and first and second MOSFETs formed on opposite sides of the solid isolating region, respectively, wherein the first MOSFET is a first vertical MOSFET comprising a first vertical MOSFET silicon carbide substrate region of a first conductivity type; a first vertical MOSFET body region of a second conductivity type formed on the front side of the silicon carbide substrate; a first vertical MOSFET gate electrode; and a first vertical MOSFET doped region of the first conductivity type formed in the first vertical MOSFET body region, and the second MOSFET is a second vertical MOSFET comprising a second vertical MOSFET silicon carbide substrate region of the first conductivity type; a second vertical MOSFET body region of the second conductivity type formed on the back side of the silicon carbide substrate; a first vertical MOSFET gate electrode; and a second vertical MOSFET doped region of the first conductivity type formed in the second vertical MOSFET body region, wherein in each of the first and second vertical MOSFET, a current flowing between the respective silicon carbide substrate region and doped region is controlled by the respective MOSFET gate electrode.