Semiconductor device having IGBT and FWD on same substrate

A semiconductor device comprising:

• a semiconductor substrate having a first conductive type and including a first side and a second side;
• an IGBT element for flowing current in a thickness direction of the substrate, wherein the IGBT element is arranged in the substrate, the IGBT includes a collector region having a second conductive type, and the collector region is arranged in a surface portion of the second side of the substrate;
• a FWD element including a cathode region having the first conductive type, wherein the cathode region is arranged in another surface portion of the second side of the substrate in such a manner that the cathode region is adjacent to the collector region along with a parallel direction of the substrate;
• a base layer having the second conductive type and arranged on the first side of the substrate;
• a plurality of trench gate structures, each of which includes a trench on the first side of the substrate and a conductive film in the trench via an insulation film,
• wherein the base layer is divided by the trench gate structures into a plurality of first and second regions,
• wherein the trench gate structures include a gate electrode in the IGBT element;
• wherein each first region includes an emitter region in the IGBT element,
• wherein each emitter region is arranged in a surface portion of the first region, contacts the gate electrode, has the first conductive type, and has an impurity concentration higher than the substrate,
• wherein each second region does not include the emitter region,
• wherein each first region together with the emitter region is electrically coupled with an emitter electrode in the IGBT element,
• wherein the first regions include a collector side first region and a cathode side first region,
• wherein the collector side first region is disposed over the collector region, and the cathode side first region is disposed over the cathode region,
• wherein the second regions include a collector side second region and a cathode side second region,
• wherein the collector side second region is disposed over the collector region, and the cathode side second region is disposed over the cathode region,
• wherein the cathode side second region is divided into a first cathode part and a second cathode part,
• wherein the collector side second region is divided into a first collector part and a second collector part,
• wherein the first cathode part of the cathode side second region is electrically coupled with the emitter electrode,
• wherein the second cathode part of the cathode side second region has a floating potential,
• wherein a number of second regions in the first cathode part of the cathode side second region is larger than a number second regions in the second cathode part of the cathode side second region,
• wherein the first collector part of the collector side second region has a floating potential,
• wherein the second collector part of the collector side second region is electrically coupled with the emitter electrode, and
• wherein a number of second regions in the first collector part of the collector side second region is larger than a number of second regions in the second collector part of the collector side second region.