Super-junction semiconductor device

A superjunction-semiconductor device comprising:

• a semiconductor substrate layer of a first conductivity type;
• a drift layer comprising a first alternating-conductivity-type layer comprising a first semiconductor region of the first conductivity type and a second semiconductor region of a second conductivity type, the first and second semiconductor regions both being longer than they are wide in a direction perpendicular to a first major surface of the semiconductor layer of the first conductivity type, the first and second semiconductor regions being arranged alternately so that they adjoin each other in parallel to a first major surface of the semiconductor layer of the first conductivity type, so that they adjoin other in parallel to the first major surface of the semiconductor layer of the first conductivity type;
• a main device region and a sensing device region of which the drift layer is the first parallel pn layer, located on a first major surface side;
• the main device region comprising a main gate electrode and a main source electrode;
• the sensing device region comprising a sensing device cell comprising a sensing gate electrode and a sensing source electrode;
• and
• a separation region disposed between the drift layer of the main device region and the drift layer of the sensing region to separate the main device region and the sensing device region, the separation region comprising a third semiconductor region of the first conductivity type and a fourth semiconductor of the second conductivity type, the fourth semiconductor regions being arranged in the third semiconductor region in parallel and perpendicular to the first alternating conductivity-type layer, the fourth semiconductor region being separated from the second semiconductor region of the main device region and the second semiconductor region of the sensing device region and being in an electrically floating state
• wherein the separation region is disposed entirely between the main device region and the sensing device region, the breakdown withstanding section is provided in the peripheral region of the main device region, and the entire fourth semiconductor region is in a floating state.