Semiconductor element

A semiconductor element comprising:

• a first semiconductor layer having a first conductivity type and a first side face;
• a second semiconductor layer laminated on the first semiconductor layer, the second semiconductor layer having a second conductivity type, a top surface, and a second side face;
• a third semiconductor layer laminated on a first part of the top surface, the third semiconductor layer having the first conductivity type;
• a first electrode electrically connected to the first semiconductor layer;
• a second electrode located on a second part of the top surface and surrounding the third semiconductor layer;
• and
• a third electrode located on the third semiconductor layer;
• wherein
• an inactive portion is located outside an outside end of the second electrode, on the top surface, as seen in a plan view,
• the inactive portion is formed by implanting ions of one element, selected from the group consisting of helium and argon, into the first and second semiconductor layers, and
• the inactive portion extends from the top surface, on one side of a junction of the first and second semiconductor layers, to a position on an opposite side of the junction of the first and second semiconductor layers.