Field-Effect Semiconductor Device and a Manufacturing Method Therefor

A field-effect semiconductor device, comprising:

• a semiconductor body comprising:
• a first side;
• a second side opposite the first side;
• a semiconductor structure of a second conductivity type at least substantially extending from the first side to the second side;
• and
• a drift region of a first conductivity type arranged, in a vertical cross-section substantially perpendicular to the first side, between two portions of the semiconductor structure;
• a first metallization arranged on the second side and in Ohmic connection with the semiconductor structure;
• a second metallization arranged on the first side and in Ohmic connection with the drift region;
• a plurality of gate electrodes arranged adjacent to the second side, overlapping with the drift region in a normal projection onto a horizontal plane substantially parallel to the first side, and electrically insulated from the semiconductor body;
• a first through contact structure extending at least between the first side and the second side, and comprising a conductive region in Ohmic connection with the gate electrodes, and a dielectric layer electrically insulating the conductive region from the semiconductor body so that at least a portion of the semiconductor structure is, in the normal projection onto the horizontal plane, arranged between the first through contact structure and the gate electrodes;
• and
• a gate pad arranged on the first side and in Ohmic connection with the conductive region.

A method for forming a field-effect semiconductor device, the method comprising:

• providing a wafer comprising:
• a semiconductor body having a first side and a second side opposite the first side, and comprising a drift region of a first conductivity type and a semiconductor structure of a second conductivity type extending from the first side to the second side, and surrounding the drift region in a normal projection onto a horizontal plane substantially parallel to the first side;
• and
• a first dielectric layer arranged at the first side;
• forming a first deep trench from the second side at least to the dielectric layer;
• forming a dielectric sidewall layer at a sidewall of the first deep trench;
• forming a conductive region at the sidewall layer in the first deep trench;
• forming a plurality of gate electrodes adjacent to the second side and overlapping with the drift region in the normal projection onto the horizontal plane;
• forming a first metallization on the second side and in Ohmic connection with the semiconductor structure;
• and
• forming, opposite to the first metallization, a second metallization in Ohmic connection with the drift region and a gate metallization in Ohmic connection with the conductive region.