Semiconductor device

A semiconductor device comprising:

• a semiconductor substrate having a first main surface and a second main surface opposite to the first main surface, an IGBT region, a diode region, and a current sense region being provided along an in-plane direction in the semiconductor substrate,
• the semiconductor substrate including:
• a base layer provided on a first main surface side being a side of the first main surface, in the IGBT region;
• a collector layer provided on a second main surface side being a side of the second main surface, in the IGBT region;
• an anode layer provided on the first main surface side in the diode region;
• a cathode layer provided on the second main surface side in the diode region and adjacent to the collector layer in the in-plane direction;
• a first semiconductor layer provided on the first main surface side in the current sense region and corresponding to the base layer or the anode layer;
• and
• a second semiconductor layer provided on the second main surface side in the current sense region and corresponding to one of the collector layer and the cathode layer,
• wherein
• [Expression 1]
• W>√{square root over (2S+√{square root over (Dτ)}+Dτ)}
• Expression 1 holds where a first distance along the in-plane direction from a channel of the first semiconductor layer to a third semiconductor layer that is an other of the collector layer and the cathode layer is designated as W, a second distance from the channel of the first semiconductor layer to the second semiconductor layer is designated as S, and a diffusion coefficient and a lifetime of a part of the semiconductor substrate between the channel of the first semiconductor layer and the third semiconductor layer are designated as D and τ, respectively.