Semiconductor switching element

A switching element comprising:

• a semiconductor substrate on an upper surface of which a trench is provided;
• a gate insulation layer covering an inner surface of the trench;
• and
• a gate electrode arranged in the trench and insulated from the semiconductor substrate by the gate insulation layer,
• wherein the semiconductor substrate comprises:
• a first conductivity type first semiconductor region being in contact with the gate insulation layer;
• a second conductivity type body region being in contact with the gate insulation layer on a lower side of the first semiconductor region;
• a second conductivity type bottom region being in contact with the gate insulation layer at a bottom surface of the trench;
• and
• a first conductivity type second semiconductor region extending from a position being in contact with a lower surface of the body region to a position being in contact with a lower surface of the bottom region, being in contact with the gate insulation layer on a lower side of the body region and separated from the first semiconductor region by the body region, and
• the bottom region comprises:
• a low concentration region being in contact with the gate insulation layer in a first range of the bottom surface that is positioned at an end in a long direction of the trench;
• and
• a high concentration region being in contact with the gate insulation layer in a second range of the bottom surface that is adjacent to the first range, and a second conductivity type impurity concentration of which being higher than that of the low concentration region.