Patent ID: 8299495

Claim:
A reverse conducting IGBT comprising: (a) a rectangular semiconductor substrate having a first and a second main surfaces; (b) a drift region of a first conductivity type occupying essential parts of the semiconductor substrate; (c) an IGBT cell region provided in a surface region of the first main surface of the semiconductor substrate and having a large number of linear gate electrodes extending in an X direction; (d) a collector region of a second conductivity type provided across substantially the entire surface in a surface region of the second main surface of the semiconductor substrate; (e) a large number of dot-shaped diode cathode regions of a first conductivity type provided in a surface region of the second main surface of the semiconductor substrate so as to penetrate through the collector region; and (f) a back side metal electrode layer provided over the second main surface so as to short-circuit the collector region and the large number of dot-shaped diode cathode regions, wherein the large number of dot-shaped diode cathode regions constitute an XY two-dimensional lattice in the second main surface; the lattice constant in the X direction differs from that in a Y direction; and the lattice constant in the Y direction is longer than that in the X direction.