Tunnel field-effect transistor having a stacked structure including a first active region and a second active region

A tunnel field-effect transistor comprising:

• a first active region;
• a second active region provided under the first active region;
• a control electrode provided on the first active region;
• a first active region extension portion extending from the first active region;
• and
• a second active region extension portion extending from the second active region,
• wherein the first active region includes a first-A active region and a first-B active region located at least between the first-A active region and the first active region extension portion,
• an orthographic projection image of the control electrode and an orthographic projection image of the first active region at least partly overlap with each other,
• the second active region exists below the first-A active region,
• the second active region does not exist below the first-B active region, L1-Y<L2-Total is satisfied in a case where:
• a total extension length of an end portion of a portion of the second active region where an orthographic projection image of the second active region overlaps with the orthographic projection image of the first active region is defined as L2-Total;
• and
• a length in a Y direction of the first active region overlapping with the orthographic projection image of the second active region is defined as L1-Y when a direction extending from the first active region to the first active region extension portion is defined as an X direction and a stacked direction of the second active region, the first active region, and the control electrode is defined as a Z direction,
• the second active region includes a plurality of protruding second active region segments, and
• a recess between a first protruding second active region segment and a second protruding second active region segment is embedded with an insulation material,
• a portion of the first active region facing the recess has a characteristic as a first conductivity type,
• the second active region has a characteristic as a second conductivity type different from the first conductivity type, and
• a portion of the first active region facing a protruding second active region segment of the plurality of second active region segments includes a first region having the characteristic as the first conductivity type, and a second region surrounded by the first region and having an impurity concentration lower than an impurity concentration of the first region.

A tunnel field-effect transistor comprising:

• a first active region;
• a second active region provided under the first active region;
• a control electrode provided on the first active region;
• a first active region extension portion extending from the first active region;
• and
• a second active region extension portion extending from the second active region,
• wherein when a portion of the first active region where an orthographic projection image of the control electrode, an orthographic projection image of the first active region, and an orthographic projection image of the second active region overlap with one another is defined as a first-a active region, and a portion of the first active region where the orthographic projection image of the control electrode and the orthographic projection image of the first active region overlap with each other and do not overlap with the orthographic projection image of the second active region is defined as a first-b active region,
• the first-b active region has a characteristic as a first conductivity type and the second active region has a characteristic as a second conductivity type different from the first conductivity type,
• an insulation region is formed under the first-b active region and under the first active region extension portion, and
• the first-a active region includes a first-a1 active region and a first-a2 active region interposed between the first-a1 active region and the first-b active region, having the characteristic as the first conductivity type, and having an impurity concentration higher than an impurity concentration of the first-a1 active region.