SEMICONDUCTOR DEVICE HAVING IGBT CELLS AND DIODE CELLS, AND ITS DESIGNING METHOD

摘要

Provided is a semiconductor device comprising a semiconductor substrate (4), IGBT cells (10i, 50i), and diode cells (10d, 30d, 50d). The substrate includes a first layer (4a), a second layer (5), a third layer (6) and a fourth layer (7). The first layer is arranged on a first face of the substrate, and the second layer and the third layer are arranged adjacent to each other on a second face of the substrate. The fourth layer is sandwiched between the first layer, and the second and third layer. The first layer provides the drift layers of the IGBT cells and the diode cells. The second layer provides the collector layers of the IGBT cells. The third layer provides the electrode connecting layer of one of the diode cells. The first layer has a resistivity defined by ?₁[Ocm] and a thickness defined by L₁[µm]. The fourth layer has a resistivity defined by ?₂[Ocm] and a thickness defined by L₂[µm]. The one half of the minimum width of the second layer in the substrate face is defined by W₂[µm]. These values satisfy a relation of (?₁/?₂) x (L₁L₂/W₂