Semiconductor device having super junction metal oxide semiconductor structure and fabrication method for the same

A fabrication method for a semiconductor device, the fabrication method comprising:

• forming a first base layer of a first conductivity type;
• forming a drain layer of the first conductivity type on a back side surface of the first base layer;
• forming a second base layer of a second conductivity type in a surface side in the first base layer;
• forming a source layer of the first conductivity type in a surface side in the second base layer;
• forming a gate insulating film on a surface of both the source layer and the second base layer;
• forming a gate electrode on the gate insulating film;
• forming a column layer of the second conductivity type in the first base layer directly below both the second base layer and the source layer by opposing the drain layer so that a long-side direction of the column layer is a direction vertical to a principal surface of the drain layer;
• forming a drain electrode on the drain layer,
• forming a source electrode on both the source layer and the second base layer;
• and
• performing a charged particle irradiation of one of 3He++ and 4He++ to the column layer, wherein
• the column layer and the first base layer are alternately-arranged repeatedly in a direction parallel to the principal surface of the drain layer,
• a bottom surface of the column layer and a top surface of the drain layer are separated from each other, and
• the charged particle irradiation is so performed that an impurity concentration of the first conductivity type has a lowest value, among all values thereof in the drain layer, the column layer and the first base layer, substantially at the bottom surface of the column layer.